Anatomic Sciences

The vagus nerve consists of five components:

Branchial motor (special visceral efferent) Visceral motor (general visceral efferent) Visceral sensory (general visceral afferent) General sensory (general somatic afferent) Special sensory (special afferent)

Name the glands found in the submucosa of the duodenum that secrete an alkNa- line mucus to protect the walls of the mucosa. • Peyer's patches • Glands of Kerckring • Hertwig's glands • Brunner's glands • Crypts of Lieberkuhn

Brunner's glands Brunner's glands (also called duodenal glands or submucosal glands) are small, branched, coiled, tubular glands situated deeply in the submucosa of the duodenum. These glands secrete an alkaline mucus to protect the walls of the mucosa from enzymes in the intestinal juice. Note: Histologically, it is possible to distinguish the duodenum from the stomach by the presence of these submucosal glands. Remember: 1. The duodenum is the first part of the small intestine and measures around 12 inches in length. The duodenum has a "C" shape, with the curvature of the "C" encircling the head of the pancreas. It is the shortest but widest part of the small intestine. 2. The interior of the duodenum has a folded surface, which increases the available surface area for absorption of sugars, fats, and amino acids. 3. It is retroperitoneal (lie behind the peritoneum). 4. It receives the common bile duct and pancreatic duct at the duodenal papilla (which is a small, rounded elevation in the wall of the duodenum). 5. The duodenum receives blood from the superior pancreaticoduodenal artery, a branch of the gastroduodenal artery, and the inferior pancreaticoduodenal artery, a branch of the superior mesenteric artery. Important: The sympathetic and parasympathetic divisions of the autonomic nervous system control contraction of smooth muscles in the intestinal wall. (1) Sympathetic: The splanchnic nerve passes through the celiac plexus. Postganglionic fibers innervate the small intestine. Sympathetic stimulation slows motility of the small intestine. (2) Parasympathetic: The vagus nerve supplies a vast distribution of parasympathetic fibers. Postganglionic fibers from the celiac plexus associated with the vagus nerve innervate the small intestine. Parasympathetic stimulation of the small intestine causes increased motility. Note: The preganglionic parasympathetic neurons to the duodenum are located in the dorsal motor nucleus of the vagus nerve.

The inferior alveolar vein, artery, and nerve along with the lingual nerve are found in the space between the

medial pterygoid muscle and the ramus of the mandible (pterygomandibular space).

Which type of muscle cell uniquely contains intercalated discs? • Skeletal muscle cell • Cardiac muscle cell • Smooth muscle cell

Cardiac muscle cell Smooth muscle fibers are composed of uninucleate, spindle-shaped cells (fusiform cells). They are much smaller than skeletal muscle fibers. The nuclei are situated in the widest part of each fiber. They do not possess T tubules, and their sarcoplasmic reticulum is poorly developed. These muscle fibers do not possess regularly ordered myofibrils and are therefore not striated. Their contraction process is slow and not subject to voluntary control. Skeletal muscle fibers are composed of bundles of very long, cylindric, multinucleated cells that possess regularly ordered myofibrils that are responsible for the striated appearance of the cell. The nuclei are either slender ovoid or elongated and are situated peripherally. They do contain transverse tubules (T tubules), and the sarcoplasmic reticulum is very well-developed. Their contraction is quick, forceful, and usually under voluntary control. The myofibrils (actin and myosin) are the contractile element. Remember: Cardiac muscle fibers contain centrally placed nuclei as well as intercalated discs (contain desmosomes and gap junctions), which represent junctions between cardiac muscle cells. I. The satellite cell is responsible for skeletal muscle regeneration. Notes' 2. Two T tubules lie within a single skeletal muscle sarcomere. 3. In skeletal muscle, a triad refers to a T tubule sandwiched between two dilated cisternae of the sarcoplasmic reticulum. 4. Motor units consist of a motor neuron and all the muscle fibers it supplies. 5. The major regulatory proteins in muscle tissue are troponin and tropomyosin.

Which can be defined as a tube-like passage running through a bone?

Meatus

The preferred site for vitamin B12 absorption is the: • Duodenum • Jejunum • Ileum • Cecum

Ileum The small intestine is the main site of absorption of digested food. The small intestine is specialized for the completion of the digestion processes and the subsequent absorption of the digested products. The small intes¬tine consists of three main segments : the duodenum, jejunum, and ileum. Characteristic features of the small intestine include: • Intestinal villi. These are finger-like projections into the lumen (consisting of surface epithelium and underlying lamina propria). *** The epithelium lining the lumen consists of a simple columnar epithelium with goblet cells. The api¬cal surface of the absorptive epithelial cells has a "brush border" (resulting from an orderly arrangement of closely packed microvilli, which may number several hundred per absorptive cell). The main function of the microvilli is to increase the surface area available for absorption. *** The lamina propria of the small intestine is formed from loose connective tissue. This contains blood vessels, nerves, and large lymphatic vessels (site of absorption of lipids). • Intestinal glands. These are simple tubular glands that open to the intestinal lumen between the base of the villi. The intestinal glands are sometimes called the crypts of Lieberkuhn. Secretory cells (Paneth cells) with large acidophilic granules are found at the base of the intestinal glands. The function of these secretory cells is still not fully understood, but it is known that they secrete lysozyme, which has anti-bac¬terial properties. • Valves of Kerckring. The lining of the small intestine has permanent folds known as valves of Kerckring or plicae circulares. These are most prominent in the jejunum. These folds, seen macroscopically in trans¬verse sections, consist of mucosa and submucosa. Important: 1. The main distinguishing feature of the duodenum is the presence of glands in the submucosa. These duo¬denal or Brunner's glands produce alkaline secretions to counteract the effects of gastric acids that reach the duodenum. These glands also provide the necessary alkaline environment for the functioning of the exocrine pancreatic secretions. 2. The main distinguishing feature of the jejunum is the presence of prominent valves of Kerckring (plicae circulares). 3. The ileum is almost devoid of valves of Kerckring, however large accumulations of lymphatic tissue, both nodular and dense, are found in the lamina propria. These can often be seen macroscopically as large white patches and are commonly known as Peyer's patches. The ilieum is the preferred site for vitamin B12 absorption. Note: The ileum empties into the cecum at the ileocecal junction.

A 15-year-old patient comes into the emergency room with diffuse abdominal pain, loss of appetite, and a fever. On palpation of the lower right abdomen he feels pain, and even greater rebound pain when the pressure is released. The diagnosis is appendicitis. Which of the nine regions of the abdomen contains the appendix? j • Umbilical • Epigastric • Hypogastric • Lumbar • Hypochondriac • Iliac

Iliac The abdomen is divided into nine regions by four imaginary planes "like a tic-tac-toe board". 1. Umbilical -- around the umbilicus; includes portions of the small and large intestines, inferior vena cava, and abdominal aorta. 2. Right and left lumbar -- lateral to umbilical region; contains portions of the small and large intestines and portions of the right and left kidneys. 3. Epigastric -- immediately below the diaphragm and superior to the umbilical region; contains portions of the pancreas and most of the stomach and the liver, inferior vena cava, abdominal aorta, and duodenum. 4. Right and left hypochondriac -- lateral to the epigastric region. Contains portions of the diaphragm, kidneys, and stomach, the spleen, and part of the pancreas. 5. Hypogastric (pubic) -- inferior to the umbilical region; contains the bladder, ureters, and portions of the sigmoid colon and small intestine. 6. Right and left iliac (inguinal) -- lateral to the hypogastric region; contains portions of the small and large intestines.

Parasympathetic Ganglia: location and fibers a. Ciliary b. Pterygopalatine c. Subtnandibular d. Otic

Location: a. Posterior part of the orbit on the lateral side of the optic nerve b. Deeply placed in the pterygopalatine fossa c. Situated on the lateral surface of the hyoglossus muscle d. Situated just below the foramen ovale and is medial to the mandibular nerve Fibers: a• Preganglionic parasympathetic fibers from the oculomotor nerve a• Postganglionic parasympathetic fibers leave ganglion in the short ciliary nerves a• Sympathetic fibers from the internal carotid plexus b• Preganglionic secretomotor fibers arise in the lacrimal nucleus of the facial nerve b• Postganglionic parasympathetic fibers reach the maxillary nerve by one of its ganglionic branches — these reach the lacrimal gland; others run in the palatine and nasal nerves to the palatine and nasal glands b• Sympathetic fibers reach the ganglion via the internal carotid plexus c• Preganglionic parasympathetic fibers reach the ganglion from the superior salivary nucleus of the facial nerve via the chorda tympani and lingual nerves c• Postganglionic parasympathetic fibers pass to the submandibular gland, to which they are secretomotor. Other secretomotor fibers pass to the sublingual gland c• Sympathetic fibers are vasomotor to the blood vessels of the glands d• Preganglionic parasympathetic fibers originate in the inferior salivary nucleus of the glossopharyngeal nerve d• Postganglionic parasympathetic fibers leave the ganglion and join the auriculotemporal nerve, fibers are secretomotor to the parotid gland

Structure and function: CNS • Astrocyte • Oligodendrocytes • Microglia • Ependymal cells • Choroidal cells PNS • Satellite cells • Schwann cells

Structure: Many processes attached to their cell body Smaller cell bodies than astrocytes and relatively fewer processes leaving the cell body Smallest cell bodies among the neuroglia Columnar cells with ciliated free surfaces Modified ependymal cells Small, flattened cells Flattened cells arranged in series around axons Function: Provide structural support Form myelin sheaths around axons in the CNS Main phagocytic cell and antigen-presenting cells in the CNS Line most of the ventricular system of the CNS Form the inner layer of the choroid plexus. Secrete cerebrospinal fluid into the ventricles Support cell bodies in ganglia within the PNS Form myelin within the PNS

All of the longitudinal muscles of the pharynx are innervated by the vagus nerve via the pharyngeal plexus EXCEPT one. Which one is the EXCEPTION? • Stylopharyngeus • Palatopharyngeus • Salpingopharyngeus

Stylopharyngeus *** The stylopharyngeus is innervated by the glossopharyngeal nerve.

atlanto-occipital joint

allows you to nod your head to say "yes". is the synovial articulation between the superior articulating facets of the atlas (first cervical vertebra) and the occipital condyles of the skull

Each respiratory bronchiole subdivides into several

alveolar ducts, which end in clusters of small, thin-walled air spaces called alveoli. These clusters of alveoli are called alveolar sacs and form the functional unit of the lung.

hilum of kidney

an indentation of the medial border through which the ureters renal vessels and nerves enter or leave

urethra

carries urine from the urinary bladder to the outside of the body. In males, the urethra carries semen as well as urine. Note: The portion of the male urethra that passes through the urogenital diaphragm is called the membranous urethra.

red pulp

part of spleen that filters blood and removes abnornmal cells. it consists of BVs(splenic sinusoids) interwoven with CT (splenic cords). contains lymohocytes, macrophages, plasma cells, and monocytes. is the site of erythrypoiesis in fetus and infant.

jugular lymph trunk drainage

drains into either the throacic duct on the left or the right lymphatic duct on the right or independently drains into either the internal jugular, subclavian, or brachiocephalic veins

what happens if you accidently deposit anesthetic solution in the parotid gland when giving a mandibular block?

patient will develop paralysis of muscles of facial expression

hematocrit

proportion of erythrocytes in blood sample...for males 46% and females 40%.

parotid lymph nodes

recieve lymph from: 1)strip of scalp above the parotid salivary glands 2)anterior wall of external auditory meatus 3)lateral parts of eyelids and middle ear the efferent lymph vessels drain into the deep cervical nodes

deep cervical lymph nodes job

responsible for the drainage of most of the circular chain of nodes, and receive direct efferents from salivary and thyroid glands, tongue,tonsils, nose, pharynx and larynx. all of these vessels join to form the jugular lymph trunk

amphiarthrosis

slightly movable, cartiligenous joint. example is the symphysis pubis where the 2 os coxa bones join anteriorly

platelets

small cell fragments whose function is hemostasis...disc like, found in plasma, have no definite nucleus, no DNA, and no hemoglobin. lifespan 7-10 days. removed in the spleen and liver. clot blood by forming platelet plug and contain many secretory vesicles (granules) that promote clotting

joint cavity

small fluid filled space seperating the ends of adjoining bones

Fracture repair involves the following events:

(1) Blood clot formation, (2) Bridging callus formation, (3) Periosteal callus formation, and (4) New endochondral bone formation.

The initiation of bone mineralization involves the following

(1) Holes or pores in collagen fibers. (2) The release of matrix vesicles by osteoblasts. (3) Alkaline phosphatase activity in osteoblasts and matrix vesicles. (4) The degradation of matrix pyrophosphate to release an inorganic phosphate group.

renal calyx of kidney

extension of renal pelvis. minor calyces unite to form major calyces which urine is emptied into

when antigen recognition occurs by a lymphocyte, B cells are activated and migrate to which area of the lymph node

germinal centers

synovial joint classes of joint movement

gliding (plane): include those joints found in the carpal bones of the wrist and the tarsal bones of the ankle hinge: the elbow and knee joints pivot: i.e. between atlas (c1) and axis(c2) of the vertebral column ellipsoid (condyloid): found between the distal surfaces of the forearm bones (radius + ulna) and the adjacent carpal bones Saddle: found where the metacarpal of the thumb meets

name structures of nephron in order they are encountered from blood to urine

glomerulus> bowmans capsule> PCT> loop of henle> DCT> collecting duct

a synarthrosis is an

immovable, fibrous joint. sutures found between the flat bones in skull are of this type.

hemoglobin

in erythrocytes, combine with oxygen to form oxyhemoglobin or with CO2 to make carbaminohemoglobin which is transported to the lungs

where is thoracic duct located and what does it drain

in posterior mediastinum. it begins in the abdomen as a dilated sac called Cisterna Chyli (at the level of T12 vertebra) and ascends through the thoracic cavity in front of the spinal column. its the common trunk of all the lymphatic vessels of the body and drains the lymph from most of the body (legs, abdomen, left side of head, left arm and left thorax)

rank erythrocytes, platelets, and all the leukocytes by greatest number of cells to least

erythrocytes>platelets>leukocytes neutrophils>lymphocytes>monocytes>eosinophils>basophils [Never Let Monkeys Eat Bananas]

Longitudinal Muscles of the Pharynx: Give the Origin, Insertion, Action. Stylopharyngeus Palatopharyngeus Laryngopharynx Salpingopharyngeus

-Styloid process of temporal bone Lateral and posterior pharyngeal walls Elevates the larynx and pharynx during swallowing -Posterior border of the hard palate and from the palatine aponeurosis -Laryngopharynx and thyroid cartilage Pulls the wall of the pharynx up-ward. Acting together, they pull the palatopharyngeal arches to-ward the midline -Lower part of the cartilage of the auditory tube Fibers pass downward and blend with the pala¬topharyngeus muscle Assists in elevating the pharynx

Facial — Cranial Nerve VII, function of each component: -Branchial motor (special visceral efferent) -Visceral motor(general visceral efferent) -General sensory (general somatic afferent) -Special sensory (special afferent)

-Supplies the muscles of facial expression; posterior belly of digastric muscle; stylohyoid, and stapedius muscles -Parasympathetic innervation of the lacrimal, submandibular, and sublingual glands, as well as mucous membranes of the nasopharynx and the hard and soft palate -General sensation from the skin of the concha of the auricle and from a small area behind the ear -Provides taste sensation from the anterior two-thirds of the tongue; hard and soft palates

function of each: Branchial motor (special visceral efferent) Visceral motor(general visceral efferent) Visceral sensory (general visceral afferent) General sensory (general somatic afferent) Special sensory (special afferent)

-Supplies the voluntary muscles of the pharynx and most of the larynx, as well as the palatoglossus muscle of the tongue -Parasympathetic innervation of the smooth muscle and glands of the pharynx, larynx, and viscera of the thorax and abdomen -Provides visceral sensory information from the larynx, esophagus, trachea, and abdominal and thoracic viscera, as well as the stretch receptors of the aortic arch and chemoreceptors of the aortic bodies -Provides general sensory information from the skin of the back of the ear and external auditory meatus, parts of the external surface of the tympanic membrane, and the pharynx -A very minor component of CN X. Provides taste sensation from the epiglottic region

Branchial Arches and Future Nerves and Muscles, Derivative Structures Future Skeletal Structures and Ligaments -First arches (mandibular) -Second arches (hyoid) -Third arches -Fourth through sixth arches

-Trigeminal nerve, muscles of mastication, mylohyoid and anterior belly of digastric, tensor tympani, tensor veli palatine muscles -Facial nerve, stapedius muscle, muscles of facial expression, posterior belly of the digastric muscle, stylohyoid muscle -Glossopharyngeal nerve, stylopharyngeal muscle -Superior laryngeal branch and recurrent laryngeal branch of vagus nerve, levator palatine muscles, pharyngeal constrictors, intrinsic muscles of the larynx -Malleus and incus of middle ear, including anterior ligament of the malleus, sphenomandibular ligament, and portions of the sphenoid bone -Stapes and portions of malleus and incus of middle ear, stylohyoid ligament, styloid process of the temporal bone, lesser comu of hyoid bone, upper portion of body of hyoid bone -Greater comu of hyoid bone, lower portion of body of the hyoid bone -Laryngeal cartilages

Front lobe parts and functions parietal lobe parts and functions occipital lobe parts and functions temperal lobe parts and functions

1) Frontal lobe Is associated with reasoning, motor skills, higher-level cognition, and expressive language Parts: •a Prefrontal area of frontal lobe •b Precentral gyrus of frontal lobe •c Broca's area a. Concerned with the control of social behavior, motivation, and planning b. Primary motor area c. Expression of language 2) Parietal lobe Is associated with processing tactile sensory information such as pressure, touch, and pain •a Postcentral gyrus of parietal lobe •b Near bottom of postcentral gyrus •c Somatosensory cortex a. Primary sensory area b. Primary taste area c. Is essential to the processing of the body's senses 3) Occipital lobe Primary visual area 4) Temporal lobe • Hippocampus Primary auditory cortex, which is important for interpreting sounds and the language we hear. Primary olfactory area (smell). Associated with the formation of memories

Consider the following three tubes [1. epididymis 2. oviduct 3. ejaculatory duc] When a man and a woman are participating in sexual intercourse, name the path the sperm travels upon ejaculation. • 1,3,2 • 3,1,2 • 2,1,3 • 2,3,1

1,3,2 -- epididymis, ejaculatory duct, oviduct Sperm is formed in the testes and then passes along the ductus deferens, which joins the duct of the seminal vesicle to form the ejaculatory duct. During ejaculation, the sperm com¬bines with secretions from the prostate gland and seminal vesicles to form the seminal fluid. The testes are two oval organs contained in the scrotum; the right one is usually higher than the left by nearly a half inch. The testis is capped by the epididymis. The epididymis is a tortuous, C-shaped, cord-like tube about 20 feet long located in the scrotum. The tube emerges from the tail as the ductus (vas) deferens. The ductus deferens and its surrounding vessels and nerves form the spermatic cord, which runs upward to the level of the pubic tubercle of the pubic bone, passes through the inguinal canal, and then turns sharply to enter the pelvic cavity. The ductus deferens then heads toward the back of the prostate gland, where the ductus deferens expands into an ampulla and joins the duct of the seminal vesicle to form the ejaculatory duct. The ejaculatory duct penetrates the prostate gland to open into the prostatic urethra. After leaving the prostate gland, the urethra runs through the muscles of the urogenital diaphragm, and enters the penis. 1. The ejaculatory duct is one of the two passageways that carry semen from the prostate gland to the urethra. The oviduct (fallopian tube) is one of a pair of ducts opening at one end into the uterus and at the other end into the peritoneal cavity, over the ovary. Each tube serves as a passage through which an ovum is carried to the uterus and through which spermatozoa move out toward the ovary. 2. Stereocilia are long, nonmotile microvilli that cover the free surfaces of some of the pseudostratified columnar epithelium that lines the inside of the epididymis. Stereocilia serve to facilitate the passage of nutrients from the epithelium to the sperm by increasing the epithelium's surface area. Note: Stereocilia are also present in the ductus (vas) deferens, which is also lined with pseudostratified columnar epithelium.

Which layer of skin is mainly composed of areolar connective tissue and adipose tissue? • Epidermis • Hypodermis • Dermis

1-lypodermis -- also called the subdermis The integumentary system consists of the skin and its many derivatives (hair, glands, nails, and sensory receptors). The skin is composed of many tissues structurally joined for specific func¬tions. Structure of skin: • The outer epidermis: which consists of stratified squamous epithelium. It develops from embryonic ectoderm. The outer dermis is avascular. The principal cell of the epidermis is called a keratinocyte. The outer dermis consists of four layers. From innermost to outer- most, they are: the stratum germinativum (which has two subdivisions, the stratum basale and stratum spinosum), stratum granulosum, stratum lucidum, and stratum come= • The inner dermis: thicker portion of the skin; composed of connective tissue with col-lagenous and elastic fibers for toughness. The inner dermis develops from embryonic meso¬derm and contains blood vessels, nerves, glands, and hair follicles. It is a strong, stretchable layer that essentially holds the body together. The inner dermis has two main regions: • papillary layer: upper dermal region • reticular layer: deepest skin layer *** The subdermis (hypodermis) is the layer of tissue directly underneath the dermis. The sub- dermis is mainly composed of areolar (loose) connective tissue and adipose tissue. The sub- dermis's physiological functions include insulation, the storage of energy, and aid in the anchoring of the skin. The subdermis also cushions the underlying body for extra protection against trauma. The skin also contains several other relevant structures, including the following: • Basement membrane: collagenous membrane between the epidermis and dermis that holds them together • Meissner's corpuscle: oval body in the dermis, thought to participate in tactile sensation • Ruffini's corpuscle: oval capsule containing the ends of sensory fibers in the dermal papillae

Listed below are the usual events in the histogenesis of a tooth. Place them in their correct sequence (from what happens first to what happens last). • Deposition of the first layer of dentin • Differentiation of odontoblasts • Deposition of the first layer of enamel • Elongation of inner enamel epithelial cells

1. Elongation of the inner enamel epithelial cells of the enamel organ; this influences mesenchymal cells on the periphery of the dental papilla to differenti¬ate into odontoblasts (#2 below) 2. Differentiation of odontoblasts 3. Deposition of the first layer of dentin 4. Deposition of the first layer of enamel Tooth development is dependent on a series of sequential cellular interactions between epithelial and mesenchymal components of the tooth germ. Once the ectomesenchyme influences the oral epithelium to grow down into the ectomes¬enchyme and become a tooth germ, the above events occur. 1. Some texts include the deposition of root dentin and cementum as #5 in the histogenesis of a tooth. 2. Korff's fibers is a name given to the rope-like grouping of fibers in the periphery of the pulp that seem to have something to do with the formation of dentin matrix. Remember: Histogenesis means the formation and development of the tissues of the body, in this case the tooth.

meniscus

10% of synovial joints have a washer-like structure between bone ends called the meniscus. its job is to absorb shock, stabilize joint, and spread synovial fluid. its made of fibrocartilage, but doesnt have blood supply, nerves, or lymphatic channels, so it cant heal itself. knee meniscus it the one that always gets ****ed up in athletes

What percent of mature enamel is not inorganic hydroxyapatite? • 4% • 10% • 16% • 25%

4% Enamel is a highly mineralized structure containing approximately 96% inorganic material. This inorganic component consists of mainly (90-95%) calcium hydroxyapatite with the chemical formula of Ca10(PO4)6(OH)2. Other minerals, such as carbonate, magnesium, potassium, sodium, and fluoride, are also present in smaller amounts. Note: Due to the high inorganic content, enamel appears optically clear on a histologic section of the human tooth. Enamel also consists of an organic matrix (1%) and water (3%). This organic matrix and water content decreases as enamel matures. At the same time, the inorganic content increases. Enamel is semitranslucent and turns various shades of yellow-white because of the underlying dentin. The enamel on primary teeth has a more opaque crystalline form and thus appears whiter than on permanent teeth. Note: Enamel is a selectively permeable membrane, allowing water and certain ions to pass via osmosis.

How is most CO2 in the blood transported as?

70% of CO2 transported by blood as bicarbonate ion (the rest transported as carbaminohemoglobin etc)

Bronchioles are characterized by:

A diameter of one millimeter or less An epithelium that progresses from ciliated pseudostratified columnar to simple cuboidal (respiratory bronchioles) Small bronchioles have non-ciliated bronchiolar epithelial cells (Clara cells) that secrete a surface-active lipoprotein Walls devoid of glands in the underlying connective tissue

sinusoid

A sinusoid is a small blood vessel similar to a capillary but with a discontinuous endothelium. Sinusoids are found in the liver, lymphoid tissue, endocrine organs, and hematopoietic organs such as the bone marrow and the spleen. Sinusoids: Are 30 to 40 microns in diameter. Are wider and more irregular than capillaries. Have walls that consist largely of phagocytic cells. Form a part of the reticuloendothelial system, which is concerned chiefly with phagocytosis and antibody formation

A tubercle is:

A small, rounded process

An endodontist is performing root canal therapy on his anxious dental patient. His anesthesia has been successful throughout the access preparation, cleaning, and shaping. Just before he starts to obdurate, he sticks a paper point in the first canal to dry it out. The patient jumps up in pain from the stimulus. Which type of primary afferent fiber carries information related to sharp pain and temperature? • A-alpha fibers • A-beta fibers • A-delta fibers • C-nerve fibers

A-delta fibers Primary afferent axons are the nerve fibers connected to the different types of receptors in the skin, muscle, and internal organs. These primary afferent axons come in different diameters and can be divided into different groups based on their size. Here, in order of decreasing size, are the different nerve fiber groups: A-alpha, A-beta, A-delta, and C-nerve fibers. A-alpha, A-beta, and A-delta nerve fibers are insulated with myelin. C-nerve fibers are unmyelinated. The thickness of the nerve fiber is correlated to the speed with which information travels in it -- the thicker the nerve fiber, the faster information travels in it. Important: • A-alpha nerve fibers carry information related to proprioception (muscle sense) • A-beta nerve fibers carry information related to touch • A-delta nerve fibers carry information related to pain and temperature • C-nerve fibers carry information related to pain, temperature, and itch Autonomic neurotransmitters: • All autonomic preganglionic synapses have Ach as the neurotransmitter (nicotinic receptors) • All postganglionic parasympathetic synapses have Ach as the neurotransmitter (muscarinic receptors) • Most postganglionic sympathetic synapses have NE as the neurotransmitter (adren¬ergic receptors) • Sympathetic preganglionic neurotransmitter at adrenal medulla is Ach (nicotinic receptor) -- release of epinephrine and norepinephrine (80/20) • Sympathetic postganglionic neurotransmitter at sweat glands is Ach (muscarinic re¬ceptors)

a The trapezius and sternocleidomastoid muscles receive motor innervation from the: • Glossopharyngeal nerve (CN IX) • Vagus nerve (CN X) • Accessory nerve (CN XI) • Hypoglossal nerve (CN XII)

Accessory nerve (CN XI) (see chart 240)

A 62-year-old female patient with osteoarthritis is having her right hip replaced. A titanium-ceramic prosthesis will act as the head of her femur and a poly-ethylene cup will act as the socket in the hip bone. In a normal hip, this cup-shaped cavity that receives the head of the femur is called the: • Pubic tubercle • Obturator foramen • Acetabulum • Pelvic girdle

Acetabulum The os coxa or hipbone is formed by the fusion of the ilium, ischium, and pubis on each side of the pelvis. The os coxa articulates with the sacrum at the sacroiliac joint to form the pelvic girdle. The two hip bones articulate with one another anteriorly at the symphysis pubis. • The ilium is the upper flattened part of the hip bone; the ilium possesses the iliac crest, which ends in front at the anterior superior iliac spine and behind at the post-erior superior iliac spine. The ilium possesses a large notch called the greater sciatic notch. • The ischium is L-shaped with an upper thicker part (body) and a lower thinner part (ramus). This part bears the weight of the body when a person is in an upright, seated position. Features include ischial spine and ischial tuberosity. The obturator foramen is formed by the ramus of the ischium together with the pubis. • The pubis is divided into a body, a superior ramus, and an inferior ramus. The bodies of the two pubic bones articulate with each other in the midline anteriorly at the symphysis pubis. Medial to the symphysis is the pubic tubercle. The inguinal ligament connects the pubic tubercle to the anterior superior iliac spine. Note: The acetabulum is a cup-shaped cavity on the lateral side of the hip bone that receives the head of the femur. It is formed superiorly by the ilium, posteroinferiorly by the ischium, and anteromedially by the pubis.

Action: Pectoralis major Pectoralis minor Latissimus dorsi Deltoid Teres major Teres minor

Adducts the arm and rotates it medially Pulls the shoulder downward and forward Extends, adducts, and medially rotates the arm With the help of the supraspinatus muscle, it abducts the upper limb at the shoulder joint Medially rotates and adducts the arm Laterally rotates the arm and stabilizes the shoulder joint

The part of a developing salivary gland destined to become responsible for its functioning is called the: • Nephron • Follicle • Adenomere • Lobule

Adenomere -- it is the functional unit in salivary glands Exocrine glands are structurally and functionally subdivided by septa, plate-like invaginations of their connective tissue capsules. This arrangement applies mainly to the pancreas and sali¬vary glands. 1. Lobes are the largest of the subunits and are separated by connective tissue septa. 2. Lobules are subunits of the lobes and are separated by thin extensions of the septa. 3. Adenomeres are secretory subunits of lobules. Adenomeres consist of all the secretory cells that release their products into a single intralobular duct. 4. Acini (or alveoli) are smaller secretory subunits. Each acinus is a spheric collection of secretory cells surrounding the blind-ended termination of a single intercalated duct. An adenomere is composed of: • Intercalated ducts -- transport saliva to larger ducts • Striated ducts -- contain a lot of mitochondria responsible for electrolyte and water transport during secretion. Simple, low columnar epithelium line these ducts • Glandular cells -- synthesize glycoproteins Types of salivary glands: • Major 1. Parotid gland -- purely serous gland 2. Submandibular (submaxillary) gland -- mixed serous and mucous gland 3. Sublingual gland -- purely mucous gland • Minor are located on the: 1. Lips 2. Cheek 3. Tongue -- von Ebner's glands are associated with circumvallate papilla 4. Hard palate

A death-row inmate who was notorious for aggressive and hyperactive behavior is complaining of abdominal pain. Hospital tests reveal bilateral tumors that are secreting excessive catecholamines. The pheochromocytomas are located on which endocrine gland? j • Anterior pituitary • Pancreatic islets (Langerhans) • Adrenal medulla • Parathyroids • Adrenal cortex

Adrenal medulla Stimulation of the adrenal medulla causes the release of large quantities of epinephrine and norepinephrine. The same effects are also caused by direct sympathetic stimulation, ex¬cept the effects last longer when the medulla secretes the hormones. With or without one or the other (medulla or sympathetic nerves), the organs would still be stimulated. In other words, the medulla functions in a manner similar to postganglionic sympathetic cells. The two adrenal glands (also called suprarenal glands) are flattened, somewhat triangular-shaped endocrine glands resting upon the superior poles of each kidney at the back of the ab¬domen. Each gland has an outer part, the cortex, and a core, the medulla. The adrenal cortex produces three main types of hormones: • Glucocorticoids: which are produced and released under the control of adrenocorti-cotrophic hormone (ACTH) from the pituitary, influences the metabolism of fat, protein, and carbohydrates, promoting the breakdown of protein and the release of fat and sugars into the bloodstream • Mineralocorticoids: stimulate the release of sodium in the kidneys • Sex steroids The adrenal medulla contains many modified nerve cells, which produce the hormones ep¬inephrine and norepinephrine (adrenaline and noradrenaline). These hormones are re-leased in bursts during emergency situations or accompanying intense emotion. They act to increase the strength and rate of heart contractions, raise the blood sugar level, elevate the blood pressure, and increase breathing. Important: The adrenal medulla develops from neuroectoderm, while the adrenal cortex develops from mesoderm. Note: Neuroectoderm is a specialized group of cells that differentiate from the ectoderm. Neural crest cells are a specialized group of cells developed from neuroectoderm that migrate from the crests of the neural folds and disperse to specific sites within the mes-enchyme. They also influence a special type of mesenchyme, the ectomesenchyme, to form dental tissues.

A young girl presents to the physician with a large, round face, a "buffalo hump," and central obesity. She also has a history of hypertension and insulin resistance as a result of increased cortisol from Cushing's syndrome. Which anterior pituitary hormone controls the production and secretion of glucorticoids such as cortisol? • Follicle-stimulating hormone (FSH) • Luteinizing hormone (LH) • Adrenocorticotropic hormone (ACTH) • Thyroid-stimulating hormone (TSH)

Adrenocorticotropic hormone (ACTH) -- also called corticotropin Adrenocorticotropic hormone, as its name implies, stimulates the adrenal cortex. More specifically, this hormone stimulates secretion of glucocorticoids such as cortisol, and has little control over secretion of aldosterone, the other major steroid hormone from the adrenal cortex. ACTH is secreted from the anterior pituitary in response to corticotropin-releasing hor-mone from the hypothalamus. Corticotropin-releasing hormone is secreted in response to many types of stress, which makes sense in view of the "stress management" functions of glucocorticoids. Corticotropin-releasing hormone itself is inhibited by glucocorticoids. Follicle-stimulating hormone (FSH): • In females, FSH initiates ovarian follicle development and secretion of estrogens in the ovaries • In males, FSH stimulates sperm production in the testes (spermatogenesis) Luteinizing hormone (LH): • In females, LH stimulates secretion of estrogen by ovarian cells to result in ovula¬tion and stimulates formation of the corpus luteum and secretion of progesterone • In males, LH stimulates the interstitial cells of the testes to secrete testosterone Thyroid-stimulating hormone (TSH) regulates thyroid gland activities, uptake of iodine, and synthesis and release of thyroid hormones.

main trunk of the facial nerve

After the main trunk of the facial nerve exits from the stylomastoid foramen, it enters into the substance of the parotid gland. It is here that it gives off five main branches that will supply motor innervation to the muscles of facial expression.

The exchange of oxygen and carbon dioxide between the air and the blood occuring in the lungs. Describe the process

Air enters the mouth or nose and passes into the pharynx and the larynx, and then into the trachea. As the trachea passes behind the arch of the aorta, the trachea bifurcates or divides into a right and left primary or main bronchus, which leads to the lungs. After entering each lung, the trachea bifurcates into right and left primary bronchi at the level of the two main bronchi, which branch into the five lobar bronchi (secondary bronchi). Note: The right main bronchus divides into three lobar bronchi, and the left main bronchus divides into two lobar bronchi. Each secondary or lobar bronchus serves one of the five lobes of the two lungs. Each lobar bronchus enters a lobe in each lung (two lobes on the left, three lobes on the right). Within its lobe, each of the secondary bronchi (lobar bronchi) branch into tertiary bronchi (segmental bronchi). These tertiary bronchi continue to divide deeper in the lungs into tiny bronchioles, which subdivide many times, forming terminal bronchioles. Each of these terminal bronchioles gives rise to several respiratory bronchioles

Nose

Air enters through the nostrils (external nares) that lead to the vestibules of the nose. The bony roof of the nasal cavity is formed by the cribriform plate of the ethmoid bone. The lateral walls have bony projections called conchae (superior, middle, and inferior), which are also referred to as the nasal turbinates. These conchae form shelves that have spaces (or grooves) beneath them called meatuses (superior, middle, and inferior). The paired paranasal sinuses (maxillary, frontal, ethmoidal, and sphenoidal) drain into the nasal cavity by way of these meatuses. The nasolacrimal duct, which drains tears from the surface of the eyes, also empties into the nasal cavity by way of the inferior meatus. The floor is formed by the hard palate. The nasal cavity opens posteriorly into the nasopharynx via funnel-like openings called the choanae (posterior nares).

The periodontal ligament space is vital to the functional life of the tooth because this space: • Contains nervous and vascular elements • Allows for physiologic movement of the tooth • Provides a cellular source for new cementum and bone • All of the above

All of the above Functions of the PDL: • Support: provides attachment of the tooth to the alveolar bone • Formative: contains cells responsible for formation of the periodontium • Nutritive: contains a vascular network providing nutrients to its cells • Sensory: contains afferent nerve fibers responsible for pain, pressure, and proprio¬ception • Remodeling: contains cells responsible for remodeling of the periodontium Important: Orthodontic treatment is possible because the PDL continuously responds and changes as the result of the functional requirements imposed upon the PDL by externally applied forces. Contents of the PDL: • Fibroblasts: like all connective tissues, they are the most common cell • Cementoblasts and cementoclasts • Osteoblasts and osteoclasts • Macrophages, mast cells, and eosinophils • Undifferentiated mesenchymal cells • Ground substance: proteoglycans, glycosaminoglycans, glycoproteins, and water The PDL has a vascular supply (arises from the maxillary artery), lymphatics ( drain to the submandibular lymph nodes), and a nerve supply, which enter the apical foramen of the tooth to supply the pulp. Two types of nerves are found within the PDL: 1. One type is afferent, or sensory, which is myelinated and transmits sensation. 2. The other type is autonomic sympathetic, which regulates the blood vessels. Two types of nerve endings are found in the PDL: 1. Free nerve endings; convey pain. 2. Encapsulated nerve endings; convey pressure.

celiac artery

All of the arteries that supply the stomach are derived directly or indirectly from the celiac trunk (celiac artery). The celiac artery takes its origin from the abdominal aorta just below the diaphragm at about the level of the twelfth thoracic vertebra. It is the artery that supplies the foregut. The celiac artery is surrounded by the celiac plexus and lies behind the lesser sac of peritoneum. The celiac artery has three terminal branches: the splenic, left gastric, and hepatic arteries.

The lamina dura is the hard layer of bone surrounding the periodontal ligament along the roots of teeth. The lamina dura is a component of which of the following? • Alveolar bone proper • Supporting alveolar bone • Alveolar crest • Cortical plate

Alveolar bone proper The alveolar process is that part of the maxilla and mandible that forms and supports the sockets of the teeth. Like all bone, mature alveolar bone is by weight 60% mineralized, or in¬organic material, 25% organic material, and 15% water. The inorganic component consists of mainly calcium hydroxyapatite with the chemical formula of Cal o(PO4)6(OH)2. This calcium hydroxyapatite is similar to that found in higher percentages in enamel and dentin and is most similar to that of cementum. The alveolar process consists of two main parts: 1. Alveolar bone proper -- is a thin layer of compact bone that is a specialized continua-tion of the cortical plate and forms the tooth socket or alveolus. Note: The lamina dura is a horseshoe-shaped white line on a dental radiograph that roughly corresponds to the alve¬olar bone proper. The lamina dura has minute openings that provide passages for vascular and nerve components. It is composed of compact bone, but is sometimes called bundle bone due to the presence of bundles of perforating Sharpey's fibers. 2. Supporting alveolar bone -- that bone that surrounds the alveolar bone proper and gives support to the socket. It consists of • Cortical plate -- Structurally, the cortical plate is composed of lingual and facial plates of compact bone. The cortical plate is dense in nature and provides strength and protection and acts as the attachment for skeletal muscles. The mandibular cortical plate is more dense than the maxillary cortical plate and has fewer perforations for the passage of nerves and blood vessels. Note: The alveolar crest is the highest point of the alveolar ridge and joins the facial and lingual cortical plates. • Spongy bone (cancellous bone) -- fills in the area between cortical plates and alveolar bone proper. This type of bone is not present in the anterior region of the mouth; here the cortical plate is fused to the alveolar bone proper. This is also true over the radicular buc cal bone of the maxillary posteriors. Note: The alveolar bone proper is the only essential part of the bone socket. The sup-porting alveolar bone is not always present.

emergency tracheotomy

An emergency tracheotomy (tracheostomy) is most easily made by an incision through the median cricothyroid ligament. This ligament runs from the cricoid cartilage to the thyroid cartilage and is inferior to the space between the vocal cords (rima glottidis) where aspirated objects usually get lodged. The tracheotomy allows for air to pass between the lungs and the outside air. Important: The space entered is called the cricothyroid space. Note: A tracheotomy (tracheostomy) is rarely performed and is limited to patients with extensive laryngeal damage and infants with severe airway obstruction. Because of the presence of major vascular structures (carotid arteries and internal jugular vein), the thyroid gland, nerves (recurrent laryngeal branch of the vagus nerve), the pleural cavities, and the esophagus, meticulous attention to anatomical detail has to be observed.

Function: Plasma Mast Schwann Sertoli Leydig Fibroblast Osteoblast Odontoblast Ameloblast T (Lymphocytes) B (Lymphocytes) Alpha (Pancreatic) Beta (Pancreatic)

Antibody synthesis Mediator of inflammation on contact with antigen Forms myelin sheath around axons of the PNS Produces testicular fluid Produces testosterone Produces collagen and reticular fibers Forms bone matrix, gives rise to osteocytes Forms dentin Forms enamel Cell-mediated immunity Differentiate into plasma cells Produces glucagon Produces insulin

A lesion of the facial nerve just after it exits from stylomastoid foramen would result in: • An ipsilateral (same side) loss of taste to the anterior tongue • A decrease in saliva production in the floor of the mouth • A sensory loss to the tongue • An ipsilateral (same side) paralysis of facial muscles • A contralateral (opposite side) paralysis of facial muscles

An ipsilateral (same side) loss of taste to the anterior tongue The facial nerve is the nerve of facial expression. The facial nerve is a mixed nerve containing both sensory and motor components. It emerges from the brainstem between the pons and the medulla, and controls the muscles of facial expression, and taste to the anterior two-thirds of the tongue. The facial nerve's main function is motor control of most of the facial muscles and muscles of the inner ear. This nerve also supplies parasympathetic fibers to the submandibular gland and sublingual glands via the chorda tympani nerve and the submandibular ganglion, and to the lacrimal gland via the pterygopalatine ganglion. In addition, the nerve receives taste sensations from the anterior two-thirds of the tongue. The facial nerve has four components with distinct functions: Key point: Branchial motor fibers constitute the largest portion of the facial nerve. The remaining three components are bound in a distinct fascial sheath from the branchial motor fibers. Collectively, these three components are referred to as the nervus intermedius.

The external carotid has eight branches that mainly supply head structures outside the cranial cavity. The branches are as follows:

Anterior branches: Superior thyroid artery, Lingual artery, Facial artery, Maxillary artery Posterior branches: Posterior auricular artery, Occipital artery, Ascending pharyngeal artery, Superficial temporal artery

In an elderly adult, the thymus is mostly atrophied, and the remains lie in the superior mediastinum. In a pubescent boy, the thymus is at its largest, with an average mass of 35 grams. When it is this size, the thymus will be present in which other division of the mediastinum? • Anterior mediastinum • Middle mediastinum • Posterior mediastinum

Anterior mediastinum The thoracic cavity is surrounded by the ribs and chest muscles. It's subdivided into the pleural cavities, each of which contains a lung, and the mediastinum, which contains the heart, large vessels of the heart, trachea, esophagus, thymus, lymph nodes, and other blood vessels and nerves. The mediastinum is further divided into four areas. Listed below are some of the major structures contained within the different regions. (It is not within the scope of these cards to list all of the contents of the mediastina). Note: Some structures overlap into different areas. • Superior mediastinum -- arch of the aorta, left and right subclavian arteries and veins, right and left common carotid arteries, right and left internal jugular veins, right and left brachiocephalic veins, brachiocephalic artery, upper half of the superior vena cava, right and left primary bronchus, trachea, esophagus, thoracic duct, thymus, the phrenic nerves, vagus nerves, cardiac plexus of nerves, and left recurrent laryngeal nerve • Inferior mediastinum -- region directly below the superior mediastinum. This is sub¬divided into three regions: anterior, middle, and posterior 1. Anterior mediastinum -- lymph nodes, branches of internal thoracic artery; in children, contains the inferior part of the thymus gland. 2. Middle mediastinum -- pericardium, heart and adjacent great vessels, the phrenic nerves, and the main bronchi. 3. Posterior mediastinum -- thoracic aorta, thoracic duct, esophagus, trachea, right and left main bronchus, brachiocephalic artery, left common carotid artery, left sub¬clavian artery, arch of aorta, esophageal plexus (branches of vagus and splanchnic nerves), sympathetic chain ganglia, azygos and hemiazygos veins, and many lymph nodes.

The greatest drop in blood pressure is seen at the transition from:

Arteries to arterioles. Important: The highest pressure of circulating blood is found in arteries, and gradually drops as the blood flows through the arterioles, capillaries, venules, and veins (where it is the lowest). The greatest drop in blood pressure occurs at the transition from arteries to arterioles.

Which of the following are considered to be primary resistance vessels? ) • Large arteries • Arterioles • Capillaries • Large veins

Arterioles (see chart 320) 1. Veins have thinner walls than arteries but have larger diameters because of the Notes low blood pressures required for venous return to the heart. 2. Valves in the veins of the neck, arms, and legs prevent venous backflow. 3. Important: With the exception of the pulmonary vessels and certain fetal vessels, arteries transport oxygenated blood, and veins transport deoxygenated blood. 4. Venules continue from capillaries and merge to form veins.

Arterioles

Arterioles have a very small diameter (<0.5 mm), a small lumen, and a relatively thick tunica media that is composed almost entirely of smooth muscle, with little elastic tissue. This smooth muscle constricts and dilates in response to neurochemical stimuli, which in turn changes the diameter of the arterioles. This causes profound and rapid changes in peripheral resistance. This change in diameter of the arterioles regulates the flow of blood into the capillaries. Note: By affecting peripheral resistance, arterioles directly affect arterial blood pressure.

parts of aorta

Ascending aorta: a short vessel that starts at the aortic opening of the left ventricle. The ascending aorta's only branches are the right and left coronary arteries, which supply the heart muscle. Aortic arch: gives rise to three arterial branches: the brachiocephalic, the left common carotid, and the left subclavian. These arteries furnish all of the blood to the head, neck, and upper limbs. Descending aorta: a) Thoracic portion: extends from T4 to T12 (lies in the posterior mediastinum). All of the arterial branches (posterior intercostal, subcostal arteries) from this part are small. They supply the thorax and the diaphragm. b) Abdominal portion: extends from T12 to L4, where the descending aorta terminates by dividing into the two common iliac arteries and a small middle sacral artery. Arteries from this area supply the abdomen and pelvic region as well as the lower limbs.

When the SA node fails, or the SA node impulse is blocked, which structure must take over as the pacemaker for the heart? • Sinoatrial node • Atrioventricular bundle • Purkinje fibers • Atrioventricular node

Atrioventricular node The heart contains masses of nodal tissue, excitable tissue that conducts impulses and stimulates the heartbeat intrinsically. This conduction system signals the heart to beat in¬dependently. It does not require any external influences. The impulse to stimulate the heartbeat passes through the conduction system structures in this order: SA node -- AV node — AV bundle -- Purkinje fibers. The SA node is in the wall of the right atrium, near the entrance of the superior vena cava. The SA node typically depolarizes spontaneously at the rate of 60 to 100 times per minute, causing the atria to contract. Impulses from the SA node pass to the atrioventric¬ular node (AV node), atrioventricular bundle (AV bundle, or bundle of His), and finally to the conduction myofibers (Purkinje fibers) within the ventricular walls. Stimulation of the conduction myofibers causes the ventricles to contract simultaneously. 1. The rate of the discharge of the SA node sets the rhythm of the entire heart. 2. The rhythm originates from the SA node because the SA node depolarizes more frequently (60-100 beats per minute) than the AV node (40-60 beats per minute) and ventricular conducting system (30-40 beats per minute) so the AV node and ventricular conducting system are "captured" by the sinus impulse and driven at 60-100 beats per minute. 3. In sinus rhythm, every P-wave is followed by a QRS complex, the R-R in¬terval is regular, and the P-R interval is less than 0.2 seconds. A fast sinus rhythm, faster than 100 beats a minute, is known as sinus tachycardia while a slow rhythm, slower than 60 beats a minute, is known as sinus bradycardia.

A college professor has taken a week off with a bad upper respiratory infection that will not resolve. At the end of the week, he has an earache in his left ear, and his hearing is slightly muffled. How would an infection spread from the nasopharynx to the middle ear? • Vestibular apparatus • Auditory tube • External acoustic (auditory) meatus • Acoustic apparatus

Auditory tube -- also called the pharyngotympanic tube, eus achian tube The auditory tube equalizes air pressure on either side of the tympanic membrane. The middle ear communicates posteriorly with the mastoid air cells and the mastoid antrum through the aditus ad antrum. The ear consists of: • External ear -- consists of the auricle (pinna) and the external auditory canal. This part receives sound waves. The auricle consists of cartilaginous antihelix, crux of the helix, lobule, tragus, and concha. The external auditory canal is a narrow chamber measuring about 1 inch long. This canal connects the auricle with the tympanic membrane in the middle ear. • Middle ear (tympanic cavity) -- an air-filled cavity within the petrous part of the temporal bone. The middle ear contains three small bones or ossicles, the malleus (hammer), stapes (stirrup), and incus (anvil) that transmit sound. Lined with mucosa, the middle ear is bound¬ed laterally by the tympanic membrane and medially by the oval and round windows. Also contains two muscles -- the stapedius muscle, which is the smallest of the skeletal muscles in the body, and the tensor tympani muscle. The tympanic membrane, consisting of layers of skin, fibrous tissue, and mucous membrane, transmits sound vibrations to the internal ear. • Inner ear -- consists of closed, fluid-filled spaces within the temporal bone. The inner ear is a bony labyrinth, which includes three connected structures -- the vestibule, the semi¬circular canals, and the cochlea. These structures are lined with a serous membrane that forms the membranous labyrinth. A fluid called perilymph fills the space between the bony labyrinth and the membranous labyrinth. Note: Within the cochlea lies the cochlear duct, a triangular, membranous structure housing the organ of Corti. The receptor organ for hear¬ing, the organ of Corti transmits sound to the cochlear branch of the acoustic (CN VIII) nerve. Clinical considerations: Middle ear infections (otitis media) are quite prevalent and may become extensive due to connections between the tympanic cavity and both the mastoid air cells and the nasopharynx.

Your most recent patient presents to your office complaining of severe pain in his jaws around the temporomandibular (TMJ) joint. He chews three packs of gum a day, and his wife tells him he grinds his teeth at night. What nerve provides major sensory innervation to the TMJ? • Masseteric nerve • Auriculotemporal nerve • Facial nerve (CN VII) • Trochlear nerve (CN IV)

Auriculotemporal nerve The auriculotemporal nerve arises from the posterior division of the mandibular nerve (V-3). The auriculotemporal nerve supplies the posterior portion of the TMJ. The nerve to the masseter (masseteric nerve), also a branch of V-3, carries a few sensory fibers to the anterior portion of the TMJ. The deep temporal nerves (anterior, middle, and posterior branches) innervate the temporalis muscle and carry a few fibers to the an¬terior portion of the TMJ as well. 1. Pain impulses from a patient's fractured condylar neck are carried by the au¬riculotemporal nerve. 2. Pain (TMJ patient) is transmitted in the capsule and periphery of the disc by the auriculotemporal nerve. 3. The auriculotemporal nerve carries some secretory fibers from the otic gan¬glion to the parotid salivary gland. 4. The TMJ, as is the case with all joints, receives no motor innervation. The muscles that move the joint receive the motor innervation. 5. Its arterial blood supply is provided by the superficial temporal and maxil¬lary branches of the external carotid artery.

A student dozing off in class is unexpectedly called on by the professor to answer a question. Not knowing the answer, the hair on the back of the student's neck stands up, his pupils dilate, and his heart starts to race. This fight-or-flight response is controlled by the: • Somatic nervous system • Autonomic nervous system • Skeletal division • Sensory nervous system

Autonomic nervous system The central nervous system includes the brain and spinal cord. The peripheral nervous sys-tem consists of all body nerves. Motor neuron pathways are of two types: somatic (skeletal) and autonomic (smooth muscle, cardiac muscle, and glands). The autonomic system is sub¬divided into the sympathetic and parasympathetic systems. The PNS consists of all nervous structures located outside the CNS. The PNS includes the cra¬nial nerves, arising from the inferior aspect of the brain, and the spinal nerves, arising from the spinal cord. The PNS is divided functionally into afferent (sensory) and efferent (motor) di¬visions. • The afferent division of the PNS includes somatic sensory neurons which carry im-pulses to the CNS from the skin, fascia, and joints, along with visceral sensory neurons, which carry impulses from the viscera of the body (hunger pangs, blood pressure) to the CNS • The efferent division of the PNS is divided into the somatic (voluntary) and autonomic (involuntary) nervous system

Each subclavian vein is a continuation of the and runs from the outer border of the first rib to the medial border of the scalenus anterior musclevi I • Brachial vein • Brachiocephalic vein • Internal jugular vein • Axillary vein

Axillary vein The subclavian veins are two large veins, one on either side of the body. Each subclavian vein begins at the outer border of the first rib as a continuation of the axillary vein. At the medial border of the scalenus anterior, the vein joins the internal jugular vein to form the brachiocephalic vein. Important: The subclavian vein crosses the first rib anterior to the scalenus anterior muscle. The external jugular vein lies in the superficial fascia deep to the platysma. The vein passes downward from the region of the angle of the mandible to the middle of the clavicle. This vein perforates the deep fascia just above the clavicle and drains into the subclavian vein. 1. The subclavian vein follows the subclavian artery and is separated poster-'Notes iorly by the insertion of scalenus anterior muscle. 2. The thoracic duct usually drains into the junction of the left internal jugu¬lar and subclavian veins. 3. Brachial vein -- drains venous blood from deep antebrachial regions and brachial regions into the axillary vein. 4. Cephalic vein -- drains venous blood from the radial side to the antebrachium and brachium into the axillary vein. 5. Brachiocephalic vein -- either of two veins (right and left) formed by the union of the internal jugular and subclavian veins. 6. Superior vena cava -- a large vein formed by the union of the two brachiocephalic veins; this vein has no valves. It receives blood from the head, neck, upper limbs, and chest and empties into the right atrium of the heart. 7. The inferior vena cava (larger than the superior vena cava) opens into the lower part of the right atrium; the inferior vena cava is guarded by a rudiment¬ary, non-functioning valve. The inferior vena cava returns blood to the heart from the lower half of the body.

Which structural component of a neuron sends impulses away from the cell body? • Neuroglial cell • Perikaryon • Dendrite • Axon

Axon Nervous tissue is composed of two types of cells: 1. Neurons -- transmit nerve impulses. 2. Neuroglial cells (glial cells) -- are non-ducting "support cells" of nervous tissue. Examples include astrocytes, attached to the outside of a capillary blood vessel in the brain, phagocytic microglial cells, and ciliated ependymal cells that form a sheath that usually lines fluid cavities in the brain. Structure of a neuron: • Cell body (perikaryon) -- contains the nucleus and most of the cytoplasm. Located mostly in the central nervous system as clusters called nuclei, some found in the pe-ripheral nervous system as groups called ganglia. • Dendrites -- neuronal processes that send the impulse toward the cell body. There may be one or many dendrites per cell. Some neurons lack dendrites. • Axon (nerve fiber) -- neuronal process that sends the impulse away from the cell body. *** If the axon is covered with a fatty substance called myelin, the axon is referred to as a myelinated fiber. If there is no myelinated cover, then the axon is referred to as an un¬myelinated fiber. Neurons are classified according to structure (based on the number of processes that ex¬tend from the cell body): bipolar, unipolar, or multipolar (most common). They are also classified according to function: motor (efferent), sensory (afferent), or interneurons (which lie between sensory and motor neurons in the CNS). Note: Whether or not someone feels different stimuli (pain, temperature, pressure, etc) is determined by the specific nerve fiber stimulated.

Which of the following is the distinctive array of microtubules in the core of cilia and flagella composed of a central pair surrounded by a sheath of nine doublet microtubules (characteristic "9 + 2" pattern)? • Centriole • Axoneme • Tubulin • Malleolus

Axoneme An axoneme is the core scaffold of the eukaryotic cilia and flagella, which are projections from the cell made up of microtubules. Thus, the axoneme serves as the "skeleton" of these organelles, both giving support to the structure and, in most cases, causing it to bend. Though dis¬tinctions of function and/or length may be made between cilia and flagella, the internal structure of the axoneme is common to both. The characteristic feature of the axoneme is its "9 + 2" arrangement of microtubules and associ¬ated proteins, as shown in the image below. Nine pairs of "doublet" microtubules, a component of the cellular cytoskeleton, form a ring around a "central pair" of single microtubules. Ciliary dynein arms, the motor complexes that allow the axoneme to bend, are anchored to these micro-tubules. The interactions between the ciliary dynein proteins and outer doublet microtubules gen¬erate force by sliding the doublets parallel to each other, which bends the cilium and enables it to beat. The radial spoke, a protein complex important in regulating the motion of the axoneme, is also housed in the axoneme; it projects from each set of outer doublets toward the central micro-tubules. The radial spoke is a multi-unit protein structure found in the axonemes of eukaryotic cilia and flagella. The doublets and central sheaths are linked by proteins known as nexins. Note: Centrioles are cell organelles that constitute the centrosome and thus aid in formation of the mitotic spindle.

Most posterior intercostal veins empty into the , which in turn empties into the at the fourth thoracic vertebra. • Femoral vein; inferior vena cava • Subclavian vein; brachiocephalic vein • Azygos venous system; superior vena cava • Splenic vein; hepatic portal system

Azygos venous system; superior vena cava The internal jugular and subclavian veins of each side join at the first intercostal cartilage to form the superior vena cava. An intercostal vein runs alongside each intercostal artery. Each side has eleven posterior intercostal veins and one subcostal vein. Most posterior inter¬costal veins empty into the azygos venous system, which in turn empties into the superior vena cava at the fourth thoracic vertebra. The azygos veins consists of the main azygos vein, the inferior hemiazygos vein, and the superior hemiazygos vein. They drain blood from the posterior parts of the intercostal spaces, the posterior abdominal wall, the pericardium, the diaphragm, the bronchi, and the esophagus. The origin of the azygos vein is variable. It is often formed by the union of the right as-cending lumbar vein and the right subcostal vein. The azygos vein ascends through the aor¬tic opening in the diaphragm on the right side of the aorta to the level of the fifth thoracic vertebra. Here the vein arches forward above the root of the right lung to empty into the pos¬terior surface of the superior vena cava. Note: The azygos vein leaves an impression on the right lung as the vein arches over the root. The azygos vein has numerous tributaries that in¬clude the eight lower intercostal veins, the right superior intercostal vein, the superior and inferior hemiazygos veins, and numerous mediastinal veins. The superior vena cava is one of the two main veins (the other being the inferior vena cava) bringing deoxygenated blood from the body to the heart. Veins from the head and upper body feed into the superior vena cava, which empties into the right atrium of the heart. Note: The inferior vena cava carries blood back to the right atrium from the lower part of the body. Remember: At the root of the neck, the internal jugular vein joins the subclavian vein to form the large brachiocephalic vein. This occurs on both sides of the neck, and the two brachiocephalic veins unite in the superior mediastinum to form the superior vena cava (the azygos vein also joins the posterior aspect of the superior vena cava just before it pierces the pericardium).

The inactive X chromosome in a female cell is called the:• Pineal body • Lateral body • Golgi Barr body

Barr body -- also known as the sex chromatin body In the female, the genetic activity of both X chromosomes is essential only during the first few weeks after conception. Later development requires just one functional X chromosome. The other X chromosome is inactivated and appears as a dense chromatin mass called the Barr body. This Barr body is attached to the nuclear membrane in the cells of a normal female. In the cells of a normal male, who has only one functional X chromosome, the Barr body is absent. Important: The Barr body's presence is the basis of sex determination tests (for example, amniocentesis). 1. The sex of an embryo can be determined at about the eighth week. Notes 2. Females have 45 active chromosomes and one inactive Barr body.

A young girl presents to the dentist with yellow, thin, chalky enamel, but sound dentin. The diagnosis is amelogenesis imperfecta and is a genetic disorder with malformed enamel. In amelogenesis imperfecta, there is an error in what stage in the life cycle of a tooth? • Initiation • Bud stage • Cap stage • Bell stage • Apposition • Calcification • Eruption • Attrition

Bell stage 1. Initiation (sixth to seventh weeks) -- Ectoderm lining stomodeum gives rise to oral ep¬ithelium and then to dental lamina, adjacent to deeper ectomesenchyme, which is influ¬enced by the neural crest cells. Induction is the main process involved. Congenital ab¬sence of teeth (anodontia) and supernumerary teeth result from an interruption in this phase. 2. Bud stage (eighth week) -- Growth of dental lamina into bud that penetrates growing ectomesenchyme. Proliferation is the main process involved. 3. Cap stage (ninth to tenth weeks) -- Enamel organ forms into a cap, surrounding the mass of the dental papilla from the ectomesenchyme and surrounded by the mass of the dental sac also from the ectomesenchyme, thus forming the tooth germ. Proliferation, differentiation, and morphogenesis are the main processes involved. Dens in dente, gemination, fusion, and tubercle formation occur during this phase. 4. Bell stage (eleventh to twelfth weeks) -- final shaping of tooth, cells differentiate into specific tissue forming cells (ameloblasts, odontoblasts, cementoblasts, and fibroblasts) in the enamel organ. Histodifferentiation and morphodifferentiation are the main processes involved. Macrodontia/microdontia occur during this stage. 5. Apposition (varies per tooth) -- cells that were differentiated into specific tissue-form¬ing cells begin to deposit the specific dental tissues (enamel, dentin, cementum, and pulp). Enamel dysplasia, concrescence, and the formation of enamel pearls occur during this stage. 6. Calcification (varies per tooth) -- mineralization 7. Eruption (varies per tooth) 8. Attrition (varies per tooth) Note: Dentinogenesis imperfecta and amelogenesis imperfecta occur during histo-differentiation (Bell stage).

Tendons, ligaments, cartilage, and bone are considered which type of human body tissue, which supports and binds other tissues? • Epithelium • Muscle tissue • Nerve tissue • Connective tissue

Connective tissue

Cementum is the closest in composition to which of the following? • Bone • Enamel • Dentin • Dental pulp

Bone Cementum is the bone-like mineralized tissue covering the anatomical roots of teeth. The primary function of cementum is to attach Sharpey's fibers. It has the following characteristics: • Slightly softer and lighter in color (yellow) than dentin • Formed by cementoblasts from the PDL, as opposed to dentin, which is formed from odontoblasts of the pulp. It develops from the dental sac • Most closely resembles bone (more so than dentin), except there are no haversian systems or blood vessels -- it is avascular • Mature cementum is by weight 65% mineralized or inorganic material (mainly calc¬ium hydroxyapatite), 23% organic material, and 12% water • The organic portion is primarily composed of collagen and protein • Has no nerve innervation. • Thickest at the tooth's apex and thinnest at the CEJ at the cervix of the tooth • Important in orthodontics. Cementum is more resistant to resorption than alveolar bone, permitting orthodontic movement of teeth without root resorption Two types of cementum (functionally there is no difference): 1. Acellular (sometimes called primary cementum) -- consists of the first layers of cementum deposited at the DCJ; acellular cementum is formed at a slow rate and cont¬ains no embedded cementocytes, usually predominate on the coronal two-thirds of the root. Thinnest at the CEJ. 2. Cellular (sometimes called secondary cementum) -- consists of the last layers of cementum deposited over the acellular cementum; cellular cementum is formed at a faster rate than acellular cementum and contains embedded cementoblasts. Cellular cementum occurs more frequently on the apical third of the root. Cellular cementum is usually the thickest to compensate for occlusallincisal wear and passive eruption of the tooth. Note: The composition of bone is roughly 50% inorganic, 25% collagen, and 25% water.

Origin Insertion Mandibular Movements Temporalis Masseter Medial pterygoid Lateral pterygoid (two heads)

Bony floor of temporal fossa Lower border and medial surface of the zygomatic arch The superficial head arises from the tuberosity of the maxilla. The deep head arises from the medial surface of the lateral pterygoid plate The upper head arises from the infratemporal surface of the greater wing of the sphenoid bone. The lower head arises from the lateral surface of the lateral pterygoid plate Coronoid process of mandible Lateral aspect of the ramus of the mandible Medial surface of the angle of the mandible Front of the neck of the man- dible and the articular disc of the TMJ The anterior and superior fibers elevate the mandible The posterior fibers retract the mandible Raises (elevates) the mandible to occlude the teeth in mastication Assists in raising (elevating) the mandible Lower heads: slight depression of the mandible (during jaw opening) One muscle: lateral deviation of the mandible (shift mandible to opposite side) Both muscles: protrusion of the mandible

The inguinal canal is an oblique passage through the lower part of the anterior abdominal wall and is present in: • Males only • Females only • Both sexes

Both sexes The inguinal canal allows structures of the spermatic cord to pass to and from the testis to the abdomen in the male. In the female, the smaller canal permits the passage of the round ligament of the uterus from the uterus to the labium majus. Note: In both sexes, the canal also transmits the ilioinguinal nerve. The spermatic cord is a collection of structures that traverse the inguinal canal and pass to and from the testis. The spermatic cord is covered with three concentric layers of fas¬cia derived from the layers of the anterior abdominal wall, and begins at the deep in¬guinal ring lateral to the inferior epigastric artery and ends at the testis. Structures of the spermatic cord: • Ductus (vas) deferens -- it is a cord-like structure; it conveys sperm from the epididymis to the ejaculatory duct, which is a passageway formed by the union of the deferent duct (vas deferens) and the excretory duct of the seminal vesicle. The ejaculatory duct opens into the prostatic urethra. • Testicular artery -- branch of the abdominal aorta; supplies mainly the testis and the epididymis. • Testicular veins -- an extensive venous plexus, the pampiniform plexus, leaves the posterior border of the testis. As the plexus ascends, it becomes reduced in size into a single testicular vein. This runs up on the posterior abdominal wall and drains into the left renal vein on the left side, and into the inferior vena cava on the right side. • Testicular lymph vessels -- ascend through the inguinal canal and pass up over the posterior abdominal wall to reach the lumbar lymph nodes on the side of the aorta at the level of the first lumbar vertebra. • Autonomic nerves -- sympathetic fibers run with the testicular artery from the renal or aortic sympathetic plexuses. Afferent sensory nerves accompany the efferent sym¬pathetic fibers.

Oral Mucosa types: region, General Clinical Appearance, General Microscopic appearance Lining mucosa Masticatory mucosa Specialized mucosa

Buccal mucosa, labial mucosa, alveolar mucosa, floor of the mouth, ventral tongue surface, and soft palate Free gingiva, attached gingiva, interdental gingiva, hard palate, and dorsal surface of tongue Dorsal tongue surface General Clinical Appearance Softer texture, moist surface, and ability to stretch and be compressed, acting as a cushion Rubbery surface texture and resiliency, serving as firm base Associated with lingual papillae General Microscopic appearance Thin nonkeratinized stratified squamous epithelium, few rete pegs, thin lamina propria Keratinized epithelium, many rete pegs, thick lamina propria Mostly keratinized. Note: The filiform and circumvallate papillae are keratinized, but the fungiform and foliate papillae are nonkeratinized

A 16-year-old girl who is just about to have her junior prom comes crying into the physician's office, but is lacrimating only from her right eye. The left half of her face is also paralyzed, and the physician diagnoses her with Bell's palsy. An oral exam reveals trauma to her buccal mucosa where her teeth have bitten her cheek. Which muscle, paralyzed in Bell's palsy, is responsible for keeping mucous membranes out of the plane of occlusion and food out of the buccal vestibule? • Medial pterygoid • Lateral pterygoid • Buccinator • Masseter • Temporalis

Buccinator The buccinator is one of the muscles of the cheeks and lips. On each side, the buccinator has a complex origin from: • The maxilla along the alveolar process superior to alveolar margin horizontally between the anterior border of the first and third molars • The mandible along the oblique line of the mandible between the first and third molars • The pterygomandibular ligament • The pterygomandibular raphe: a thin, fibrous band running from the hamulus of the medial pterygoid plate down to the mandible It inserts at orbicularis oris and skin at the angle of the mouth. It is traversed by the parotid duct. It is not a primary muscle of mastication -- it does not move the jaw -- and this is reflect¬ed in the buccinator's motor innervation from the facial nerve. However, proprioceptive fibers are derived from the buccal branch of the mandibular branch of the trigeminal nerve. The actions of the buccinator are to: 1. Move boluses of food out of the vestibule of the mouth and back towards the molar teeth. 2. Tense the cheeks during blowing and whistling. 3. Assist with closure of the mouth. 1. The facial and maxillary arteries supply blood to buccinator muscle. Notes 2. Food accumulating in the vestibule might suggest that the buccinator is not working properly. 3. If the point of a needle enters the parotid gland during an inferior alveolar injec¬tion and solution is deposited in the gland, the most likely result is paralysis of the buccinator muscle. 4. Damage to the facial nerve or its branches may cause weakness or paralysis of facial muscles called Bell's palsy.

No tunica media or adventitia is present in which type of blood vessel that exchanges substances via diffusion?

Capillaries

Exchange of gases in the tissue occurs in: • Arteries • Capillaries • Veins

Capillaries Unlike the arteries and veins, capillaries are very thin and fragile. The capillaries are actually only one epithelial cell thick. They are so thin that blood cells can only pass through them in single file. The exchange of oxygen and carbon dioxide takes place through the thin capillary wall. Arteries and veins run parallel throughout the body with a web-like network of capillaries, embedded in tissue, connecting them. The arteries pass their oxygen-rich blood to the capillaries, which allow the exchange of gases within the tissue. The capillaries then pass their waste-rich blood to the veins for transport back to the heart. Differences in blood pressure are reflected in vessel structure: • Arteries -- thick, muscular walls to accommodate the flow of blood at high speeds and pressures • Arterioles -- thinner walls that constrict or dilate as needed to control blood flow to the capillaries • Capillaries -- walls composed of only a single layer of endothelial cells • Venules -- receive blood from capillaries; walls thinner than those of arterioles • Veins -- thinner walls but larger diameters than arteries; maintain low blood pressure re-quired for return to heart

Capillaries

Capillaries are tiny blood vessels with extremely thin walls that consist of endothelium only; no tunica media or adventitia is present. They join arterioles and venules. These blood vessels accommodate erythrocytes one at a time. In certain structures (liver, spleen, bone marrow, and certain glands), the arterioles, rather than connecting with capillaries, empty into blood vessels called sinusoids. They have very, very thin walls that conform to the space in which they are located (form irregular tortuous tubes). Note: The velocity of blood flow is slowest in capillaries, and A decrease in vessel diameter causes an increase in resistance to blood flow.

Which of the following statements concerning cardiac muscle fibers are tru."-e EXCEPT one. Which one is the EXCEPTION? • Their characteristic feature is the presence of intercalated discs • Cardiac muscle fibers have less mitochondria between myofibrils and are poorer in myoglobin than most skeletal muscle fibers • Make up the thick, middle layer of the heart known as the myocardium • Have larger T tubules and less developed sarcoplasmic reticula compared to skeletal muscle fibers • In contrast to skeletal muscle fibers, cardiac muscle fibers are short, branched, and single or binucleated

Cardiac muscle fibers have less mitochondria between myofibrils and are poorer in myoglobin than most skeletal muscle fibers *** This is false; actually, cardiac muscle fibers have more mitochondria between myofibrils and are richer in myoglobin than most skeletal muscles. Like skeletal muscle fibers, cardiac muscle fibers contain myofilaments (contractile units) and are striated with actin and myosin. Cardiac muscle fibers contain large, oval centrally placed nuclei as well as strong, but thin, unions between fibers called intercalated discs. These intercalated discs provide low resistance for current flow. Important: Within the intercalated discs, desmosomes attach one cell to another while gap junctions allow electrical impulses to spread from cell to cell. Cardiac muscle fibers contract spontaneously without any nerve stimulus. They respond to increased demand by increasing the size of the fiber; this is known as compensatory hypertrophy. Note: Skeletal and cardiac muscle fibers cannot mitotically divide, but certain smooth muscle fibers can under hormonal influences (e.g., during pregnancy, the smooth muscle fibers of the myometrium of the uterus increase in length, and new cells are formed).

Carotid sinus syndrome

Carotid sinus syndrome is a temporary loss of consciousness that sometimes accompanies convulsive seizures because of the intensity of the carotid sinus reflex when pressure builds in one or both carotid sinuses.

After a large Thanksgiving dinner, the traditional American family notices: that they all are drowsy. The "food coma" is a result of oxygenated blood being restricted from the brain and being shunted to the stomach in order for digestion. All of the arteries that supply are derived directly or indirectly from the:

Celiac trunk (artery)

The nerve plexus of Raschkow is located in which zone of the dental pulp? • Cell-rich zone • Cell-free zone (zone of Weil) • Odontoblastic layer

Cell-free zone (zone of Weil) The pulp is the innermost tissue of the tooth. The pulp is formed from the central cells of the dental papilla. Anatomy of the pulp: • Coronal pulp -- located in the pulp chamber and forms pulp horns • Radicular pulp -- located in the pulp canals (root portion of tooth) • Apical foramen -- communicates with the PDL *** Accessory canals may also be associated with the pulp. Remember: These form when Hertwig's epithelial root sheath encounters a blood vessel during root formation. Root structure then forms around the vessel, forming the accessory canal. The central zone or pulp proper contains large nerves and blood vessels. This area is lined peripherally by a specialized odontogenic area that has the following zones (from the outermost zone closest to the dentin to the innermost zone of the pulp): • Odontoblastic layer: lines the outer pulpal wall and consists of the cell bodies of odontoblasts. Cell bodies of the afferent axons from the dentinal tubules are located between cell bodies of the odontoblasts. • Cell-free zone or zone of Weil: contains fewer cells than the odontoblastic layer. The capillary and nerve plexus (plexus of Raschkow) are located here • Cell-rich zone: contains an increased density of cells compared with the cell-free zone and also has a more extensive vascular system. Contains fibroblasts and odontoblast progenitor cells. • Pulpal core: located in the center of the pulp chamber; consists of many cells and an extensive vascular supply. Except for the location, the pulpal core is very similar to the cell-rich zone.

All of the following statements concerning the cervical plexus and its branches are true EXCEPT one. Which one is the EXCEPTION? • The motor nerves for most of the infrahyoid muscles are branches of the ansa cervicalis (loop formed by CI, C2, and C3) • Cervical nerves C5-C8 contribute motor fibers to the cervical plexus • It is positioned deep on the side of the neck, lateral to the first four cervical vertebrae • An important branch of each cervical plexus is the phrenic nerve that supplies the diaphragm • The supraclavicular nerves innervate the skin over the shoulder • The transverse cervical nerve provides sensory innervation to the anterior and lateral parts of the neck

Cervical nerves C5-C8 contribute motor fibers to the cervical plexus *** This is false; Cl - C4 contribute motor fibers to the cervical plexus. The four main pairs of nerve plexuses that are formed by the mixing and branching of the ventral rami of the spinal nerves: 1. Cervical plexus (C1-C4) -- provides cutaneous innervation to the skin of the neck, shoulder, and upper anterior chest wall as well as motor innervation to the infrahyoid (strap) muscles and geniohyoid muscle. The phrenic nerve (C3-05) is the motor nerve to the skeletal muscle of the diaphragm. 2. Brachial plexus (C5-C8 and T1) -- formed in the posterior triangle of the neck, the brachial plexus extends into the axilla, supplying nerves to the upper limb. It has three cords: • posterior -- axillary and radial nerves are main branches • lateral -- musculocutaneous nerve is main branch • medial -- ulnar nerve is main branch Note: The median nerve forms its two heads (medial and lateral) from the medial and lateral cords. 3. Lumbar plexus (Ll-L4) -- formed in the psoas muscle, the lumbar plexus supplies the lower abdomen and parts of the lower limb. Main branches are the femoral and obturator nerves. 4. Sacral plexus (L4-L5 and Sl-S4) -- lies in the posterior pelvic wall in front of the piriformis muscle. The sacral plexus supplies the lower back, pelvis, and parts of the thigh, leg, and foot. The main branch is the sciatic (largest nerve in the body).

Branches of the facial artery (cervical and facial portion) include:

Cervical portion: Tonsillar - to the tonsils. Ascending pharyngeal - to the pharyngeal wall. Glandular - to the submandibular gland. Submental - to the area below the chin Facial portion: Inferior labial - to the lower lip. Superior labial - to the upper lip and vestibule of nose. Lateral nasal - to the lateral wall of the nose (outer side). Angular - to the medial side of the eye. It is the terminal branch of the facial artery and can anastomose with the dorsal nasal branch of the ophthalmic artery

Characteristics of each: -Arteries: • Large (elastic arteries) • Small (muscular arteries) -Arterioles -Capillaries -Venules -Veins

Characteristics -Very thick tunica media that contains a lot of elastic fibers and some smooth muscle fibers Tunica media consists of almost entirely smooth muscle cells with few elastic fibers -Small vessels (diameter < .5 mm), small lumen, thicker tunica media with a lot of smooth muscle fibers -Small vessels (0.01 diameter), walls have endothelial layer only -Small vessels; walls have endothelium and very thin tunica adventitia; larger venules have thicker tunica adventitia -Thin tunica media with few smooth muscle fibers; thick tunica adventitia with little elastic tissue; larger lumen and thinner walls than the arteries they accompany; some contain valves and vasa vasorum (nutrient blood vessels that supply the walls of large veins)

Which of the following is not produced by the pancreas? • Lipase • Trypsinogen • Insulin • Cholecystokinin • Glucagon • Amylase

Cholecystokinin The pancreas is an elongated gland lying behind the stomach and in front of the aorta and inferior vena cava. The large head of the pancreas is framed by the C-shaped loop of the duodenum. Extending to the left from the head region are the neck, body, and tail of the pancreas, respectively. The tail meets the spleen on the left of the abdomen. Pancreatic secretions are collected by the main pancreatic duct (and accessory pancre-atic duct), which, together with the bile duct, enters the duodenum at the duodenal ampulla (ampulla of Vater). Most of the digestive process takes place in the duodenum, due to the action of pancreatic enzymes. The exocrine portion is formed by secretory cells arranged in small sacs called acini, which secrete digestive enzymes called pancreatic juices into the intestine. The endocrine portion consists of clusters of cells called pancreatic islets (islets of Langerhans), which are scattered among the acini. These cells produce insulin and glucagon, hormones that promote the cellular uptake of glucose and the breakdown of glycogen, respectively. 1. Endocrine portion (secretes into bloodstream) the following enzymes: pancreatic lipase, amylase, carboxypeptidase, elastase, and chymotrypsinogen. Islets of Langerhans (cell of pancreas): • Alpha cells: secrete glucagon, which counters the action of insulin • Beta cells: secrete insulin, which promotes uptake and storage of glucose 2. Exocrine portion (secretes through duct into duodenum): secretes the following enzymes: pancreatic lipase, amylase, carboxypeptidase, elastase, and chymotrypsinogen. • Acinar cells produce enzymes that digest proteins, carbohydrates, and fats. Tryp¬sinogen is then converted to trypsin in the small intestine Note: Cholecystokinin is produced by the duodenum and regulates pancreatic juice secretion.

The left atrium and left ventricle are supplied by the: • Anterior interventricular branch of the left coronary artery • Circumflex branch of the left coronary artery • Marginal branch of the right coronary artery • Posterior interventricular branch of the right coronary artery

Circumflex branch of the left coronarn arter The arterial blood supply of the heart is provided by the right and left coronary arteries, which arise from the aorta immediately above the aortic valve. They and their major branches are distributed over the surface of the heart lying within subepicardial connective tissue. The right coronary artery arises from the anterior aortic sinus of the ascending aorta and runs for¬ward between the pulmonary trunk and the right auricle. This artery gives rise to an important branch immediately after leaving the ascending aorta. This is the anterior right atrial branch, which gives rise to the important nodal artery. This artery supplies the SA node or pacemaker of the heart. The right coronary artery continues in the coronary sulcus, giving off a marginal branch, which supplies the right ventricle. Finally, the right coronary artery gives rise to the posterior in¬terventricular branch (posterior descending artery), which supplies both ventricles, and then anastomoses with the circumflex artery from the left coronary artery. The left coronary artery, which is usually larger than the right coronary artery, arises from the left posterior aortic sinus of the ascending aorta and passes forward between the pulmonary trunk and the left auricle. This artery divides into an anterior interventricular branch (left anterior de¬scending artery), which supplies the right and left ventricles and the interventricular septum, and a circumflex branch, which supplies the left atrium and the left ventricle. Important: The anterior interventricular artery is the one most often involved in coronary oc¬clusions and is often the one that is bypassed in bypass cardiac surgery. There are four sets of valves that keep the blood flowing in the proper direction through the cham¬bers of the heart: • Right and left atrioventricular valves (AV valves) -- are located between the atria and the ventricles. The valve on the right is called the tricuspid valve; on the left it is called the bicus¬pid (mitral) valve. These valves prevent backflow of blood into the atria during ventricular con¬traction. • Semilunar valves -- the pulmonary semilunar valve is located in the proximal end of the pul¬monary trunk. The aortic semilunar valve is located in the proximal end of the aorta. These valves prevent return of blood to the ventricles from the aorta and pulmonary trunk after con¬traction.

Structure, Location, Function, and Fate in the Newborn of the following: Umbilical vein Ductus venoms Foramen ovate Ductus arteriosum Umbilical arteries

Connects the placenta to the liver; forms a major portion of the umbilical cord Venous shunt within the liver to connect with the inferior vena cava Opening between the right and left atria Between the pulmonary trunk and the aortic arch Arise from internal iliac arteries; associated with the umbilical cord Transports nutrient-rich oxygenated blood from the placenta Transports oxygenated blood directly into the inferior vena cava A shunt to bypass the pulmonary circuitry A shunt to bypass the pulmonary circuitry Transport blood from the fetus to the placenta Forms the round ligament (also known as the ligamentum teres) of the liver Forms the ligamentum venosum, a fibrous cord in the liver Closes at birth and becomes the fossa ovalis, a depression in the interatrial septum Closes shortly after birth, atrophies, and becomes the ligamentum arteriosum Atrophy to become the lateral umbilical ligaments

The organic component of dentin primarily consists of: • Collagen fibers • Elastic fibers • Odontoblasts • Ameloblasts

Collagen fibers Dentin is the specialized connective tissue that makes up the bulk of the tooth, extending for almost its entire length. Dentin is hard, elastic, 70% inorganic, 20% organic, and 10% water. The inorganic component consists of mainly calcium hydroxyapatite with the chemical formula of Ca10(PO4)6(OH)2. This calcium hydroxyapatite is similar to that found in higher percentages in enamel and in lower percentages in bone and cementum. Smaller amounts of other minerals, such as carbonate and fluoride, are also present. 1. Unlike enamel, which is acellular, dentin has a cellular component that Notes is retained after its formation by odontoblasts. 2. Dentin and pulp tissue are both formed by the dental papilla. Pulp tissue is a loose, very vascular, and non-calcified connective tissue while dentin is avascular and a calcified tissue. 3. The main cell type in dentin is the odontoblast, which is derived from ectomesenchyme. 4. Dentin is much softer than enamel but harder than bone. Dentin is more flexible (lower modulus of elasticity) than enamel. Dentin's compressive strength is much higher than its tensile strength. 5. Dentin is more mineralized than cementum or bone but less mineralized than enamel. Morphologically and chemically, dentin has many characteristics in common with bone. 6. The major organic component of dentin is type I collagen fibers (91% to 92%).

Compact bone

Compact bone consists of closely packed osteons or haversian systems. The haversian system consists of a central canal called the haversian canal, which is surrounded by concentric rings (lamellae) of matrix. Between the rings of matrix, the bone cells (osteocytes) are located in spaces called lacunae. Small channels (canaliculi) radiate from the lacunae to the haversian canal to provide passageways through the hard matrix. In compact bone, the haversian systems are packed tightly together to form what appears to be a solid mass. The haversian canals contain blood vessels that are parallel to the long axis of the bone. These blood vessels interconnect, by way of perforating canals, with vessels on the surface of the bone.

In orthodontic tooth movement, bone remodeling is forced. The bands, wires, or appliances put pressure on one side of the tooth and adjacent alveolar bone, creating a zone of in the PDL. This leads to bone . On the opposite side of the tooth and bone, a zone develops in the PDL and causes the of bone. j • Tension; deposition; compression; resorption • Compression; resorption; tension; deposition • Compression; deposition; tension; resorption • Tension; resorption; compression; deposition

Compression; resorption; tension; deposition Orthodontic movement of teeth always causes remodeling of the alveolar bone proper to accommodate movement of the teeth. Important: The new alveolar bone deposited during orthodontic treatment is best described as intramembranous. Remember: • Osteoblasts (derived from mesenchyme, i.e., fibroblasts) are bone-forming cells that secrete the collagen and minerals needed to lay down new bone in their vicinity. • Osteoblasts that have been trapped in the osteoid produced by other surrounding osteoblasts are called osteocytes. Osteocytes maintain bones, play a role in controlling the extracellular concentration of calcium and phosphate, and are directly stimulated by calcitonin and inhibited by PTH (parathyroid hormone). • Osteoclasts (which are derived from stem cells in the bone marrow -- the same ones that produce monocytes and macrophages) are bone-resorbing cells. They are essential partners for bone modeling and remodeling. Their resorptive activity allows the permanent renewing of bone and regulates calcium homeostasis. 1. A similar situation is the alternate loosening and tightening of a deciduous Notes tooth before it is lost. This is caused by the alternate resorption (cementoclasts, osteoclasts) and apposition (cementoblasts, osteoblasts) of cementum and bone. 2. During active tooth eruption, there is apposition of bone on all surfaces of the alveolar crest and on all walls of the bony socket. Remember: Permanent teeth move occlusally and buccally when erupting.

conducting bronchioles

Conducting bronchioles are smaller extensions of bronchi (little bronchi). Those devoid of alveoli in their walls are nearer the hilum of the lung. These conducting passageways deliver air to passageways that have alveoli. The last generations of conducting bronchioles are called terminal bronchioles.

At the temporomandibular joint (TMJ), hinge movements occur between the:)

Condyle and articular disc. The TMJ is a synovial joint with two articular cavities. Each cavity is responsible for a different movement at the joint. An articular disc sits between the condylar process of the mandible on its inferior side and the mandibular fossa and articular eminence of the temporal bone on the superior side. This disc divides the joint into the two articular cavities, with one cavity acting as a hinge component and the other cavity serving as a gliding component. The lower part of the joint, between the condyle and the articular disc, is the hinge component of the joint. When the joint moves, this hinge component of the joint moves first, to initiate mandibular opening. The upper part of the joint, between the articular disc and the mandibular fossa and articular eminence of the temporal bone, creates the gliding component. During joint movement, this gliding cavity moves after the hinge component to terminate mandibular opening.

Pharyngeal Pouchs: from where are these structures derived? First Second Third and fourth

Contributes to the formation of the tympanic membrane (with first branchial groove), auditory tube, tympanic cavity, mastoid antrum Palatine tonsils Parathyroid and thymus glands

A fighter pilot in WWII gets shot down during a mission. Miraculously, he survives but arrives at the hospital unable to perform fine motor movements such as writing his name or buttoning his shirt. Which descending tract of the spinal cord would be damaged in this case? • Corticospinal tract • Rubrospinal tract • Vestibulospinal tract • Reticulospinal tract

Corticospinal tract Tracts descending to the spinal cord are concerned with voluntary motor function, muscle tone, reflexes and equilibrium, visceral innervation, and modulation of ascending sensory signals. Universally regarded as the single most important tract concerned with skilled voluntary activity, the corticospinal tract orig-inates from pyramid-shaped cells in the premotor, primary motor, and primary sensory cortex.

Site of exit from skull, component and function for the following: Olfactory (CN I) Optic (CN II) Oculomotor (CN III) Trochlear (CN IV)

Cribriform plate of ethmoid bone Optic foramen Superior orbital fissure Superior orbital fissure Special sensory (special afferent) Special sensory (special afferent) Somatic motor (general somatic efferent) Visceral motor (general visceral efferent) Somatic motor (general somatic efferent) Sense of smell Conveys visual information from the retina Supplies four of the six extraocular muscles of the eye and the levator palpebrae superioris muscle of the upper eyelid Parasympathetic innervation of the constrictor pupillae and ciliary muscles Innervates the superior oblique muscle

Cribriform plate and Perpendicular plate

Cribriform plate: Contains many olfactory foramina. The olfactory nerves pass through these foramina. Note: Damage to this area typically results in the loss of sense of smell. Perpendicular plate: The crista galli is a midline projection from the perpendicular plate that serves as an attachment for the falx cerebri.

A surgeon performing a thyroidectomy accidentally transects a nerve. The patient then presents with hoarseness and difficulty breathing. There is a loss of sensation below the vocal folds and loss of motor innervation to all of the intrinsic muscles of the larynx EXCEPT the: • Thyroarytenoid • Posterior cricoarytenoid • Transverse cricoarytenoid • Cricothyroid • Lateral cricoarytenoid

Cricothyroid *** The nerve that was transected was the recurrent laryngeal nerve. Note: Damage to this nerve (as a result of surgery or disease) can result in hoarse- ness and difficulty breathing. Intrinsic muscles of the larynx: • Cricothyroid: stretches the vocal chords • Posterior cricoarytenoid: maintains wide airways (for breathing) • Thyroarytenoid: closes the vestibule • Aryepiglottic: closes the vestibule • Transverse cricoarytenoid: contracts to close the airway posteriorly for speech • Lateral cricoarytenoid: adducts the vocal cords • Thyroepiglotticus: helps close vestibule • Vocalis: shortens vocal cords, is the antagonist of the cricothyroid muscle The vagus nerve provides sensory and motor innervation to the larynx: 1. The recurrent laryngeal nerve supplies all the intrinsic muscles except the cricothyroid. 2. The cricothyroid muscle is supplied by the external branch of the superior laryn¬geal nerve. 3. Sensation above the vocal folds is supplied by the internal branch of the superior laryngeal nerve. 4. Sensation below the vocal folds is supplied by the recurrent laryngeal nerve.

All of the laryngeal muscles are innervated by the recurrent laryngeal nerve\ EXCEPT one. Which one is the EXCEPTION? • Posterior cricoarytenoid • Thyroarytenoid • Cricothyroid • Transverse arytenoid • Lateral cricoarytenoid

Cricothyroid muscle The vagus nerve possesses two sensory ganglia: 1. Superior ganglion -- lies on nerve within the jugular foramen 2. Inferior ganglion -- lies on nerve just below the jugular foramen Branches that arise from the superior ganglion: • Meningeal -- supplies dura mater • Auricular -- supplies auricle, external auditory meatus Branches that arise from the inferior ganglion: • Pharyngeal -- forms pharyngeal plexus, supplies all of the muscles of the pharynx, except the stylopharyngeus muscle (innervated by glossopharyngeal nerve) and all of the muscles of the soft palate, except the tensor veli palatini (innervated by mandibular nerve, V-3). *** It joins branches from the glossopharyngeal nerve and the sympathetic trunk, to form the pharyngeal plexus. • Superior laryngeal -- divides into: — Internal laryngeal -- travels with superior laryngeal artery and pierces the thyro- hyoid membrane. Supplies mucous membranes of the larynx above the vocal folds. — External laryngeal -- travels with superior thyroid artery and supplies the crico-thyroid muscle. The right recurrent laryngeal nerve arises from the vagus, as the nerve crosses the first part of the subclavian artery. The nerve supplies all of the muscles of the larynx except the cricothy¬roid, which is supplied by the external laryngeal branch of the superior laryngeal nerve. The nerve also supplies the mucous membrane of the larynx below the vocal folds, and the mu¬cous membrane of the upper part of the trachea. The left recurrent laryngeal nerve arises from the vagus as the nerve crosses the arch of the aorta in the thorax. The nerve supplies the same muscles and mucous membranes as the right recurrent laryngeal nerve, except on the left side.

EGenerally, as the dental pulp ages, the number of cells number of collagen fibers , and the • Decreases; decreases • Decreases; increases • Increases; decreases • Increases; increases

Decreases; increases Important: As the dental pulp ages, the following changes take place: • Decreased: - intercellular substance, water, and cells *** Major decrease in the number of undifferentiated mesenchymal cells - size of the pulp cavity due to the addition of secondary or tertiary dentin • Increased: - number of collagen fibers - calcifications within the pulp (called denticles or pulp stones) Important point: As the pulp ages, it becomes more fibrotic, leading to a reduction in the regenerative capacity of the pulp. Remember: 1. The only type of nerve ending found in the pulp is the free nerve ending, which is a specific receptor for pain. These pain receptors are located in the plexus of Raschkow. Regardless of the source of stimulation (heat, cold, pressure), the only response will be pain. 2. The pulp contains both myelinated (mostly) and unmyelinated nerve fibers. They are afferent and sympathetic. 3. The myelinated fibers are the axons of sensory or afferent neurons that are located in the dentinal tubules in dentin. 4. The unmyelinated fibers are sympathetic and associated with the blood vessels. Note: Proprioceptors (which respond to stimuli regarding movement) are not found in the pulp.

Which type of connective tissue, seen in ligaments and tendons, is composed of closely packed collagenous fibers arranged in a consistent pattern? • Loose connective tissue • Dense irregular connective tissue • Dense regular connective tissue • Elastic connective tissue

Dense regular connective tissue Connective tissue derives from mesenchyme (mesoderm). Compared with epithelium, connective tissue is usually composed of fewer cells spaced further apart and containing larger amounts of matrix between the cells (except in adipose connective tissue). The most common cell is the fibroblast. Other cells found in connective tissue include migrated white blood cells such as macrophages, basophils (mast cells), lymphocytes (including plasma cells), and neutrophils (PMNs). Connective tissue includes bone, cartilage, and adipose (fatty) tissue. Connective tissue serves a "connecting" function. It supports and binds other tissues. Unlike epithelial tissue, connective tissue typically has cells scattered throughout an extracellular matrix. One method of classifying connective tissue is according to texture, which is either: • Soft: includes those tissues found in the deeper layers of the skin and oral mucosa • Firm: consists of different types of cartilage • Rigid: consists of bone • Fluid: consists of blood with all its components and lymph Soft connective tissue can be classified as: • Loose (areolar): consists predominantly of cells or matrix in an irregular or loose arrange¬ment. Serves as padding for the deeper portions of the body • Dense: which provides structural support, has greater fiber (protein) concentration, and is tightly packed. Dense is further subdivided into: • Dense regular connective tissue: has a regular arrangement of tightly packed, strong, parallel collagen fibers with few fibroblast cells. This tissue includes tendons, ligaments, and aponeuroses. • Dense irregular connective tissue: has tightly packed, strong, parallel collagen fibers arranged in an inconsistent or irregular pattern. This tissue is found in the dermis, submucosa of the GI tract, organ capsules, and deep fascia.

The tooth germ is composed of all of the following EXCEPT one. Which one is the EXCEPTION? • Enamel organ • Dental sac • Dental pulp • Dental papilla

Dental pulp Components of the tooth germ: 1. Enamel organ, which is formed from oral epithelium, which is derived from ectoderm. The enamel organ has four distinct cell layers: 1. Outer enamel epithelium 2. Inner enamel epithelium 3. Stratum intermedium 4. Stellate reticulum *** The enamel organ will give rise to enamel and will eventually form Hertwig's epithelial root sheath (HERS). 2. Dental sac, which is formed from mesenchyme (ectomesenchyme), which is derived from neural crest cells. The dental sac surrounds the developing tooth germ and will give rise to the cementum, the PDL, and the alveolar bone proper. 3. Dental papilla, which is also formed from mesenchyme (ectomesenchyme), which is derived from neural crest cells. The dental papilla will give rise to the dentin and dental pulp. Note: The outer layers of cells differentiate into the odontoblasts (dentin formingcells).

All of the following arise from the dental sac EXCEPT one. Which one is the exception: • Alveolar bone proper • Cement= • Periodontal ligament • Dental pulp

Dental pulp Peripheral cells of the dental papilla differentiate into odontoblasts that produce predentin that calcifies and becomes dentin. The center of the dental papilla will become the dental pulp. Cementoblasts differentiate from the inner layer of mesenchyme of the dental sac, adjacent to the tooth root. Cementoblasts are cells that form cementum. The dental sac will also form the periodontal ligament and the alveolar bone proper. Cells from the inner enamel epithelium of the enamel organ differentiate into ameloblasts that produce enamel. The inner and outer enamel epithelia of the enamel organ come together in the neck region and form Hertwig's epithelial root sheath.

Similar to the alveolar bone, the PDL is derived from the: • Dental papilla • Dental sac • Stratum reticulum • Stellate reticulum

Dental sac The periodontal ligament is that part of the periodontium that provides for the attachment of the teeth to the surrounding alveolar bone by way of the cementum. The PDL appears as the periodontal space of 0.4 to 1 5 mm on radiographs, a radiolucent area between the radiopaque lamina dura of the alveolar bone proper and the radiopaque cementum. The PDL is an organized fibrous connective tissue that also maintains the gingiva in proper relationship to the teeth. In addition, the PDL transmits occlusal forces from the teeth to the bone, allowing for a small amount of movement and acting as a shock ab-sorber for the soft tissue structures around the teeth, such as the nerves and blood vessels. 1. The PDL becomes very thin and loses the regular arrangement of its fiber when a tooth loses its function (hypofunction). This also occurs in areas of tension as opposed to areas of compression. Teeth in hyperfunction have an increased PDL width. 2. Unlike other connective tissues of the periodontium, the PDL does not show the changes related to aging, although the PDL can undergo drastic changes as a result of periodontal disease. 3. Remnants of Hertwig's epithelial root sheath found in the PDL of a functional tooth are called epithelial rests of Malassez. These groups of epithelial cells may become located in the mature periodontal ligament (called cementicles).

Tooth sensitivity to cold, hot, or pressure stimuli is usually caused by exposure of which oral tissues? • Dentin • Cementum • Pulp • Enamel

Dentin

L Where would you expect to see the incremental lines of von Ebner? ) • Alveolar bone • Enamel • Dentin • Cementum

Dentin The incremental (or imbrication) lines of von Ebner in dentin can be likened to the growth rings or incremental lines of Retzius in enamel. The incremental lines of von Ebner show the incremental nature of dentin apposition and run at right angle to the dentinal tubules. The contour lines of Owen are a number of adjoining parallel imbrication lines that are present in stained dentin. These contour lines demonstrate a disturbance in body metab¬olism that affects the odontoblasts by altering their formation efforts. These contour lines appear together as a series of dark bands. The most pronounced contour line is the neonatal line that occurs during the trauma of birth. Other contour lines occur with tetracycline staining of the teeth, in which the an¬tibiotic becomes permanently and chemically bound to the dentin. Tomes' granular layer is most often found in the peripheral portion of the dentin be-neath the root's cementum adjacent to the DCJ (dentinocemental junction). This area only looks granular because of its spotty microscopic appearance. The cause of the change in this region of dentin is unknown.

Amelogenesis (the formation of enamel) begins at the: • Cementoenamel junction (CEJ) • Dentinoenamel junction (DEJ) • Cementodentinal junction (CDJ) • Mucogingival junction (MGJ)

Dentinoenamel junction (DEJ) Amelogenesis is the process of enamel matrix formation that occurs during the appositional stage of tooth development. Enamel matrix is produced by ameloblast cells. These cells are columnar cells that differentiate during the apposition stage in the crown area. The enamel matrix is secreted from each ameloblast from its Tomes' process. Tomes' process is the secretory surface of the ameloblast that faces the dentinoenamel junction (DEJ). Enamel matrix is first formed in the incisal/occlusal portion of the future crown near the forming DEJ. Important: The DEJ is the interface between the dentin and enamel. The DEJ is the remnant of the onset of enamel formation. During amelogenesis, ameloblasts enter their first formative state after the first layer of dentin is formed. They secrete enamel matrix as they retreat away from the DEJ. This matrix then mineralizes. Remember: Enamel is produced in a rhythmic fashion. Important: The odontoblasts begin dentin formation (dentinogenesis) immediately before enamel formation by the ameloblasts. Dentinogenesis begins with the odontoblasts laying down a dentin matrix or predentin, moving from the DEJ inward toward the pulp. The most recently formed layer of dentin is always adjacent to the pulpal surface. Note: Predentin or dentin matrix is a mesenchymal product consisting of nonmineralized collagen fibers. These odontoblasts are induced by the newly formed ameloblasts to produce predentin in lay¬ers, moving away from the DEJ. 1. The DEJ is also the area at which calcification of a tooth begins. 2. The morphology of the DEJ is determined at the bell stage. 3. The oldest enamel in a fully erupted molar is located at the DEJ underlying a cusp. 4. Research has shown that in order for ameloblasts to form enamel, cells from the stratum intermedium must be present.

Which fiber subgroup of the gingival fiber group (gingival ligament) inserts in the cementum on the root, apical to the epithelial attachment, and extends into the lamina propria of the marginal gingiva? • Circular ligament • Dentogingival ligament • Alveologingival ligament • Dentoperiosteal ligament

Dentogingival ligafnent Gingival fibers are collagen fibers that support only the marginal gingival tissues to maintain their relationship to the tooth. The gingival fiber group (also called the gingival ligament) is the name given to separate but adjacent fiber groups that are found within the lamina propria of the marginal gingiva. Note: Some histologists consider the gingival ligament to be part of the principal fibers (also called the alveologingival ligament) of the PDL. Gingival ligament (or gingival fiber group): • Circular ligament -- this fiber subgroup of the gingival fiber group is located in the lamina propria of the marginal gingiva. The circular ligament encircles the tooth and helps maintain gingival integrity. • Dentogingival ligament -- this fiber subgroup of the gingival fiber group inserts in the cementum on the root, apical to the epithelial attachment, and extends into the lamina propria of the marginal gingiva. Thus, this ligament has only one mineralized attachment to the cementum. The dentogingival ligament works with the circular ligament to maintain gingival integrity. • Alveologingival ligament -- this fiber subgroup of the gingival fiber group extends from the alveolar crest of the alveolar bone proper and radiates coronally into the overlying lamina propria of the marginal gingiva. These fibers may possibly help to attach the gingiva to the alveolar bone because of their one mineralized attachment to bone. • Dentoperiosteal ligament -- this fiber subgroup of the gingival fiber group courses from the cementum, near the cementoenamel junction, across the alveolar crest. These fibers possibly anchor the tooth to the bone and protect the deeper periodontal liga¬ment.

A 56-year-old male patient with type II diabetes comes into the emergency room with a painful blistering skin rash localized over the left side of his forehead. The unilateral nature indicates a herpes zoster (shingles) infection. A localized area of skin that has its sensation via a single nerve from a single nerve root of the spinal cord, and which is isolated in shingles, is called a: • Fasciculus • Dermatome • Spindle • Bundle

Dermatome Dermatomes are the areas of skin supplied by a single spinal nerve; however, there is usually some overlap between adjacent dermatomes. Each of the 31 segments of the spinal cord gives rise to a pair of spinal nerves, which carry messages into and out of the CNS. These spinal nerves branch into and service particular areas of the body. Ultimately, each nerve ends up innervating a different region of the skin, called a dermatome, with the exception of spinal nerve C1, which does not play a role in dermatomes. Peripheral nerve innervation of the skin (cutaneous innervation) usually forms a different pattern from spinal nerve skin innervation (dermatome) because the ventral primary divisions of spinal nerves form plexuses. This allows multiple spinal nerves to constitute a peripheral nerve. For example, the musculocutaneous nerve is composed of ventral primary divisions of spinal nerves C5, C6, and C7. When the cutaneous portion of the nerve reaches the skin of the lateral foramen, the branches from each of the spinal nerves supply their respective dermatomes. Key point to remember: The pattern of distribution of the peripheral nerve (musculocutaneous) is different from the dermatome pattern. Important: Cranial nerve dermatomes do not have any overlap (are not innervated by more than one nerve) whereas spinal nerve dermatomes overlap each other by 50% as insurance against anesthesia of a dermatome. The loss of the overlap requires the loss of innervation to three adjacent dermatomes to produce anesthesia in the middle dermatome. For example, all three of the dorsal roots or intercostal nerves of T4, T5, and T6 would have to be severed or damaged to create anesthesia in dermatome T5. Severing a peripheral nerve produces a different pattern of anesthesia on the skin. Note: This is diagnosed by the neurologist to determine if the lesion is in a spinal nerve or a peripheral nerve. Remember: Referred pain is caused when the sensory fibers from an internal organ enter the spinal cord in the same root as fibers from a dermatome. The brain is poor at interpreting visceral pain and instead interprets it as pain from the somatic area of the dermatome. So pain in the heart is often interpreted as pain in the left arm or shoulder, pain in the diaphragm is interpreted as along the left clavicle and neck, and the "stitch in your side" you sometimes feel when running is pain in the liver as its vessels vasoconstrict.

Which structure divides the anterior (ventral) body cavity into an upper thoracic cavity and a lower abdominopelvic cavity? • Liver • Diaphragm • Stomach • Lungs

Diaphragm Body cavities are spaces within the body that contain the internal organs. The dorsal (poste¬rior) and ventral (anterior) cavities are the two major closed cavities. • Dorsal cavity is subdivided into two cavities: 1. Cranial cavity (skull) -- encases the brain 2. Vertebral cavity (also called the spinal or vertebral canal) -- is formed by portions of the bones (vertebrae) that form the spine. It encloses the spinal cord. *** These two cavities communicate through the foramen magnum. These cavities are lined by meninges. The fluid in these cavities is called cerebrospinal fluid. • Ventral cavity: is subdivided into two cavities 1. The thoracic cavity, is surrounded by the ribs and chest muscles. The thoracic cavity is subdivided into: • Pleural cavities (right and left) -- each of which contains a lung and the mediast-inum, which contains the heart, large vessels of the heart, trachea, esophagus, thymus, lymph nodes, and other blood vessels and nerves. Remember: The mediastinum is further divided into four areas: the middle, the ant-erior, posterior, and superior areas. • Pericardial cavity -- between the visceral and parietal layers of the serous peri-cardium, contains a thin film of fluid 2. Abdominopelvic cavity, which has two regions: • Abdominal cavity -- contains the stomach, intestines, spleen, liver, and other int-ernal organs • Pelvic cavity -- inferior to the abdominal cavity, contains bladder, some reproduct¬ive structures (see *** below), and the rectum. *** In the male -- the paired ductus deferens and seminal vesicle and the unpaired prostate. In the female -- the paired ovaries and the unpaired uterus. *** The two cavities (thoracic and abdominopelvic) communicate through an opening in the diaphragm called the hiatus.

Which of the following meningeal structures is a ring-shaped fold that allows the passage of the infundibulum of the pituitary gland? • Tentorium cerebelli • Falx cerebri • Falx cerebelli • Diaphragma sellae

Diaphragma sellae The dura mater is the outermost tough fibrous layer that lines the skull and forms folds, or reflections, that descend into the brain's fissures and provide stability. The dura mater is composed of two layers. The endosteal layer adheres tightly to the inner surface of the cranium, and the meningeal layer forms partitions (folds or reflections) that descend into the brain's fissures and provide stability. The dural folds are the following: Two vertical folds: • Falx cerebri -- lies in the longitudinal fissure and separates the cerebral hemispheres. Contains inferior and superior sagittal sinuses. • Falx cerebelli -- separates the two lobes of the cerebellum. Contains occipital sinus. A horizontal fold: • Tentorium cerebelli -- separates the cerebrum and the cerebellum. Contains the straight, transverse, and superior petrosal sinuses. The dural venous sinuses are spaces between the endosteal and meningeal layers of the dura. The sinuses contain venous blood that originates for the most part from the brain or cranial cavity. The sinuses contain an endothelial lining that is continuous into the veins that are connected to the sinuses. There are no valves in the sinuses or in the veins that are connected to the sinuses. The vast majority of the venous blood in the sinus drains from the cranium via the internal jugular vein. Note: The diaphragma sellae is a ring-shaped fold of dura mater covering the sella tur¬cica, and containing an aperture for passage of the infundibulum of the pituitary gland.

The hypothalamus is part of the: • Basal nuclei • Diencephalon • Cerebrum • Cerebellum

Diencephalon The brain lies within the cranial cavity of the skull and is made up of billions of nerve cells (neurons) and supporting cells (glia). Neuronal cell bodies group together as gray mat¬ter, and their processes group together as white matter. The brain can be divided into four main parts: the cerebrum, diencephalon, brain stem, and cerebellum. • The cerebrum is the largest part of the brain and consists of the five paired lobes with the two cerebral hemispheres, connected by a mass of white matter called the corpus callosum. The cerebrum accounts for about 80% of the brain's mass and is concerned with higher functions, including perception of sensory impulses, instigation of voluntary movement, memory, thought, and reasoning. There are two layers of the cerebrum: - The cerebral cortex is the thin, wrinkled gray matter covering each hemisphere - The cerebral medulla is a thicker core of white matter • The diencephalon lies beneath the cerebral hemispheres and has two main structures -- the thalamus and the hypothalamus. The walnut-sized thalamus is a large mass of gray matter that lies on either side of the third ventricle. The thalamus is a great relay station on the afferent sensory pathway to the cerebral cortex. The tiny hypothalamus forms the lower part of the lateral wall and floor of the third ventricle. The hypothala¬mus exerts an influence on a wide range of body functions. Remember -- Each portion of the brain consists basically of three areas: 1. Gray matter -- composed primarily of unmyelinated nerve cell bodies 2. White matter -- composed basically of myelinated nerve fibers 3. Ventricles -- spaces filled with cerebrospinal fluid • The cerebellum is attached to the brain and features a highly folded surface. It is im¬portant in the control of movement and balance.

Which of the following spinal nerve structures is exclusively composed of sensory fibers? • Ventral root • Dorsal root • Ventral rami • Dorsal rami

Dorsal root The spinal cord is the connection center for the reflexes as well as the afferent (sensory) and efferent (motor) pathways for most of the body below the head and neck. The spinal cord begins at the brainstem and ends at about the second lumbar vertebra. The sensory, motor, and interneurons are found in specific parts of the spinal cord and nearby structures. Sensory neurons have their cell bodies in the spinal (dor¬sal root) ganglion. Their axons travel through the dorsal root into the gray matter of the cord. Within the gray matter are interneurons with which the sensory neurons may connect. Also located in the gray mat¬ter are the motor neurons whose axons travel out of the cord through the ventral root. The white mat¬ter surrounds the gray matter. It contains the spinal tracts that ascend and descend the spinal cord. At 31 places along the spinal cord, the dorsal and ventral roots come together to form spinal nerves. Spinal nerves contain both sensory and motor fibers, as do most nerves. Spinal nerves are given num-bers that indicate the portion of the vertebral column in which the nerves arise. There are 8 cervical (C1-C8), 12 thoracics (T1-T12), 5 lumbar (L 1 -L5), 5 sacral (S1-S5), and 1 coccygeal nerve. Nerve C1 arises between the cranium and atlas (1st cervical vertebra), and C8 arises between the 7th cervical and 1st thoracic vertebra. All the others arise below the respective vertebra or former vertebra in the case of the sacrum. Spinal nerves divide into branches called rami. Ventral primary rami exit anteriorly, and dorsal primary rami, posteriorly. A nerve plexus is a network of adjacent spinal nerves that join together. The name of each plexus de-scribes the area its nerves supply. The major nerve plexuses and areas they supply are: • cervical: head, neck, shoulders, diaphragm • brachial: upper limbs and some neck and shoulder muscles • lumbar: part of the abdominal wall, lower limbs, and external male genitalia • sacral: perineum, buttocks, and most of the lower limbs • pudendal: external female genitalia Sensory impulses travel along the sensory (afferent, or ascending) neural pathways to the sensory cor-tex in the parietal lobe of the brain where they are interpreted. Motor impulses travel from the brain to the muscles along the motor (efferent, or descending) pathways. These impulses originate in the motor cortex of the frontal lobe and travel along upper motor neurons to the peripheral nervous system. Upper motor neurons originate in the brain and from two major systems, the pyramidal and extrapyramidal systems.

A patient comes into the orthodontist's office as referred to by his general dentist. The orthodontist notes the patient's tongue thrusts and notes that early treatment could prevent skeletal problems. Soft tissue development is thought to encourage mandibular growth:

Downward and forward. The space between the jaws into which the teeth erupt is generally considered to be provided by growth at the mandibular condyles (especially the molars). The condyle is a major site of growth. Many arguments have been made about condyle function in mandibular growth. Most authorities agree that soft-tissue development carries the mandible forward and downward, while condylar growth fills in the resultant space to maintain contact with the base of the skull.

Which meningeal layer is fibrous and forms the falx cerebri and falx cerebelli? • Dura mater • Araclmoid mater (membrane) • Pia mater

Dura mater The meninges are three concentric protective membranes surrounding the brain and spinal cord (the CNS). 1. Dura mater -- the outermost tough fibrous layer that lines the skull and forms folds, or reflections, that descend into the brain's fissures and provide stability. The dural folds are the following: • Falx cerebri - lies in the longitudinal fissure and separates the cerebral hemispheres • Tentorium cerebelli - separates the cerebrum and the cerebellum • Falx cerebelli - separates the two lobes of the cerebellum 2. Arachnoid membrane -- is a fragile network of collagen and elastin fibers with a cobweb-like appearance. The arachnoid membrane has moderate vascularity and lies between the dura mater and the pia mater. 3. Pia mater -- innermost membrane, it is an extremely thin membrane made up of col-lagen and elastic fibers containing many blood vessels. The pia mater adheres closely to the brain and spinal cord. *** These are the structures involved in meningitis, an inflammation of the meninges, which, if severe, may become encephalitis, an inflammation of the brain. The subarachnoid space, filled with cerebrospinal fluid, separates the arachnoid mem¬brane and the pia mater. In addition, the meningeal area has two potential spaces: • Epidural space - over the dura mater; becomes a real space in the presence of pathol-ogy, such as accumulation of blood from a torn meningeal artery (an epidural hematoma) • Subdural space - a closed space with no egress between the dura mater and the arach-noid membrane; often the site of hemorrhage after head trauma Note: In the ventricles of the brain, the pia mater and ependymal cells contribute to the formation of the choroid plexuses. It is these plexuses that regulate the intraventricular pressure by secretion and absorption of cerebrospinal fluid.

The veins of the brain are direct tributaries of the: • Internal jugular vein • Dural sinuses • Diploic veins • Emissary veins • Pterygoid venous plexus

Dural sinuses (also called cerebral sinuses or sinuses of dura mater) The dural sinuses are large, endothelium-lined venous channels situated between the two layers of dura mater, the endosteal and the meningeal layers. The dural sinuses are devoid of valves and are part of the venous system of the dura mater. Major cranial sinuses in¬clude a postero-superior group, at the upper and back part of the skull (such as superior sagittal, inferior sagittal, straight, transverse, and occipital) and an antero-inferior group, at the base of the skull (such as cavernous, petrosal, and basilar plexus). Important: The veins of the brain are direct tributaries of the dural venous sinuses. 1. The emissary veins, which are valveless, connect the dural venous sinuses with the veins of the scalp. 2. An emissary vein, found in the foramen ovale, is a means of communication between the pterygoid plexus and the cavernous sinus. 3. The diploic veins lie in channels in the diploe of the skull and communicate with the dural sinuses, the veins of the scalp, and the meningeal veins. 4. The internal jugular vein begins in the jugular foramen as a continuation of the sigmoid sinus. This vein descends in the carotid sheath and ends in the brachiocephalic vein. It receives blood from the brain, face, and the neck. 5. Generally, the veins of the head and neck do not have valves.

Cooper's ligaments -- fibrous bands attached to the musculature -- support: • Each testis • Each ovary • Each body of the epididymis • Each breast

Each breast The mammary glands (breasts) are located on either side of the anterior chest wall over the greater pectoral and the anterior serratus muscles. These glands are specialized accessory glands that secrete milk. They are formed from many small tubules grouped into a lobule. Several lobules constitute a lobe, each of which has an interlobular duct. Many of these ducts combine to form a lactiferous duct, which terminates at the nipple. The nipple is present on each breast and presents as a centrally located pigmented area of erectile tissue ringed by an areola that's darker than the adjacent tissue. The arterial supply of the breast is from perforating branches of the internal thoracic artery and the intercostal arteries. The axillary artery also supplies the gland via its lat¬eral thoracic and thoracoacromial branches. Several chains of lymph nodes drain different areas of the breast and axilla. The node chains and the areas they drain are as follows: • pectoral- most of the breast and anterior chest • brachial- most of the arm • subscapular- posterior chest wall and part of the arm • midaxillary- pectoral, brachial, and subscapular nodes • internal mammary nodes- mammary lobes 1. Breast cancer causes dimpling of the overlying skin and nipple retraction. 2. The suspensory ligaments (Cooper's ligaments) are strong, fibrous process¬es that run from the derrnis of the skin to the deep layer of superficial fascia through the breast. 3. Important: Mammary, sweat, lacrimal, and salivary glands contain a special type of smooth muscle cell called myoepithelial cells (star-shaped). These cells have processes that spiral around some of the secretory cells of these glands. The contraction of these processes forces the secretion of the glands toward the ducts.

lung shape

Each lung is shaped like a cone. It has a blunt apex, a concave base (that sits on the diaphragm), a convex costal surface, and a concave mediastinal surface. At the middle of the mediastinal surface, the hilum is located, which is a depression in which the bronchi, vessels, and nerves that form the root enter and leave the lung.

Which of the following embryonic tissue types gives rise to the central nervous system? • Ectoderm • Endoderm • Mesoderm

Ectoderm During the latter part of the third week of prenatal development, the central nervous sys¬tem begins to develop in the embryo. Many steps occur during this week to form the be¬ginning of the spinal cord and brain. First, a specialized group of cells differentiates from the ectoderm. These cells are the neuroectoderm, and they are localized to the neural plate of the embryo. The neural plate is a band of cells that extends the length of the embryo, from the cephalic end to the caudal end. This plate undergoes further growth and thickening, which cause the plate to deepen and invaginate centrally, forming the neural groove. Near the end of the third week, the neural groove deepens further and is surrounded by the neural folds. As further growth of the neuroectoderm occurs, the neural folds meet superior to the neural groove, and a neural tube is formed during the fourth week. The neural tube undergoes fusion at its most superior portion and forms the future spinal cord as well as other neural tissues. Important: During the third week, another specialized group of cells, the neural crest cells, develop from the neuroectoderm. These cells migrate from the crests of the neural folds and disperse within the mesenchyme. These migrated cells are involved in the development of many face and neck structures, such as the branchial arches. Note: These neural crest cells are essential in the development of the face, neck, and oral tissues. Remember: The growth of neural tissue during the fourth week of prenatal develop-ment causes folding of the embryonic disc into an embryo, establishing for the first time the human axis and placing tissues in their proper positions for further embyonic devel¬opment.

The primitive mouth, or stomodeum, initially appears as a shallow depression in the embryonic surface at the cephalic end before the fourth week of prenatal development. • Ectoderm • Endoderm • Mesoderm

Ectoderm The oral cavity (primitive mouth or stomodeum) appears as a shallow depression in the embryonic surface ectoderm. At this time (before the fourth week), this stomodeum is limited in depth by the oropharyngeal membrane ((buccophalyngeal membrane). This temporary membrane, consisting of external ectoderm overlying endoderm, was formed during the third week of prenatal development. The membrane also separates the stomodeum from the primitive pharynx. The primitive pharynx is the cranial portion of the foregut, the beginning of the future digestive tract. The first event in the development of the face, during the fourth week of prenatal devel¬opment, is disintegration of the oropharyngeal membrane. With this disintegration of the membrane, the stomodeum is increased in depth, enlarging it. In the future, the stomodeum will give rise to the oral cavity, which is lined by oral ep¬ithelium, derived from ectoderm as a result of embryonic folding. The oral epithelium and underlying tissues will give rise to the teeth and associated structures. Note: A plane passing through the right and left anterior pillars marks the separation between the oral cavity and oropharynx in the adult.

Embryonic development of the face: give origin and future tissues Stomodeum Mandibular arch (first branchial arch) Maxillary process (es) Frontonasal process Nasal pits Medial nasal process (es) Intermaxillary segment Lateral nasal process (es) Nasolacrimal cord

Ectodermal depression enlarged by disintegration of oropharyngeal membrane Fused mandibular processes and neural crest cells Superior and anterior swelling (s) from mandibular arch and neural crest cells Ectodermal tissue and neural crest cells Nasal placodes Frontonasal process medial to nasal pits Fused medial nasal processes Frontonasal process lateral to nasal pits Nasolacrimal groove Oral cavity proper Lower lip, lower face, mandible with associated tissues Midface. Upper lip sides, cheeks, secondary palate, posterior portion of maxilla with associated tissues, zygomatic bones, portion of temporal bones Medial and lateral nasal processes Nasal cavities Middle of nose, philtrum region, intermaxillary segment Anterior portion of maxilla with associated tissues, primary palate Nasal alae Lacrimal sac, nasolacrimal duct

8 What type of cartilage is found in the auricle of the ear, the external auditory meatus, the auditory tube, and the epiglottis? • Hyaline cartilage • Fibrocartilage • Elastic cartilage

Elastic cartilage Remember: Elastic cartilage is similar to hyaline cartilage, except elastic cartilage pos-sesses large numbers of elastic fibers embedded in matrix. Elastic cartilage is very flexi¬ble and is found in the auricle of the ear, the external auditory meatus, the auditory tube, and the epiglottis. Cartilage can develop or grow in size in two different ways: 1. Interstitial growth -- is growth from deep within the tissue by the mitosis of each chondrocyte, producing a large number of daughter cells within a single lacuna, each of which secretes more matrix, thus expanding the tissue. 2. Appositional growth -- is layered growth on the outside of the tissue from an outer layer of chondroblasts within perichondrium. Growth of bone: • Appositional growth -- or layered formation of bone along its periphery, is accom-plished by the osteoblasts, which later become entrapped as osteocytes. Because of its rigid structure, interstitial growth is not possible. *** Do not confuse bone growth with bone formation or development. Bone forms by either endochondral ossification or intramembranous ossification.

Topical application of fluoride and more recently amorphous calcium phosphate (ACP) are both treatments to remineralize the hydroxyapatite in which tissue -- the hardest calcified tissue in the human body? • Bone • Dentin • Enamel • Cementum

Enamel Enamel is the hardest calcified tissue in the human body and the richest in calcium. Enamel is highly mineralized and is totally acellular. It consists of approximately 96% inorganic material (primarily calcium and phosphorus as hydroxyapatite), 1% organic material, and 3% water. Enamel is of ectodermal origin. The organic matrix consists mainly of protein, which is rich in proline. The fundamental morphologic unit of enamel is the enamel rod or prism -- bound together by an interprismatic substance (interrod substance). Each is formed in increments by a single enamel-forming cell, the ameloblast. Most enamel rods extend the width of the enamel from the DEJ to the outer enamel surface. Consequently, each enamel rod is oriented somewhat perpendicular to the DEJ and the outer enamel surface. The specific shape of the enamel rod is dictated by the Tomes' process of the ameloblast. In most cases, each enamel rod is cylindrical in the longitudinal section. In most areas of enamel, the enamel rod is about 4 micrometers in diameter. Note: The oldest enamel in a fully erupted tooth is located at the DEJ underlying a cusp or cingulum. Other important facts about enamel: • It has no power of regeneration -- the ameloblasts lose their functional ability when the crown of the tooth has been completed • It has no power of metabolism • It has no means of combating bacterial invasion -- the susceptibility of the min¬eral component to dissolution in an acid environment is the basis for dental decay • It has no nerve supply • It is a good thermal insulator • The acid solubility of the surface enamel is reduced by fluoride (this is the basis for the topical application of fluorides in dental caries prevention)

Comparison of the Dental Hard Tissues Enamel Dentin Cementum Alveolar Bone Embryological background Type of tissue Inorganic levels Incremental lines Formative cells Resorptive cells Organic and wa- ter levels Tissue formation after eruption Vascularity Innervation

Enamel organ Epithelial 96% Lines of Retzius Ameloblasts Odontoclasts 1% organic and 3% water None None None Dental papilla Connective tissue 70% Imbrication lines of von Ebner Odontoblasts Odontoclasts 20% organic and 10% water Possible None Present Dental papilla Connective tissue 65% Arrest and rever- sal lines Cementoblasts Cementoclasts 23% organic and 12% water Possible None None Mesoderm Connective tissue 60% Arrest and reversal lines Osteocytes Osteoclasts 25% organic and 15% water Possible Present Present

The reduced enamel epithelium forms as the collapse of what structure? ) • Cervical loop • Hertwig's epithelial sheath • Enamel organ • Dental lamina

Enamel organ Following the formation of the crown, the enamel organ (the inner and outer enamel epithelium, stratum intermedium, and stellate reticulum) collapses to form the reduced enamel epithelium that covers the tooth through eruption. The reduced enamel epithelium consists of the mature/protective ameloblasts and remnants of the outer layers of the enamel organ. Numerous capillaries, which had formed to supply oxygen and nutrients to the ameloblasts following dentin formation, surround the reduced enamel epithelium. The reduced enamel epithelium is important in the formation of the dentogingival junction, which is an area where the enamel and oral epithelium come together as the tooth erupts into the mouth. This forms the initial junctional epithelium (or epithelial attachment), which later migrates down the tooth to assume its normal position. Remember: The junctional epithelium (or epithelial attachment) attaches the gingival tissues to the tooth using hemidesmosomes. The apical extent of the junctional epithelium is usually the cementoenamel junction.

The formation of osseous tissue, which is responsible for the increase in the length of long bones and the healing of bone fractures, occurs due to: i • Endochondral ossification • Heterotopic ossification • Intramembranous ossification

Endochondral ossification Endochondral ossification begins with points in the cartilage called "primary ossification centers." They mostly appear during fetal development, though a few short bones begin their primary ossification after birth. They are responsible for the formation of the diaphyses of long bones, short bones, and certain parts of irregular bones. "Secondary ossification" occurs after birth, and forms the epiphyses of long bones and the extremities of irregular and flat bones. The diaphyses and the epiphyses of long bones remain separated by a growing zone of cartilage (the metaphysis) until the child reaches adulthood (18 to 25 years of age), whereupon the cartilage ossifies, fusing the two together. Note: Heterotopic ossification is the formation of bone outside the skeleton and is seen in diseases such as myositis ossificans. Long bones increase in length during growth and development. The epiphyseal plate (disc) is a wedge of hyaline cartilage accounting for this increase. This plate is found be¬tween the epiphysis (bulbous end) and diaphysis (tubular shaft) at each end of the bone. The cartilage cells of the epiphyseal plate form layers of compact bone tissue, adding to the length of the bone (interstitial growth). This disc becomes inactive in most individu¬als by the late teens or early twenties. Remember: Bone formation or development occurs by two methods: 1. Intramembranous ossification mainly occurs during formation of the flat bones of the skull; the bone is formed from mesenchyme tissue. 2. Endochondral ossification occurs in long bones, such as limbs; the bone is formed from cartilage.

The connective tissue layer surrounding each individual muscle fiber is called the: • Perimysium • Epimysium • Endomysium

Endomysium As an organ, skeletal muscle consists of several tissue types. Skeletal muscle fibers are long, thread-like cells that compose skeletal (striated) tissue. These cells have the ability to shorten their length or contract. Dense fibrous connective tissue (fascia) weaves through a skeletal muscle at several different lev¬els. • The epimysium is the connective tissue layer that envelopes the entire skeletal muscle • The perimysium is a continuation of this outer fascia, dividing the interior of the muscle into bundles of muscle cells. The bundle of cells surrounded by each perimysium is called a fasci¬culus • The endomysium is a connective tissue layer surrounding each muscle fiber Each of the three levels of fascia is interconnected, allowing vessels and nerves to reach individ¬ual fibers and cells. Note: The axon of a motor neuron is highly branched, and one motor neuron innervates num¬erous muscle fibers. When a motor neuron transmits an impulse, all of the fibers it innervates contract simultaneously.

The shaft of a long bone is capped on the end by spongy bone that is surrounded by compact bone. This is called the:

Epiphysis: Long bones have a tubular shaft, the diaphysis, and usually an epiphysis at each end. During the growing phase, the diaphysis is separated from the epiphysis, by an epiphyseal cartilage. The part of the diaphysis that lies adjacent to the epiphyseal cartilage is called the metaphysis. The shaft has a central marrow cavity containing bone marrow. The outer part of the shaft is composed of compact bone that is covered by a connective tissue sheath, the periosteum.

Which cranial nerve supplies the derivatives of the second branchial arch? ) • Glossopharyngeal (CN IX) • Trigeminal (CN • Vagus (CN A) • Facial (CN VII)

Facial (CN VII) Note: The trigeminal, facial, glossopharyngeal, and vagus nerves are said to be branchiomeric (non-somitic) in origin because they originate from the branchial arches.

The human body contains four basic types of tissue. Which type is classified according to the number of cell layers and the shape of the cells on its surface? • Nervous tissue • Muscle tissue • Connective tissue • Epithelial tissue

Epithelial tissue Simple: single layer of cells • Squamous epithelium is a single layer of flat cells; lines areas in which substances such as gases need to cross readily • Cuboidal epithelium is a single layer of cells of equal height and width; lines areas involved with secretion and absorption • Columnar epithelium is a single layer of cells taller than wide; lines areas of absorp¬tion Stratified: multiple layers of cells • Squamous epithelium lines areas needing protection • Cuboidal epithelium lines areas of mid-sized ducts • Columnar epithelium lines large ducts Specialized epithelium: specialized to undergo distension • Pseudostratified columnar epithelium is specialized for secretion and movement along luminal surfaces (multiple layers of cells) • Transitional epithelium lines areas that accommodate increase in luminal area by changes in cell shape (also has low permeability) -- is a stratified epithelium Connective tissue -- types: • Solid soft: connective tissue proper, specialized (adipose, fibrous, elastic, reticular) • Solid firm: cartilage • Solid rigid: bone • Fluid: blood, lymph Muscle -- types: • Involuntary: smooth and cardiac • Voluntary: skeletal Nerve -- types: • Afferent: sensory • Efferent: motor

Heartburn or GERD is a reflux disease associated with substernal burning pain and even metaplasia where the acidic juices of the stomach enter the muscular tube that connects the pharynx to the stomach. This tube is called the: • Ascending colon • Duodenum • Esophagus • Ureter

Esophagus The esophagus is a 10-inch collapsible muscular tube that lies dorsal to the trachea and ventral to the vertebral column. The esophagus is located behind the trachea in the thorax. The esophagus extends from the oropharynx anterior to the vertebral column, enters the mediastinum, leaves the thorax via the esophageal hiatus, and joins the stomach. The point where the esophagus ends and the stomach begins is the esophagogastric junction. The opening through which the abdominal part of the esophagus enters the cardiac portion of the stomach is called the cardiac orifice. Important: There is an abrupt change in the type of surface epithelium at the junction of the esophagus and stomach -- from stratified squamous to simple columnar. The esophageal wall contains four layers, as follows from the lumen outward: • mucosa - epithelium, lamina propria, and glands • submucosa - connective tissue, blood vessels, and glands • muscularis (middle layer) - upper third, striated muscle; middle third, striated and smooth; lower third, smooth muscle • adventitia - connective tissue that merges with connective tissue of surrounding structures The esophagus receives blood from the inferior thyroid artery, from branches of the descending thoracic aorta, and from branches of the left gastric artery. "GERD" stands for gastroesophageal reflux disease, and "Barrett's esophagus" is the metaplasia, or abnormal change, in the epithelium of the lower end of the esophagus thought to be caused by chronic acid damage. Remember: The esophagus receives parasympathetic fibers from the esophageal branches of the vagus nerve. The esophagus receives motor fibers from the recurrent laryngeal branches of the vagus nerve and sympathetic innervation from the esophageal plexus of nerves.

The internal acoustic meatus transmits which two structures?

Facial nerve (CN VII) -- motor and sensory roots Vestibulocochlear nerve (CN VIII)

Which of the following two sets of muscles raise the ribs during inspiration? • External intercostal muscles • Internal intercostal muscles • Innermost intercostals • Subcostal muscles • Transverse thoracic muscles

External intercostal muscles Subcostal muscles The thorax contains vital structures that enable such functions as breathing to occur. Its major muscles are the thoracic wall and upper limb muscles as well as the diaphragm. Anterior thoracic wall muscles include: • External intercostal muscles: eleven on each side between the ribs. Pass from rib to rib and run at right angles to the fibers of the internal and innermost muscles. Continue toward sternum as the internal intercostal membrane. They raise the ribs during inspiration. • Internal intercostal muscles: eleven on each side between the ribs. They continue toward the vertebral column as the posterior intercostal membrane. They depress the ribs during expiration. • Innermost intercostals: run in the same direction as internal intercostals but are separated from them by nerves and vessels. Action unknown but probably the same as internal intercostals. • Subcostal muscles: originate on the inner surface of each rib near the costal angle and insert on the inner surface of the first, second, or third rib below. They raise the ribs during inspiration. • Transverse thoracic muscles: attach the posterior surface of the lower sternum to the internal surface of costal cartilages 2 through 6. These muscles pull the ribs downward during expiration. Important: These muscles are all innervated by the corresponding intercostal nerves. Remember: The diaphragm is the main muscle responsible for quiet breathing. The diaphragm is innervated by the phrenic nerve.

true or false: The medial pterygoid plates of the sphenoid bone provide attachment sites for two muscles of mastication

FALSE, Remember: The lateral pterygoid plate provides the origin for both the lateral and the medial pterygoid muscles. The sphenoid bone is situated at the base of the skull in front of the temporal and basilar part of the occipital bone. It somewhat resembles a bat with its wings extended, and is divided into a median portion or body, two great and two small wings extending outward from the sides of the body, and two pterygoid processes that project from the bone below. Hollow body: Contains the sella turcica, which houses the pituitary gland and the sphenoidal sinuses. Greater wings: Help to form the lateral wall of the orbit and the roof of the infratemporal fossa. Contain foramen rotundum: transmits maxillary nerve (V-2), foramen ovale: transmits mandibular nerve (V-3), and foramen spinosum: transmits the middle meningeal vessels and nerves to the tissues covering the brain. Lesser (small) wings: Help to form the roof of the orbit and the superior orbital fissure; contain the optic canal (optic foramen) that transmits the optic nerve (CN II) and ophthalmic artery. Pterygoid processes: One on either side, descend perpendicularly from the regions where the body and great wings unite. Each process consists of a medial and a lateral plate, the upper parts of which are fused anteriorly; a vertical sulcus, the pterygopalatinegroove, descends on the front of the line of fusion.

The pterygopalatine ganglion contains preganglionic parasympathetic axons from which cranial nerve? • Oculomotor (CN III) • Facial (CN VII) • Trigeminal (CN V) • Glossopharyngeal (CN IX) • Vagus (CN X)

Facial (CN These four paired ganglia supply all parasympathetic innervation to the head and neck. They are the ciliary gan¬glion, pterygopalatine ganglion, submandibular ganglion, and the otic ganglion. Each has three roots entering the ganglion and a variable number of exiting branches. • The motor root carries presynaptic parasympathetic nerve fibers that terminate in the ganglion by synaps¬ing; the postsynaptic fibers travel to target organs • The sympathetic root carries postsynaptic sympathetic fibers that traverse the ganglion without synapsing • The sensory root carries general sensory fibers that also do not synapse in the ganglion *** Some ganglia also carry special sensory fibers for taste

Which vein communicates with the superior ophthalmic vein and thus with the cavernous sinus, allowing a route of infection from the face to the cranial dural sinus? • Occipital vein • Facial vein • Lingual vein • Posterior auricular vein

Facial vein The facial vein is formed at the medial angle of the eye by the union of the supraorbital and supratrochlear veins. The facial vein is connected to the superior ophthalmic vein directly through the supraorbital vein. By means of the superior ophthalmic, the facial vein is connected to the cavernous sinus. The facial vein descends behind the facial artery to the lower margin of the body of the mandible. The facial vein crosses superficial to the submandibular gland and is joined by the anterior division of the retromandibular vein. The facial vein ends by draining into the internal jugular vein. Important: Danger triangle of the face -- a triangle exists that approximately covers the nose and maxilla and goes up to the region between the eyes. This is an area in which superficial veins communicate with the dural sinuses. *** The facial vein has no valves, and a backflow can cause an infection to get into the dural sinuses, through the deep facial vein (via pterygoid plexus) and superior ophthalmic vein (via cavernous sinus). Anastomoses to remember: 1. Deep facial vein is a communication between the facial vein and the pterygoid plexus. 2. Superior ophthalmic vein is a communication between the facial vein and the cavernous sinus.

Scaling and root planning are periodontal treatments that can remove calculus and also stimulate the gingiva. Usually, a periodontist waits four to six weeks after a scaling and root planning procedure for re-evaluation of therapy. This allows healing of the connective tissue by what main cellular component of the gingival connective tissue? • Osteoblast • 0 dontob I ast • Fibroblast • Ameloblast

Fibroblast All forms of epithelium, whether associated with lining, masticatory, or specialized mu¬cosa, have a lamina propria deep to the basement membrane. The lamina propria, like all forms of connective tissue proper, has two layers: papillary and dense. The lamina propria is densely collagenous with a system of collagen fiber bundles called the gingival fibers (gingival ligament). These fibers brace the marginal gingiva against the tooth, provide the rigidity necessary to withstand the mechanical insults of mastication, and unite the free marginal gingiva with the cementum of the root and adjacent attached gingiva. These fibers are continuous with the periodontal ligament. The PDL is also considered to be connective tissue. It surrounds the root and connects it with the alveolar bone by its principal fibers (alveolodental ligament), which are also collagenous fibers. The most common cell in the lamina propria, like all types of connective tissue proper, is the fibroblast. The fibroblast is responsible for the synthesis and secretion of collagen as well as other proteins. Therefore, fibroblasts are responsible for healing of the gingiva fbllowing surgery or disease processes. Other cells present in the lamina propria in smaller numbers are the white blood cells such as PMNs, mast cells, macrophages, and lymphocytes. Remember: The collagen fibers of the gingiva are called the gingival fiber group or gingival ligament, which consists of five ligaments or groups: the circular ligament, dentogingival ligament, dentoperiosteal ligament, and alveologingival ligament. Note: The gingival apparatus is a term used to describe the gingival ligament (or groups) and the epithelial attachment.

The apex of the heart is located at the level of the: • Third left intercostal space • Fourth left intercostal space • Fifth left intercostal space • Sixth left intercostal space

Fifth left intercostal space The apex of the heart is formed by the tip of the left ventricle and is located at the level of the fifth left intercostal space. The ventricles are larger and thicker walled than the atria. The right ventricle pumps blood to and from the lungs. The left ventricle, larger and thicker walled than the right, pumps blood through all other vessels of the body. Note: The ventricles receive blood from the atria. Important: The left ventricle enlarges briefly in response to coarctation (constriction) of the aorta. Remember: The heart functions as a double pump. The right side (right atrium) receives deoxygenated blood from the systemic circuit via the superior and inferior venae cavae as well as the coronary sinus. The blood then goes from the right atrium to the right ventricle via the right AV valve. The right ventricle then pumps blood into the pulmonary circuit (via the pulmonary semilunar valve, which allows blood to flow into the pulmonary arteries). Note: Resistance to pulmonary blood flow in the lungs causes a strain on the right ventricle and result in ventricular hypertrophy. The left side (left atrium) receives oxygenated blood from the lungs by way of the pulmonary veins. This blood then flows through the left AV valve into the left ventricle. From the left ventricle, blood passes through the aortic valve and enters the arch of the aorta, which will deliver the blood to the body's systemic circuits.

The palate, both hard and soft, begins formation in the: • Third week of prenatal development, within the embryonic period • Fourth week of prenatal development, within the embryonic period • Fifth week of prenatal development, within the embryonic period • Sixth week of prenatal development, within the embryonic period

Fifth week of prenatal development, within the embryonic period The palate is formed from two separate embryonic structures: the primary palate and the secondary palate. The palate is then completed during the 12th week of prenatal devel-opment. The palate is developed in three consecutive stages: • The formation of the primary palate • The formation of the secondary palate • The completion of the palate Primary palate formation: During the fifth week, the intermaxillary segment arises as a result of fusion of the two medial nasal processes within the embryo. The intermaxil¬lary segment gives rise to the primary palate. The primary palate will form the premax¬illary portion of the maxilla (the anterior one-third of the final palate). This small portion is anterior to the incisive foramen and will contain the maxillary incisors. Secondary palate formation: During the sixth week, the bilateral maxillary processes give rise to two palatal shelves, or lateral palatine processes. These two palatal shelves elongate and move medially toward each other, fusing to form the secondary palate. The secondary palate will give rise to the posterior two-thirds of the hard palate, which will contain the maxillary canines and posterior teeth, posterior to the incisive foramen. The secondary palate also gives rise to the soft palate and its uvula. Completion of the palate: To complete the palate, the secondary palate meets the poste¬rior portion of the primary palate, and fuses together. These three processes are completely fused, forming the final palate, both hard and soft portions, during the 12th week of pre-natal development.

A 46-year-old woman comes into the dentist's office for a cleaning. He notice-sN that her tongue is slightly swollen, fiery red, and smooth. Her diet history indicates that she has had a loss of appetite for quite some time and that she has been feeling fatigued. A call to her physician indicates a history of iron deficiency anemia and associated glossitis. In glossitis, the smooth nature is caused by a lack of which papillae that are the most numerous and cover the anterior two-thirds of the tongue? • Foliate • Circumvallate • Fungiform • Filiform

Filiform The dorsum of the tongue is studded with papillae, of which there are four types: • Filiform -- most numerous, small cones arranged in "V"-shaped rows paralleling the sul¬cus terminalis on the anterior two-thirds of the tongue. They are characterized by the absence of taste buds and increased keratinization. They serve to grip food • Fungiform knob-like or mushroom-shaped projections, they are found on the tip and sides of the tongue. These taste buds are innervated by the facial nerve (VII) • Circumvallate (vallate) -- largest but fewest in number, they are arranged in an invert¬ed "V"-shaped row on the back of the tongue. Associated with the ducts of Von Ebner's glands. These taste buds are innervated by the glossopharyngeal nerve (IX) • Foliate -- found on lateral margins as 3 to 4 vertical folds. These taste buds are innervat¬ed by both the facial nerve (VII -- anterior papillae) and the glossopharyngeal nerve (IX -- posterior papillae) The receptors for the sense of taste (gustation) are located in taste buds on the surface of the tongue. The taste buds are associated with peg-like projections on the tongue mucosa called lingual papillae. A taste bud contains a cluster of 40 to 60 gustatory cells, as well as many more supporting cells. Each gustatory cell is innervated by a sensory neuron. The tongue and the roof of the mouth contain most of the receptors for the taste nerve fibers in branches of the facial, glossopharyngeal, and vagus nerves. Located on taste cells in the taste buds, these receptors are stimulated by chemicals. They respond to four taste sensa¬tions perceived by specific areas on the tongue: • sweet: on the tip • bitter: on the back • sour: along the sides • salty on the tip and sides The underside of the tongue is soft and kept very moist by salivary gland secretions. Beneath the tongue lie the openings of the ducts from the sublingual and submandibular glands. The frenulum forms the midline ridge on the lower surface of the tongue. The paired deep arter¬ies and veins of the tongue lie on each side of this ridge.

Surface Features of Bone: depressions

Fissure (a sharp, deep groove): a sharp, narrow, cleft-like opening between the parts of a bone that allows for the passage of blood vessels and nerves Example: superior orbital fissure of the sphenoid. Sulcus (a groove, but shallower and a less abrupt cleft than a fissure): a shallow, wide groove on the surface of a bone that allows for the passage of blood vessels, nerves, and tendonsExample: Intertubercular sulcus of the humerus, alternately known as the bicipital groove.Incisure (notch): a deep indentation on the border of a bone Example: greater sciatic incisure or notch of the os coxaFovea: a small, very shallow depressionExample: fovea capitis on the head of the femur accepts a ligament from the hip socket or acetabulum.Fossa: a shallow depression. This may or may not be an articulating surface Example (of articulating surface): Glenoid fossa of the scapula or mandibular fossa of the temporal bone. Example (non-articulating surface): subscapular fossa.

bones of skull

Fitting together to form a protective shell, the skull is composed of paired bones on each side, and unpaired bones running through its midline. The seven unpaired bones are the frontal, ethmoid, occipital, sphenoid, mandible, vomer, and hyoid bones. The 10 paired bones are the temporal bones, including the tiny middle ear bones (ossicles) of the malleus, incus, and stapes (hammer, anvil, and stirrup), parietal, lacrimal, nasal, zygomatic, palatine, and maxillary bones.

A young couple looking to have a baby goes to a fertility clinic. The reason they are having trouble conceiving is because the man's sperm is incompetent and are relatively non-motile. In vitro fertilization is indicated and will most likely be successful. What is the long, whip-like organelle that sperm use to move about? • Centriole • Flagellum • Vacuole • Cilium

Flagellum Flagella are present in the human body only in the spermatozoa. Flagella are similar in structure to cilia but are much longer. The action of the flagellum produces movement. The cilium is a short, hair-like projection from the cell membrane. The coordinated beat¬ing of many cilia produce organized movement. The basic structure of flagella and cilia is the same. They resemble centrioles in having nine sets of microtubules arranged in a cylinder. But unlike centrioles, each set is a dou¬blet rather than a triplet of microtubules, and two singlets are present in the center of the cylinder. At the base of the cylinders of cilia and flagella, within the main portion of the cell, is a basal body. The basal body is essential to the functioning of the cilia and fla¬gella. From the basal body, fibers project into the cytoplasm, possibly to anchor the basal body to the cell. Both cilia and flagella usually function either by moving the cell or by moving liquids or small particles across the surface of the cell. Flagella move with an undulating snake-like motion. Cilia beat in coordinated waves. Both move by the contraction of the tubular proteins contained within them.

In the fetal heart, the permits blood flow from the right atrium to the left atrium. • Fossa ovalis • Foramen ovale • Foramen rotundum • Ductus arteriosus • Ductus venosus

Foramen ovale Remember: In the fetal heart, the foramen ovale permits blood to flow from the right atrium to the left atrium. The blood will then pass to the left ventricle and the aorta, thereby bypassing the non-functional fetal pulmonary circuit. Eventually, the foramen ovale becomes permanently closed with fibrous connective tissue and becomes the fossa ovalis in the adult. The fossa ovalis is situated at the lower part of the atrial septum, above and to the left of the orifice of the inferior vena cava. The annulis ovalis forms the upper margin of the fossa. The atrial portion of the heart has relatively thin walls and is divided by the atrial septum into the right and left atria. The ventricular portion of the heart has thick walls and is divided by the ventricular septum into right and left ventricles. Note: The ligamentum arteriosum is a remnant of the ductus arteriosus in the fetus. The ductus arteriosus is a normal fetal structure, allowing blood to bypass circulation to the lungs (blood is shunted from the pulmonary artery to the aortic arch). Since the fetus does not use his or her lungs (oxygen is provided through the mother's placenta), flow from the right ventricle needs an outlet. The ductus provides this, shunting flow from the left pulmonary artery to the aorta just beyond the origin of the artery to the left subclavian artery. The high levels of oxygen that the ductus is exposed to after birth causes the ductus to close in most cases within 24 hours. When it doesn't close, it is termed a patent ductus arteriosus. After birth, the ductus arteriosus becomes the ligamentum arteriosum, which connects the arch of the aorta to the left pulmonary artery.

Surface Features of Bone: openings

Foramen: an opening through which blood vessels, nerves, or ligaments pass Example: Foramen magnum of the occipital bone, mental foramen of the mandible. Meatus (canal): a tube-like passage running through a bone

Which four major arteries supply the brain with blood

Four major arteries, the two vertebral and the two carotid, supply the brain with oxygenated blood. The two vertebral arteries (which are branches of the subclavians) converge to become the basilar artery, which supplies the posterior brain.

Which pharyngeal pouch gives rise to the inferior parathyroid gland and the thymus gland? • First • Second • Third • Fourth

Fourth Four well-defined pairs of pharyngeal pouches develop as endodermal evaginations from the lateral walls lining the pharynx. The pouches develop as balloon-like structures in a craniocaudal sequence between the branchial arches. Note: The fifth pharyngeal pouches are absent or rudimentary

Comparison of Arteries, Capillaries, Veins Blood direction Muscle layer Semilunar valves Pressure Oxygen concentration

From heart Thick elastic None High with pulse Oxygenated Joins arteries to veins None None Less, no pulse Mixture To heart Thin elastic Present Very low with pulse Deoxygenated

A patient comes to the emergency room presenting with jaundice and intense\ pain in the upper abdominal and between the shoulder blades. The physician suspects choledocholithiasis that is caused by cholesterol stones formed in which organ that stores and concentrates the bile. • Appendix • Gallbladder • Pancreas • Spleen

Gallbladder The gallbladder is a sac-shaped organ roughly 3 to 4 inches long. It is firmly attached to the lower surface of the liver and lies on the right side of the abdomen just below the ribs at the front. The gallbladder is joined by the cystic duct to the biliary ducts of the liver. The common bile duct passes down through the head of the pancreas to drain into the duodenum at the duodenal ampulla. Just before the duct enters the duodenum, the com¬mon bile duct is joined by the main duct of the pancreas. Note: The gallbladder's lining is folded into rugae (similar to those in the stomach). The middle layer consists of smooth muscle fibers that contract to eject bile. Bile is continuously produced by the liver and drains through the hepatic ducts and bile duct to the duodenum. When the small intestine is empty of food, the sphincter (Oddi's sphincter) of the hepatopancreatic ampulla (ampulla of Vater) constricts, and bile is forced up the cystic duct to the gallbladder for storage. Important: Secretion of the hormone cholecystokinin after a fatty meal stimulates gall¬bladder contraction and relaxation of Oddi's sphincter, and the bile mixes with the chyme. 1. The sphincter (Oddi's sphincter) of the hepatopancreatic ampullaris is a cir¬cular muscle that surrounds the hepatopancreatic ampulla (ampulla of Vater). 2. The gallbladder does not contain a submucosa as do the stomach and intes¬tines (both large and small). 3. Bile emulsifies neutral fats and absorbs fatty acids, cholesterol, and certain vitamins. 4. The gallbladder receives blood from the cystic artery, a branch of the right hepatic artery. The gallbladder is innervated by vagal fibers from the celiac plexus. The lymph drains into a cystic lymph node, then into the hepatic nodes, and eventually into the celiac nodes.

Proteinaceous tubes that connect adjacent cells are called: 1p • Tight junctions • Hemidesmosomes • Gap junctions • Adherens junctions

Gap junctions Gap junctions are proteinaceous tubes some 1.5 to 2 nm in diameter. These tubes allow material to pass from one cell to the next without having to pass through the plasma membranes of the cells. Dissolved substances such as ions or glucose can pass through the gap junctions. They are formed by transmembrane proteins called connexins. Gap junctions are separate from the components of the junctional complexes. gap junctions facilitate cell-to-cell communication. Note: Because ions can flow through gap junctions, they permit changes in the membrane potential to pass from cell to cell. Functionally, there are three groups of cell junctions: 1. Occluding junctions -- which join the plasma membranes of adjacent cells tightly together. 2. Anchoring junctions -- which physically connect adjacent cells and their cyto-skeletons, but leave a space separating the plasma membranes. 3. Communicating junctions -- which permit the passage of chemical and electrical signals between the joined cells. Gap junctions belong to this group. Such specialized cell junctions are found in many tissues throughout the body, but are es¬pecially abundant in epithelial tissues, where some cell junctions are organized into groups called junctional complexes. Three distinct components of a junctional complex: • A tight junction • An intermediate junction • A desmosome *** All of which are associated with the plasma membranes of adjacent cells

I A 5-year-old boy presents to the physician with tonsillitis. As part of her exam, the physician asks the patient to stick out his tongue and say "AAAH," in order to visualize the tonsils. Which muscle is responsible for the protraction of tongue? • Hyoglossus • Styloglossus • Palatoglossus • Genioglos sus

Genioglossus Paired extrinsic muscles originate on structures away from the tongue and insert onto it, causing tongue movements during speaking, manipulating food, cleansing teeth, and swallowing.

A gag reflex overcomes your patient as you lightly swab an area of the ..,, oropharynx. What nerve carries the sensory fibers of this reflex? i • Trigeminal nerve (CN V) • Facial nerve (CN VII) • Glossopharyngeal nerve (CN IX) • Vagus nerve (CN X)

Glossophar■ ngeal nerve (CA' IX) The glossopharyngeal nerve is a mixed nerve (motor and sensory), which originates from the anterior surface of the medulla oblongata along with the vagus nerve (CN X) and spinal accessory nerve (CN Xl). The glossopharyngeal nerve passes laterally in the posterior cranial fossa and leaves the skull through the jugular foramen to supply sensation to the pharynx and posterior third of the tongue. The cell bodies of these sensory neurons are located in the superior and inferior ganglia of this nerve. The glossopharyngeal nerve then descends through the upper part of the neck along with the internal jugular vein and internal carotid artery to reach the posterior border of the stylopharyngeus muscle of the pharynx to which the nerve supplies somatic motor fibers. Note: The glossopharyngeal nerve carries primary afferent neurons to the gag reflex (the glossopharyngeal nerve innervates the mucous membranes of the fauces). The otic ganglion is a small parasympathetic ganglion that is functionally associated with the glossopharyngeal nerve. The otic ganglion is located immediately below the foramen ovale in the infratemporal fossa. The otic ganglion is one of four parasympathetic ganglia of the head and neck. (the others are the submandibular ganglion, pterygopalatine ganglion, and ciliary ganglion). The tympanic and lesser petrosal branches of the glossopharyngeal nerve supply preganglionic parasympathetic secretomotor fibers to the otic ganglion. Here the fibers synapse, and the postganglionic fibers leave the ganglion and join the auriculotemporal nerve. As the auriculotemporal nerve passes the parotid gland, postganglionics leave the nerve to enter the substance of the gland. Important: Terminal ganglia receive preganglionic fibers from the parasympathetic division. The following cranial nerves also contain preganglionic parasympathetic fibers: oculomotor (ciliary ganglion), facial (pterygopalatine and submandibular ganglia), and vagus (small terminal ganglia).

What structures act as "molecular sponges" and hold water in the extracellular matrix of cartilage? • Glycosaminoglycans • Glycoproteins • Oxytalans • Elaunins

Glycosaminoglycans Cartilage matrix is a homogeneous material principally composed of proteoglycans, macromolecules with a proteinaceous backbone, to which is attached complex carbohydrates (these carbohydrates are "glycosaminoglycans," usually abbreviated GAGs). The GAGs radiate from the protein core like the bristles of a bottle brush. The principal GAGs of cartilage are chondroitin sulfate and keratan sulfate. Another matrix component is hyaluronic acid, a gelatinous mucopolysaccharide. The hyaluronic acid acts as a sort of cement to bind the proteoglycans together into large aggregates. Important: Because of the chemical nature and organization of the glycosaminogly-cans, the ground substance can readily bind and hold water, which allows the tissue to assume a gelatinous nature that can resist compression and permit some degree of diffusion through the matrix. Note: Chondrocytes produce all the components of cartilage: the matrix material and the fibers as well. Hyaline cartilage forms nearly all of the fetal skeleton. In the adult, the remnants are: • Articular cartilage -- smooth and slippery, it lines movable joints • Costal cartilages -- at the sternal ends of the ribs • Respiratory cartilages -- movable external nose and septum, larynx, trachea, and bronchial walls • Auditory cartilages -- external auditory meatus and pharyngotympanic tube

Neuron cell bodies are located in: • White matter of the spinal cord • Meninges • Gray matter of the spinal cord

Gray matter of the spinal cord The spinal cord extends from the base of the skull to a point above two-thirds of the way down the back, running through the vertebral canal. Within the spinal cord, the H-shaped mass of gray matter is divided into horns, which consist mainly of neuronal cell bodies and an intermediate zone. • Posterior (dorsal) horns: are specialized to process sensory information such as touch, pain, and joint sensation, and to relay this information to the brain • Anterior (ventral) horns: contain motor neurons, which transmit messages out to the muscles via spinal nerves An intermediate zone: contains many intemeurons that are involved in linking incoming sensory neurons with outgoing motor neurons to bring about automated (reflex) responses that do not involve the brain. White matter surrounding the outer part of these horns consists of myelinated nerve fibers grouped functionally in vertical columns, or tracts. Important: The cell bodies of the somatic motor system lie within the anterior or ventral horn. The cell bodies of the somatic sensory system lie within the posterior or dorsal horn. The nerves that lie within the spinal cord are upper motor neurons (UMNs), and their function is to carry the messages back and forth from the brain to the spinal nerves along the spinal tract. The spinal nerves that branch out from the spinal cord to the other parts of the body are called lower motor neurons (LMNs). These spinal nerves exit and enter at each vertebral level and communicate with specific areas of the body. The sensory portions of the LMN carry messages about sensation from the skin and other body parts and organs to the brain. The motor portions of the LMN send messages from the brain to the various body parts to initiate actions such as muscle movement. Important: Sympathetic preganglionic neuron routes • Preganglionic neurons may do one of three things: 1. Enter the paravertebral ganglion at the same level via the white ramus communicans and synapse there. 2. Enter the paravertebral ganglion and either ascend or descend to another level to synapse at that level. 3. Pass through the paravertebral ganglion via the white ramus communicans and synapse in a pre-vertebral ganglion.

Which hormone is the most plentiful anterior pituitary hormone and is also-controversial for use in athletic sports and body building? • Follicle stimulating hormone (FSH) • Luteinizing hormone (LH) • Prolactin • Growth hormone (GH) • Thyroid-stimulating hormone (TSH) • Adrenocorticotropic hormone (ACTH)

Growth hormone (GH) Remember: The anterior pituitary gland makes four tropic hormones -- FSH, LH, ACTH, and TSH. This gland also makes two regular hormones -- GH and prolactin. Growth hormone (also called somatotropin) targets most body cells, especially those in the bones and muscles. It accelerates body growth, stimulates cellular uptake of amino acids and protein synthesis, and stimulates carbohydrate and fat breakdown. Prolactin promotes breast development and stimulates milk development. Prolactin release is triggered by rising levels of estrogen.

A physician determines that a patient with acromegaly will develop a skeletal class III occlusion due to excessive growth of the mandible. What causes the formation of resting lines as seen in the cortical bone of the mandible? • Growth of the mandible by appositional growth • Growth of the mandible by interstitial growth • Growth of the mandible by both interstitial and appositional growth

Growth of the mandible by appositional growth Remember: 1. Bone apposition is the deposition of successive layers of bone on those already pres-ent. 2. Due to its rigid structure, bone can grow only by appositional growth. However, cartilage can grow by both appositional and interstitial growth. Remember also that both the maxilla and mandible develop from tissues of the first branchial arch, or mandibular arch. The maxilla forms within the maxillary process, and the mandible forms within the fused mandibular processes of the mandibular arch. Both bones start as small centers of intramembranous ossification.

A 47-year-old patient with pancreatic cancer is put on multiple chemotherapeutic drugs. Unfortunately, as a side effect of the drugs, his kidneys start shutting down, and this leads to hypervolemia, or excess extracellular fluid. Extracellular fluid: • Is composed mainly of transcellular fluids • Makes up the major proportion of total body water • Has a higher sodium/potassium ratio than intracellular fluid • Contains less glucose than intracellular fluid

Has a higher sodium/potassium ratio than intracellular fluid *** Extracellular fluid (Na' - 142, K+- 4) vs. Intracellular fluid (Na' - 10, K - 140) The body's water is effectively compartmentalized into several major divisions. • Intracellular fluid (ICF) comprises two-thirds of the body's water - If your body has 60% water, ICF is about 40% of your weight. - The ICF is primarily a solution of potassium and organic anions, proteins, etc. (Cellular Soup!) - The cell membranes and cellular metabolism control the constituents of this ICF. - ICF is not homogeneous in the body. ICF represents a conglomeration of fluids from all the different cells. • Extracellular fluid (ECF) is the remaining one-third of the body's water - ECF is about 20% of your weight. - The ECF is primarily a NaCI and NaHCO3 solution. - The ECF is further subdivided into three subcompartments: • Interstitial Fluid (ISF) surrounds the cells, but does not circulate. It comprises about three-quarters of the ECF • Plasma circulates as the extracellular component of blood. It makes up about one-quarter of the ECF • Transcellular fluid is a set of fluids that are outside of the normal compart-ments. These 1-2 liters of fluid make up the CSF, digestive juices, mucus, etc. Note: The epidermis of the skin obtains nourishment by diffusion of tissue fluid from cap¬illary beds located in the dermis. This tissue fluid (also called interstitial fluid) contains a small percentage of plasma proteins of low molecular weight that pass through the cap¬illary walls as a consequence of the hydrostatic pressure of the blood. This fluid bathes the cells.

Which artery supplies the liver with oxygenated blood?

Hepatic artery -- arises from the common hepatic, which, in turn, is a branch of the celiac trunk

A chronic alcoholic is starting to show signs of cirrhosis and liver failure. Which of the following cell types will start to become ineffective in manufacturing albumin, fibrinogen, and the prothrombin group of clotting factors? • Fibroblasts • Hepatocyte • Kupffer cell • Erythrocyte

Hepatocyte The liver's functional unit, the lobule, consists of plates of hepatic cells, or hepatocytes, that encircle a central vein and radiate outward. Separating the hepatocyte plates from each other are sinusoids, the liver's capillary system. Hepatocytes make up 60% to 80% of the cytoplasmic mass of the liver. These cells are involved in protein synthesis, protein storage and transformation of carbohydrates, synthesis of cholesterol, bile salts and phospholipids, and detoxification, modification, and excretion of exogenous and endogenous substances. The hepatocyte also initiates the formation and secretion of bile. Hepatocytes have abundant organelles that perform their numerous functions. Smooth endoplasmic reticulum produces bile salts and detoxifies poisons. Peroxisomes also detoxify poisons. Rough endoplasmic reticulum produces blood proteins. The Golgi apparatus packages bile and other secretory products of the cell. Glycosomes store sugar. Finally, numerous mitochondria fuel cell activity. Kupffer cells are reticuloendothelial macrophages, which line the sinusoids. They function to remove bacteria and toxins that have entered the blood through the intestinal capillaries. These cells have definite cytologic characteristics such as clear vacuoles, lysosomes, and granular endoplasmic reticulum.

Which structure functions to shape the root (or roots) and induce dentin formation in the root area so that it is continuous with coronal dentin? j • Dental papilla • Dental lamina • Dental sac • Hertwig's sheath • Enamel

Hertwig's sheath The structure responsible for root development is the cervical loop. The cervical loop is the most cervical portion of the enamel organ, a bilayer rim that consists of only inner and outer enamel epithelium of the enamel organ. The cervical loop begins to grow deeper into the surrounding mesenchyme of the dental sac, elongating and moving away from the newly completed crown area to enclose more of the dental papilla tissue and form Her-twig's epithelial root sheath (HERS). Hertwig's sheath is an epithelial diaphragm that is derived from the inner and outer enamel epithelium of the enamel organ. After crown formation, the root sheath grows down and shapes the root of the tooth and induces formation of root dentin. Uniform growth of this sheath will result in the formation of a single-rooted tooth, while medial outgrowths or evaginations of this sheath will produce multi-rooted teeth. After the first root dentin is deposited, the cervical portion of Hertwig's epithelial root sheath breaks down, and this new dentin comes in contact with the dental sac. This communication stimulates cells to differentiate into cementoblasts that produce cementum. This process is called cementogenesis. Note: Accessory root canals are formed by a break or perforation in the root sheath before the root dentin is deposited.

A chromosome is maximally condensed chromatin wrapped around a protein base of primarily: • Hydroxyapatite • Hyaluronan • Histones • Haploid

Histones Chromosomes are maximally condensed forms of chromatin. Chromatin consists of strands of DNA wound around a protein base of primarily histones and looks like a beaded string under an electron microscope. Chromatin occurs in two forms: euchromatin (extended) and heterochromatin (condensed). When a cell prepares to divide, the chromatin coils into compact chromosomes. Except in the gametes (germ cells), chromosomes appear in pairs. One chromosome from each pair comes from the male germ cell (sperm), the other from the female germ cell (ovum). Normal human cells contain 23 pairs of chromosomes, which makes the diploid number 46. The diploid number is the number of chromosomes of a normal cell. The haploid number is the number of chromosomes in a gamete. Usually, the diploid number is twice the haploid number. In these cells, 22 pairs are called homologous chromosomes or autosomes. These sets contain genetic information that controls the same characteristics or functions. The 23rd pair are sex (X and Y) chromosomes. The composition of these chromosomes determines gender: XX produces a genetic female; XY, a genetic male.

Meibomian glands (or tarsal glands) are sebaceous glands located at the rim of the eyelid that function to protect the eyes from drying out. Meibomian glands, which release the entire secretory cell with the sebum secretion, are this type of gland. • Merocrine • Apocrine • Holocrine

Holocrine Exocrine glands have a duct through which their product (sweat, saliva, digestive enzymes, etc.) is released. Exocrine glands within the integumentary system include sebaceous glands (which are associated with hair follicles and are derived from ectoderm), sweat glands, and mammary glands. Within the digestive system, exocrine glands include the salivary glands, gastric glands within the stomach, and the exocrine portion of the pancreas.Endocrine glands secrete their products (hormones) into the 'nterstitial fluid surrounding the secretory cells from which they diffuse into capillaries to be carried away by the blood. Endocrine glands constitute the endocrine system and include the pituitary, thyroid, parathyroid, adrenal, and pineal glands as well as the gonads and the islets of Langerhans (exocrine cells of the pancreas). The major salivary glands (parotid, submandibular, and sublingual) are classified as compound tubuloalveolar glands. They deliver their salivary secretions into the mouth by way of large excretory ducts (Stensen's, WhartonS., and the numerous small Rivinus's ducts) respectively. Note: The parotid gland and von Ebner's glands are the only adult salivary glands that are purely serous.

incisive foramen

Immediately behind the incisor teeth is the incisive foramen. In this foramen are two lateral apertures, the openings of the incisive canals (foramina of Stenson), which transmit branches of the sphenopalatine artery, and the nasopalatine nerves. Occasionally, two additional canals are present in the incisive foramen; they are termed the foramina of Scarpa and are situated in the middle line; when present, they transmit the nasopalatine nerves.

Branches in the infratemporal fossa:

Inferior alveolar artery: follows the inferior alveolar nerve into the mandibular canal and supplies tissues of the chin and lower teeth. Middle meningeal artery: an important artery that passes upward behind the mandibular nerve. The arteryenters the skull through the foramen spinosum. This artery supplies the meninges within the skull. Note: Damage results in an epidural hematoma.. Small branches that supply the lining of the external auditory meatus and the tympanic membrane. Numerous small muscular branches that supply the muscles of mastication Branches in the pterygopalatine fossa:. Posterior superior alveolar artery: supplies the maxillary sinus and the molar and premolar teeth. Infraorbital artery: enters the orbital cavity through the inferior orbital fissure. Greater palatine artery: supplies the mucosa of the hard palate posterior to the maxillary canine. Pharyngeal branch: supplies the mucous membrane of the roof of the nasopharynx. Sphenopalatine artery: supplies the mucous membrane of the nasal cavity. It is the terminal branch of the maxillary artery. Note: Damage results in epistaxis (nosebleed). Note: The lateral pterygoid muscle divides the maxillary artery into three sections: the mandibular, pterygoid, and pterygopalatine.

Which of the following receives the opening of the nasolacrimal duct?

Inferior meatus: The nasal conchae are three pairs of scroll-like, delicate shelves or projections, which hang into the nasal cavity from the lateral walls. These projections assist in increasing the surface area within the nasal cavity for filtering, heating, and moistening the air. The superior and middle conchae are part of the ethmoid bone; the inferior conchae are separate bones (also called the inferior turbinates). The space below each concha is referred to as a meatus.

Origin, Insertion, Innervation, Action Posterior Compartment Triceps brachii Long head Lateral head Medial head Anterior Compartment Brachialis Coracobrachialis Biceps brachii Long head Short head

Infraglenoid tubercle of scapula Upper half of posterior surface of shaft of humerus Lower half of poste¬rior surface of shaft of humerus Anterior Compartment: Front of lower half of humerus Coracoid process of scapula Supraglenoid tubercle of scapula Coracoid process of scapula Olecranon process of ulna Anterior Compartment Coronoid process of ulna Medial aspect of shaft of humerus Tuberosity of radius Radial nerve Anterior Compartment Musculocutaneous nerve Musculocutaneous nerve Musculocutaneous nerve Extends the forearm (extensor of the elbow joint) Anterior Compartment Flexor of elbow joint Flexes the arm Supinator of forearm and flexor of elbow joint

Cytoskeletal anchor, transmembrane linker, ties cell to: Desmosomes Hemidesmosomes Adherens junctions

Intermediate filaments Intermediate filaments Actin filaments Cadherin Integrin Cadherin Other cells EC matrix other cells/EC

Location: Sustentacular Pyramidal Endothelial Ependymal Sertoli Ganglionic Globular Prickle Fibroblast Chromaffin Purkinje Goblet Interstitial Islet Juxtaglomerular Mesenchymal

Internal ear (organ of Corti), taste buds, olfactory epithelium Cerebral cortex (cerebrum) Lining blood and lymph vessels, endocardium (inner layer) Lining the brain ventricles and spinal cord Seminiferous tubules of the testis In a ganglion peripheral to the CNS Transitional epithelium (kidney, water, bladder) Stratum spinosum of epidermis Most common cell of connective tissue Adrenal medulla and paraganglia of SNS Cerebellar cortex (cerebellum) Mucous membranes of respiratory and intestinal tracts Connective tissue of ovary and testis Pancreas Renal corpuscle of kidney Found between ectoderm and endoderm of embryos

The plasma membrane (cell membrane): • Surrounds the cell wall and serves to protect the cell from changes in osmotic pressure • Is a polysaccharide-containing structure that functions in attachment to solid surfaces, preventing desiccation, and protection • Is a non-permeable membrane enclosing the cell wall • Is a dynamic, selectively permeable membrane enclosing the cytoplasm

Is a dynamic, selectively permeable membrane enclosing the cytoplasm The plasma membrane (cell membrane) is a thin elastic structure 7.5 to 10 nanometers thick. It is located between the cell wall and the cytoplasm. Normal cell membrane function is essential for passive nutrient diffusion in and out of the cell, as well as for active (i.e., requiring energy) transport across the membrane. The plasma membrane consists of a phospholipid bilayer contain¬ing integral and peripheral proteins. This type of membrane is called a fluid mosaic and is found in both prokaryotic and eukaryotic cells. The cell wall surrounds the plasma membrane and serves to protect the cell from changes in osmotic pressure, anchor flagella, maintain cell shape, and control the transport of molecules into and out of the cell. Structures interior to the cell wall include the plasma membrane, the cyto¬plasm, and cytoplasmic constituents such as DNA, ribosomes, and inclusions. Remember: The mitochondrion is an organelle of the cell cytoplasm that consists of an inner membrane and an outer membrane (as does the nucleus). Mitochondria are the principal ener¬gy source of the cell (major site of ATP production) and are involved in all oxidative processes. They contain cyclic DNA.

A plasma cell: • Is a formative cell present in red bone marrow that gives rise to a specific specialized cell • Is a mature B lymphocyte that is specialized for antibody production • Is a mature T lymphocyte that is specialized for cell-mediated immunity • Is any phagocytic cell of the reticuloendothelial system

Is a mature B lymphocyte that is specialized for antibody production Plasma cells are further differentiated B cells that are very important in the production of antibody. They are rarely found in the peripheral blood. They comprise from 0.2% to 2.8% of the bone marrow white cell count. Mature plasma cells are often oval or fan shaped, measuring 8 to 15 um. Their appearance (on light microscopy) is quite charac¬teristic: they have basophil cytoplasm and an eccentric nucleus, in addition to a pale zone in the cytoplasm that (on electron microscopy) contains an extensive Golgi apparatus. They are found mainly in bone marrow and connective tissue. They have a short lifetime of 5 to 10 days. B cells (B lymphocytes, complete maturation in the bone marrow): produce antibody-mediated immunity. They account for 20% to 30% of circulating lymphocytes and like T lymphocytes become associated with lymphoid organs (lymph nodes, spleen, etc.). As B lymphocytes become sensitized to an antigen, mature B cells develop into plasma cells or become memory B cells. Memory B cells are formed specific to the antigen(s) encountered during the primary immune response; able to live for a long time, these cells can respond quickly upon second exposure to the antigen for which they are specific. T cells (T lymphocytes or thymus-derived lymphocytes): produce cell-mediated immuni-ty. They account for 70% to 80% of circulating lymphocytes and become associated with the lymph nodes, spleen, and other lymphoid tissues. Upon interacting with a specific antigen, T lymphocytes become sensitized and differentiate into several types of daugh¬ter cells. These include memory T cells, which remain inactive until future exposure to the same antigen; killer T cells, which combine with antigen on the surface of the for¬eign cells, causing lysis of the foreign cells and the release of cytokines; and different subsets of helper T cells, which help activate other T lymphocytes.

Which statement concerning the left vagus nerve is false? • It can be cut on the lower part of the esophagus to reduce gastric secretion (termed a vagotomy) • It forms the anterior vagal trunk at the lower part of the esophagus • It passes in front of the left subclavian artery as it enters the thorax • It contains parasympathetic postganglionic fibers • It contributes to the anterior esophageal plexus

It contains parasympathetic postganglionic fibers *** This is false; the vagus nerve carries parasympathetic preganglionic fibers to the thoracic and abdominal viscera. The left vagus nerve enters the thorax in front of the left subclavian artery and behind the left brachiocephalic vein. The nerve then crosses the left side of the aortic arch and is itself crossed by the left phrenic nerve. The left vagus nerve passes behind the root of the left lung, forms the pulmonary plexus, and continues to form the esophageal plexus. The left vagus nerve enters the abdomen in front of the esophagus through the esophageal hiatus of the diaphragm as the anterior vagal trunk (reaches the anterior surface of the stomach). Note: The vagus nerves lose their identity in the esophageal plexus. At the lower end of the esophagus, branches of the plexus reunite to form an anterior vagal trunk (anterior gastric nerve), which can be cut (vagotomy) to reduce gastric secretion. The right vagus nerve crosses the anterior surface of the right subclavian artery and enters the thorax posterior to the right brachiocephalic vein, lateral to the trachea, and just posterior to the arch of the azygos vein. The nerve passes posterior to the root of the right lung, contributing to the pulmonary plexus. The nerve also contributes to the esophageal plexus. The nerve enters the abdomen behind the esophagus through the esophageal hiatus of the diaphragm as the posterior vagal trunk (reaches the posterior surface of the stomach). The vagus nerve (CN X): General functions • Motor to and sensory from the larynx • Motor to all of the muscles of the pharynx except the stylopharyngeus (from CN XI) and all muscles of the soft palate except the tensor veli palatini (from mandibular division of CN 9 • Communicates taste from area around epiglottis • Sensory from external auditory meatus • Afferent from viscera above left (splenic) colic flexure • Parasympathetic to the lungs, heart, stomach, and myenteric plexus

All of the following statements concerning cardiac muscle are true EXCEPT one. Which one is the EXCEPTION? • It makes up the muscular component of the heart known as the myocardium • Cardiac muscle cells are faintly striated, branching cells, which connect by means of intercalated discs to form a functional network • It contracts voluntarily • Its fibers are separate cellular units, which (unlike other striated muscle fibers) don't contain many nuclei • It responds to increased demands by increasing the size of its fiber; this is known as compensatory hypertrophy

It contracts voluntarily *** This is false; it contracts involuntarily. The strength and frequency of the heart beat are controlled by the autonomic nervous system. Both parasympathetic and sympathetic parts of the autonomic nervous system are involved in the control of the heart. The heart is also has an internal nervous system made up of the SA (sinoatrial node) and the AV (atrioventricular) node. The AV bundle (His) leaves the AV node near the lower part of the intera¬trial septum and splits over the upper part of the interventricular septum into a left bundle branch and a right bundle branch. The cardiac muscle is then supplied by branches of the two bundles. Specialized cardiac muscle cells in the wall of the heart rapidly initiate or conduct an electrical im¬pulse throughout the myocardium. The signal is initiated by the sinoatrial (SA) node (pacemaker) and spreads to the rest of the right atrial myocardium directly, to the left atrial myocardium by way of a bundle of interatrial conducting fibers, and to the atrioventricular (AV) node by way of three internodal bundles. The AV node then initiates a signal that is conducted through the ventricular my-ocardium by way of the atrioventricular bundle (bundle of His) and Purkinje fibers. Important: The sinuatrial node, located at junction of the superior vena cava and the right auricle, is the most rapidly depolarizing cardiac muscle tissue of the heart. This is why the SA node is referred to as the "pacemaker" of the heart. Remember: The conducting system of the heart is all modified cardiac muscle fibers and not nerves. The sympathetic fibers arise from segments T2-T4 of the spinal cord and are distributed through the middle cervical and cervico-thoracic (or stellate) ganglia and the first four ganglia of the tho¬racic sympathetic chain. The sympathetic fibers pass into the cardiac plexus and from there to the SA node and the cardiac muscle. The effect of the sympathetic nerves at the SA node is an increase in heart rate. The effect on the muscle is an increase in rise of pressure within the ventricle, thus increasing stroke volume. The vagus nerve provides parasympathetic control to the heart. The effect of the vagus nerve at the SA node is the opposite of the sympathetic nerves; it decreases the heart rate. The vagus nerve also decreases the excitability of the junctional tissue around the AV node, and this re¬sults in slower transmission. Note: Strong vagal stimulation here may produce an AV block.

Surrounding the root of each tooth is a specialized epithelium known as: ) • Connective tissue attachment • Periodontal ligament attachment • Junctional epithelium • Nasmyth's membrane

Junctional epithelium The dentojunctional epithelium is the junction between the tooth surface and the gingival tissues. Together, the sulcular epithelium and junctional epithelium form the dentogingival junctional tissues. They are composed of nonkeratinized stratified squamous epithelium. • Sulcular epithelium (also called crevicular epithelium) -- stands away from the tooth, creating a gingival sulcus, or space that is filled with gingival fluid or crevicular fluid. • Junctional epithelium -- a deeper extension of the sulcular epithelium, the junct-ional epithelium begins at the base of the sulcus. This epithelium is a collar-like band of stratified squamous epithelium that is firmly attached to the tooth surface by way of an epithelial attachment. At the epithelium's beginning, it is approximately 15 to 30 cell layers thick, and at its apical end, the epithelium is only a few cell layers thick. The junctional epithelium consists of two layers: a basal layer and suprabasal layer. Important: The superficial, or suprabasal, epithelial cells of the junctional epithelium provide the hemidesmosomes and an internal basal lamina that create the epithelial attachment. The epithelial attachment is very strong in a healthy state, acting as a type of seal between the soft gingival tissues and the hard tissue surface. *** In ideal gingival health, the junctional epithelium is located entirely on enamel above the cementoenamel junction. Note: Histologically, the best way to distinguish the free gingiva from the epithelial attachment is the fact that the epithelium of the epithelial attachment does not contain rete pegs or connective tissue papillae and the free gingiva does. Rete pegs are epithelial projections that extend into the gingival connective tissue. Connective tissue papillae are connective tissue projections that extend into the overlying epithelium.

All of the following statements concerning the temporalis muscle are true) EXCEPT one. Which one is the EXCEPTION? • It is fan-shaped and originates from the bony floor of the temporal fossa and from the deep surface of the temporal fascia • The anterior and superior fibers elevate the mandible; the posterior fibers retract the mandible • It inserts on the coronoid process of the mandible and the anterior border of the ramus of the mandible • It is innervated by the maxillary division of the trigeminal nerve (V-2) • It is considered to be one of the muscles of mastication

It is innervated by the maxillary division of the trigeminal nerve (V-2) *** This is false; the temporalis muscle is innervated by the deep temporal nerves, which are branches of the mandibular division of the trigeminal nerve (V-3). The temporalis muscle is a broad, fan-shaped muscle of mastication on each side of the head that fills the temporal fossa, superior to the zygomatic arch. This muscle originates from the entire temporal fossa. The temporalis then passes medially (downward and deep) to the zygomatic arch as a thick tendon before inserting on the coronoid process 1. The primary function of the anterior portion (fibers) of the temporalis Notes, muscle is to elevate the mandible. 2. The posterior fibers retract the jaw and maintain the resting position of closure of the mouth.

When trying to locate the parotid duct, a freshmen dental student in anatomy class would consider each of the following relationships EXCEPT one. Which one is the EXCEPTION? • Its opening can be seen in the vestibule of the mouth opposite the maxillary second molar tooth • It extends from the anterior border of the parotid gland • It can be palpated as it crosses the face, superficial to the masseter muscle • It is superior to the zygomatic arch

It is superior to the zygomatic arch -- it is actually inferior to the zygomatic arch The parotid gland is the largest of the salivary glands and is a purely serous gland. It is situated below the external auditory meatus and lies in a deep hollow behind the ramus of the mandible and in front of the sternocleidomastoid. This gland is divided into deep and superficial lobes (which enclose the facial nerve). Therefore, a portion of the parotid lies superficial to the mandibular ramus, and another portion lies deep. The parotid gland is drained by Stensen's duct, which crosses the masseter muscle and pierces the buccinator muscle to open into the vestibule of the mouth opposite the maxillary second molar. Parasympathetic secretomotor fibers from the inferior salivary nucleus of the glossopharyngeal nerve supply the parotid gland. The nerve fibers pass to the otic ganglion via the tympanic branch of the glossopharyngeal nerve and the lesser petrosal nerve. Postganglionic parasympathetic fibers reach the parotid gland via the auriculotemporal nerve (branch of V-3), which lies in contact with the deep surface of the gland. The external carotid artery and its terminal branches within the gland, namely the superficial temporal and the maxillary arteries, supply the parotid gland. The lymphatic vessels drain into the parotid lymph nodes and the deep cervical lymph nodes.

( All of the following statements concerning the hypoglossal nerve (CN XII) are true EXCEPT one. Which one is the EXCEPTION? • It is a motor nerve supplying all of the intrinsic and extrinsic muscles of the tongue, except the palatoglossus, which is supplied by the vagus nerve • It leaves the skull through the jugular foramen medial to the carotid canal • It passes above the hyoid bone on the lateral surface of the hyoglossus muscle deep to the mylohyoid muscle • It loops around the occipital artery and passes between the external carotid artery and internal jugular vein • Soon after it leaves the skull through the hypoglossal canal, it is joined by Cl fibers from the cervical plexus

It leaves the skull through the jugular foramen medial to the carotid canal *** This is false; it leaves the skull through the hypoglossal canal medial to the carotid canal and jugular foramen. Note: The jugular foramen allows for the exit of the spinal accessory nerve from the cranial cavity. Important: The hypoglossal nerve travels from the carotid triangle into the submandibular triangle of the neck. Lesions of the hypoglossal nerve: • Unilateral lesions of the hypoglossal nerve result in the deviation of the protruded tongue toward the affected side. This is due to the lack of function of the genioglossus muscle on the diseased side • Injury of the hypoglossal nerve eventually produces paralysis and atrophy of the tongue on the affected side with the tongue deviated to the affected side. Dysarthria (inability to articulate) may also be found Important: If the genioglossus muscle is paralyzed, the tongue has a tendency to fall back and obstruct the oropharyngeal airway with risk of suffocation.

Superior orbital fissure transmits to:

It transmits the: • superior and inferior divisions of the oculomotor nerve (CN III) trochlear nerve (CN IV) lacrimal, frontal, and nasociliary branches of the ophthalmic nerve (CN V1) abducent nerve (CN VI) superior and inferior divisions of the ophthalmic vein sympathetic fibers from the cavernous plexus

All of the following statements concerning the liver are true EXCEPT one. Which one is the EXCEPTION? • It receives blood from the hepatic artery and portal vein • It receives autonomic nerve fibers from the celiac plexus • Its function is to store and concentrate bile • It is the body's heaviest and most active internal organ • The caudate lobe of the liver is separated from the right lobe by the inferior vena cava and from the left lobe by the fissure for the ligamentum venosum • The quadrate lobe of the liver is separated from the right lobe by the gallbladder and from the left lobe by the fissure for the ligamentum teres

Its function is to store and concentrate bile *** This is false; the gallbladder receives bile, concentrates it by absorbing water and salts, and stores it until delivered to the duodenum. Bile is produced and excreted by hepatocytes (liver cells), which are the most versatile cells in the body. Bile is secreted by the liver into the common hepatic duct. A short cystic duct from the gallbladder joins the common hepatic duct to form the common bile duct, which transports the bile inferiorly to the duodenum to help emulsify fat for digestion. Note: Kupffer cells line the sinusoids of the liver and function to filter bacteria and small foreign particles out of the blood. The liver is the heaviest and most active internal organ in the body. Many of the liver's functions are vital for life. Normally reddish brown in color, the liver lies under the cover and protection of the lower ribs on the right side of the abdomen. The liver has an upper (diaphragmatic) surface and a lower (visceral) surface; the two surfaces are separated at the front by a sharp inferior border. The liver is attached to the diaphragm by the falciform, triangular, and coronary ligaments. The liver is also joined to the stomach and duodenum by the gastrohepatic and hepatoduodenal ligaments respectively. The visceral surface of the liver is in contact with the gallbladder, the right kidney, part of the duodenum, the esophagus, the stomach, and the hepatic flexure of the colon. The porta hepatis -- the point where vessels and ducts enter and exit the liver -- lies on the ventral surface. The liver is divided into right, left, caudate, and quadrate lobes. The quadrate and caudate lobes are functionally part of the left lobe, although they are separated from it by a fissure on the visceral side and by the falciform ligament on the diaphragmatic side. The liver receives blood from two sources: the hepatic artery, which supplies the liver with oxygenated blood from the aorta, and the hepatic portal vein, which carries the products of digestion to the liver for processing. This blood eventually drains via the hepatic veins into the inferior vena cava, which transports the blood to the heart. Remember: The liver has digestive, metabolic, and regulatory functions; its chief digestive function is producing bile, which acts as a fat emulsifier in the small intestine.

is a tumor involving the vestibulocochlear nerve as it exits the cranial cavity. Because this tumor compresses surrounding structures or invades nearby tissues, in addition to hearing loss and equilibrium problems, a patient would most likely also demonstrate ipsilateral (same-sided) facial paralysis

Jugular foramen

All of the following organs are intraperitoneal (peritonealized organs having a Imesentery) EXCEPT one. Which one is the EXCEPTION? • Stomach • Jejunum • Ileum • Transverse colon • Kidneys • Liver • Gallbladder

Kidneys Abdominal cavity: the major part of the abdominopelvic cavity, bounded by the thoracic diaphragm and the pelvic inlet. The abdominal cavity includes both the peritoneal cavity and the retroperitoneal space. • Peritoneal cavity: that part of the abdomen surrounded by peritoneum. This is a potential space be-tween the parietal and visceral layers of peritoneum • Retroperitoneal space: the area behind (posterior to) the peritoneum. Retroperitoneal organs are located in this space Abdominal contents: • Peritoneum: a thin, serous membrane lining the walls of the abdominal and pelvic cavities and clothing the abdominal and pelvic viscera. The peritoneum can be regarded as a "balloon" into which organs are pressed into from the outside. The peritoneum has visceral and parietal layers, just like the pleural cavity • Parietal peritoneum: lines the walls of the abdominal and pelvic cavities • Visceral peritoneum: covers the organs *** The potential space between the two layers, which is in effect the inside space of the balloon, is called the peritoneal cavity. The peritoneal cavity can be divided into two parts: • Greater sac: is the main component of the peritoneal cavity and extends from the diaphragm down to the pelvis • Lesser sac: is smaller and lies behind the stomach *** The two sacs are in free communication with one another through an oval window called the opening of the lesser sac, or the epiploic foramen The terms intraperitoneal and retroperitoneal are used to describe the relationship of various organs to the peritoneal covering. An organ is said to be intraperitoneal when it is almost totally covered with visceral peritoneum. The following organs are considered to be intraperitoneal: the stomach, jejunum, ileum, spleen, transverse colon, liver, and gallbladder. Retroperitoneal organs are those that lie behind the peritoneum and are only partially covered with visceral peritoneum. The following organs or struc¬tures are considered to be retroperitoneal: the aorta, inferior versa cava, kidneys, adrenal glands, pan¬creas, ureters, and the ascending and descending parts of the colon. Note: Mesenteries are two-layered folds of peritoneum connecting parts of the intestines to the poste¬rior abdominal wall. These folds permit blood, lymph vessels, and nerves to reach the viscera.

The abdominal aorta terminates by dividing into the common iliac arteries and the middle sacral artery at what vertebral level?

L4

Most precisely, osteocytes are located in these spaces:

Lacunae: There are two types of bone tissue: compact and spongy. The names imply that the two types of bone tissue differ in density, or how tightly the tissue is packed together. There are three types of cells that contribute to bone homeostasis. Osteoblasts are bone-forming cells, osteoclasts resorb or break down bone, and osteocytes are mature bone cells. An equilibrium between osteoblasts and osteoclasts maintains bone tissue.

A collision during a basketball game left the point guard seeing double. The on-court physician determined that the paper-thin wall that holds up the eye had collapsed and the right eye now sat lower than it should have, thus causing the diplopia. Name the projection of the ethmoid bone that collapsed:

Lamina Papyracea

Peristalsis for what organ is controlled by taeniae coli? • Esophagus • Stomach • Large intestine • Small intestine

Large intestine Unlike those of the rest of the GI tract, longitudinal muscles do not form a continuous layer around the large intestine. Instead, three bands of longitudinal muscle, called taeniae con, run the length of the colon. Contractions gather the colon into bands (haustra), giving the colon its "puckered" appearance. The major function of the large intestine (also called the colon) is the removal of water from the material (chyme) entering it. Water is removed by absorption. Unlike the small intestine, the large intestine does not secrete enzymes into its lumen. Histologic characteristics: • Epithelium: simple columnar with microvillus border to increase surface area for absorption of water from the lumen. Mucus secreted by goblet cells lubricates dehydrating fecal mass. Intestinal glands (crypts of Lieberkuhn) invade lamina propria. The epithelium lacks villi. • Muscularis externa: inner circle consisting of a smooth muscle layer. Contains the three bands of longitudinal muscle, called taeniae coli, for peristalsis. Important: The vagus nerve supplies parasympathetic fibers to the ascending and transverse colons, while the descending and sigmoid colon along with the rectum and anus are supplied by the pelvic splanchnic nerves.

Lateral masses

Lateral masses (right and left) project downward from the cribriform plate. They contain the ethmoid sinuses and the orbital plate of the ethmoid bone (lamina papyracea). The lamina papyracea forms the paper-thin medial wall of the orbit. The superior and middle nasal conchae are scroll-like projections that extend medially from the lateral masses into the nasal cavity.Each ethmoidal sinus is divided into anterior, middle, and posterior ethmoidal air cells. Note: The superior wall or roof of the orbit is formed almost completely by the orbital plate of the frontal bone. Posteriorly, the superior wall is formed by the lesser wing of the sphenoid bone.

Which of the following ascending tracts of the spinal cord function to carry pain and temperature sensory information to the thalamus? • Lateral spinothalamic tract • Anterior spinothalamic tract • Fasciculi gracilis • Cuneatus • Spinocerebellar tract

Lateral spinothalamic tract The white matter of the spinal cord contains tracts that travel up and down the cord. Many of these tracts travel to and from the brain to provide sensory input to the brain, or bring motor stimuli from the brain to control effectors. Ascending tracts, those that travel toward the brain are sensory, descending tracts are motor. Note: For most tracts, the name will indicate if it is a motor or sensory tract. Most sen-sory tracts names begin with spino, indicating origin in the spinal cord, and their names end with the part of the brain where the tract leads. For example, the spinothalamic tract travels from the spinal cord to the thalamus. Tracts whose names begin with a part of the brain are motor. For example, the corticospinal tract begins with fibers leaving the cere¬bral cortex and travels down toward motor neurons in the cord.

Splenic artery -- to the spleen

Left gastroepiploic: arises from splenic artery at the hilum of the spleen to supply the greater curvature of stomach. Short gastrics: arise from the splenic artery at the hilum of the spleen to supply the fundus of stomach. Left gastric artery -- arises from the celiac artery to supply the lesser curvature of stomach and the lower third of the esophagus.

A patient comes to the emergency room after boxing practice. He was hit with an uppercut and heard a crack in his jaw joint. A CT scan shows a condylar fracture with damage to the articular disc. When the patient attempts protrusion, the mandible markedly deviates to the left. Which muscle is unable to contract? • Left lateral pterygoid • Right lateral pterygoid • Temporalis muscle • Buccinator

Left lateral pterygoid The right and left pterygoids acting together are the prime protractors of the mandible. When one muscle is not functioning properly, the contralateral muscle's action is unop-posed. The lack of the left lateral pterygoid trying to push the mandible to the right allows the right muscle to move the mandible to the left. With this injury, the mandible deviates toward the affected side. Similarly, because the muscle's insertion is disrupted (disconnected from the body of the mandible) in the case of a condylar fracture, the mandible will also deviate toward the affected side. The muscle is intact and can move the condyle when it contracts but not the body of the mandible because of the fracture. The unopposed right lateral pterygoid then remains capable of displacing the mandible to the left. Important: In addition to opening and protruding, the lateral pterygoids move the mandible from side to side. For right lateral excursive movements, the left lateral pterygoid muscle is the prime mover and vice versa. Note: With a condylar neck fracture, muscle contractions might result in displacement of the injured condyle into the infratemporal fossa

A 34-year-old female patient complains to her physician of hoarseness. The physician notes drastically enlarged lymph nodes in the aorticopulmonary window and suspects involvement of the recurrent laryngeal nerve. The path of the recurrent laryngeal differs on the left and right sides of the body. Which one (right or left) loops posteriorly around the aortic arch and ascends through the mediastinum to enter the groove between the esophagus and trache, • Right recurrent laryngeal nerve • Left recurrent laryngeal nerve

Left recurrent laryngeal nerve *** The left vagus gives rise to the left recurrent laryngeal nerve. *** The right recurrent laryngeal nerve splits from the right vagus before entering the superior mediastinum at the level of the right subclavian artery. The nerve hooks posteriorly around the subclavian artery and also ascends in the groove between the esophagus and trachea. Both recurrent laryngeal nerves pass deep to the lower margin of the inferior constrictor muscle to innervate the intrinsic muscles of the larynx responsible for controlling the movements of the vocal folds. The right recurrent laryngeal nerve innervates: • All of the muscles of the larynx, except the cricothyroid, which is supplied by the external laryngeal branch of the superior laryngeal nerve • The mucous membrane of the larynx below the vocal folds • The mucous membrane of the upper part of the trachea Note: This nerve comes in contact with the thyroid gland and comes into close relationship with the inferior thyroid artery The left recurrent laryngeal nerve innervates: • The same muscles and mucous membranes as the right recurrent laryngeal, except on the left side Remember: A few cardiac branches arise from the vagus and enter the cardiac plexus. These are preganglionic parasympathetic nerves that synapse with postganglionic parasympathetic nerves in the heart. They innervate the heart muscle and conducting system (SA node, etc.).

One method of the inferior alveolar nerve block, where the target is the mandibular foramen, encourages removal of the needle about halfway and deposition of approximately one-third of a carpule of anesthetic. This method is meant to anesthetize the nerve, which carries general sensation from the anterior two-thirds of the tongue. This nerve is the: • Hypoglossal nerve (CN X11) • Chorda tympani • Recurrent laryngeal nerve • Lingual nerve • Glossopharyngeal nerve (CN IX)

Lingual nerve The lingual nerve is a branch of the mandibular division (V-3) of the trigeminal nerve. It supplies general sensation for the anterior two-thirds of the tongue, the floor of the mouth, and mandibular lingual gingiva. Note: The submandibular duct has an intimate relation with the lingual nerve, which crosses it twice. The lingual nerve descends deep to the lateral pterygoid muscle, where the nerve is joined by the chorda tympani (branch of the facial nerve), which conveys the preganglionic parasympathetic fibers to the submandibular ganglion and taste fibers from the anterior two-thirds of the tongue. Important: If you cut the lingual nerve after its junction with the chord tympani, the tongue would have a loss of taste and tactile sense to the anterior two-thirds. 1. The chorda tympani emerges from a small canal in the posterior wall of the Notes tympanic cavity (petrotympanic fissure) after crossing the medial surface of the tympanic membrane. It joins the lingual nerve in the infratemporal fossa. 2. The chorda tympani nerve conveys general visceral efferent fibers (motor fibers) of the parasympathetic division of the autonomic nervous system. It carries special visceral afferent fibers for taste. 3. Parasympathetic nerves are general visceral efferent fibers.

Innervation: Serratus anterior Pectoralis minor Subclavius Trapezius Levator scapulae Rhomboid major Rhomboid minor

Long thoracic nerve, which arises from roots C5, 6, and 7 of the brachial plexus Medial pectoral nerve from medial cord of brachial plexus Nerve to the subclavius from the upper trunk of the brachial plexus Motor fibers from the spinal part of the accessory nerve and sensory fibers from the third and fourth cervical nerves Third and fourth cervical nerves and from the dorsal scapular nerve (C5) Dorsal scapular nerve (C5) Dorsal scapular nerve (C5)

Muscles of the Anterior Abdominal Wall Innervation: External oblique Internal oblique Transversus Rectus abdominis Pyramidalis (if present)

Lower six thoracic nerves and iliohypogastric and ilioinguinal nerves (LI) Same as above 1 Same as above 1 Lower six thoracic nerves Twelfth thoracic nerve

Kupffer cells in the liver are a specialized type of: • Basophil • Plasma cell • Mast cell • Macrophage

Macrophage A macrophage is any phagocytic cell derived from a monocyte (a type of blood cell), including macrophages of the liver (Kupffer cell), spleen, and loose connective tissue (histiocyte).

All muscles of mastication are innervated by the: • Ophthalmic division (V-/) of trigeminal nerve • Maxillary division (V-2) of trigeminal nerve • Mandibular division (V-3) of trigeminal nerve • Facial nerve (VII)

Mandibular division (V-3) of trigeminal nerve Mastication is defined as the physical process of chewing food in preparation for swal-lowing and ultimately digestion. Four pairs of muscles in the mandible make chewing possible. These muscles can be grouped into two different functions. The first group includes three pairs of muscles that elevate the mandible to close the mouth. The second group includes one pair of muscles that works to depress the mandible (drop the jaw), translate the jaw from side to side, and protrude the mandible forward. All are innervated by the mandibular division of the trigeminal nerve (V-3) -- see note below They receive blood from the pterygoid portion of the maxillary artery. Remember: 1. The masseter, temporalis, and medial pterygoid -- close the mouth (elevate the mandible) and hence account for the strength of the bite. 2. The lateral pterygoid -- opens, shifts (from side to side), and protrudes the mouth (or mandible). Note: There is one motor nucleus, a special visceral efferent (SVE) nucleus, associated with the trigeminal nerve. It innervates the muscles of the first branchial arch, which consists mostly of the muscles of mastication. They also include the tensor tympani and several other small muscles. The nucleus is located in the mid pons at the level of attach¬ment of the trigeminal nerve to the brainstem. Fibers of the trigeminal motor nucleus emerge as a separate motor root.

All of the following nerves are embedded in the lateral wall of the cavernous sinuses EXCEPT one. Which one is the EXCEPTION? • Trochlear nerve (CN IV) • Ophthalmic nerve (CN V-1) • Oculomotor nerve (CN III) • Maxillary nerve (CN V-2) • Mandibular nerve (CN V-3)

Mandibular nerve (CN V-3) The two cavernous sinuses are large veins lying within the skull cavity, immediately behind each eye socket and on either side of the pituitary gland. They connect with the veins of the face and those of the brain. These sinuses empty by way of the superior petrosal sinuses into the transverse sinuses that continue as the sigmoid sinuses. The sigmoid sinuses end at the jugular foramen by becoming the internal jugular veins. These sinuses are also emptied by the inferior petrosal sinuses that drain into the internal jugular veins. Because the veins of the head do not have valves, blood from the cavernous sinuses can also drain anteriorly into the ophthalmic veins. The cavernous sinus is an important structure because of its location and its contents. This sinus carries in its lateral wall the third cranial (oculomotor) nerve, the fourth cranial (trochlear) nerve, and parts 1 (the ophthalmic nerve) and 2 (the maxillary nerve) of the fifth cranial (trigeminal) nerve. Remember: The internal carotid artery and the abducens nerve (CN VI) pass through the sinus. 1. A cavernous sinus thrombosis is a blood clot within the cavernous sinus. iNotes' This clot causes the cavernous sinus syndrome. 2. The cavernous sinus syndrome is characterized by edema of the eyelids and the conjunctivae of the eyes and paralysis of the cranial nerves that course through the cavernous sinus. 3. The orbital cavity is drained by the superior and inferior ophthalmic veins. The superior ophthalmic vein communicates in front with the facial vein. The inferior ophthalmic vein communicates through the inferior orbital fissure with the pterygoid venous plexus. Both veins pass backward through the superior orbital fissure and drain into the cavernous sinus.

Apical abscesses of which teeth have a marked tendency to produce cervical spread of infection most rapidly? I • Mandibular central and lateral incisors • Mandibular canine and first premolar • Maxillary first and second molars • Mandibular second and third molars

Mandibular second and third molars Certain anatomic features determine to a large extent the actual direction that infection may take. The attachment of muscles may determine the route that an infection will take, channeling the infection into certain tissue spaces. (See chart 294)

When using a high-speed handpiece to remove caries from a tooth, the dentist must drill past the enamel into dentin. The first layer of dentin (at the DEJ) is called: • Intratubular dentin • Intertubular dentin • Mantle dentin • Circumpulpal dentin • Interglobular dentin

Mantle dentin Mantle dentin is the first predentin that forms and matures within the tooth. Mantle dentin shows a difference in the direction of the mineralized collagen fibers compared with the rest of dentin, with the fibers perpendicular to the DEJ. Mantle dentin also has more peritubular dentin than the inner portions of the dentin and thus has higher levels of mineralization. The layer of dentin around the outer pulpal wall is called circumpulpal dentin. All circumpulpal dentin is formed and matures after mantle dentin. The collagen fibers of circumpulpal dentin are mainly parallel to the DEJ compared with those of mantle dentin. Circumpulpal dentin makes up the bulk of the dentin in a tooth Remember: Each dentinal tubule contains the cytoplasmic cell process (Tomes' fiber) of an odontoblast. Important: Odontoblasts secrete the organic components of the dentin matrix. The fibrous matrix is mostly type I collagen. Note: Dead tracts consist of groups of empty tubules due to the death of the odontoblasts whose processes formerly filled the tubules. These tracts have been attributed to the aging process of the dentinal tissue. They may also be caused by caries, erosion, cavity preparation, or odontoblastic crowding.

Origin Insertion Action Innervation Sternocleidomastoid Digastric Posterior belly Anterior belly Mylohyoid Stylohyoid Geniohyoid Stemohyoid Sternothyroid Thyrohyoid Omohyoid Inferior belly Superior belly

Manubrium stemi and medial third of clavicle Mastoid process of temporal bone Body of mandible Mylohyoid line of body of mandible Styloid process of temporal bone Inferior mental spine of mandible Manubrium stemi and clavicle Manubrium sterni Oblique line on lamina of thyroid cartilage Upper margin of scap- ula Lower border of body of hyoid bone Mastoid process of temporal bone and occipital bone Intermediate tendon is held to hyoid bone by fascial sling Body of hyoid bone and fibrous raphe Body of hyoid bone Body of hyoid bone Body of the hyoid bone Oblique line on lamina of thyroid cartilage Lower border of body of hyoid bone Intermediate tendon is held to clavicle and first rib by fascial sling Two muscles acting together extend head and flex neck; one muscle rotates head to opposite side Depresses the mandi- ble or elevates the hyoid bone Elevates floor of mouth and hyoid bone or depresses mandible Elevates hyoid bone Elevates hyoid bone or depresses mandible Depresses the hyoid bone Depresses the larynx Depresses hyoid bone or elevates larynx Depresses the hyoid bone Spinal part of accessory nerve C2 and 3 Facial nerve Nerve to mylohyoid Trigeminal (V-3) nerve Facial nerve First cervical nerve Ansa cervicalis (CI, 2, and 3) Ansa cervicalis (CI, 2, and 3) First cervical nerve Ansa cervicalis (Cl, 2 and 3)

On the playground at recess, a young girl is stung by a bee and immediately breaks out in hives and starts gasping for air. The teacher grabs an epinephrine autoinjector from the first aid kit and is able to save the girl. What cells, when bound by IgE, are responsible for this anaphylactic reaction? • Mast cells • Macrophages • Platelets • Kupffer cells

Mast cells Mast cells are large cells with coarse metachromatic granules containing heparin (anticoagulant), histamine (vasodilator), and other substances (i.e., chemotactic factors, such as eosinophil chemotactic factor of anaphylaxis and neutrophil chemotactic factor). They occur in most loose connective tissue, especially along the path of blood vessels. These cells act as mediators of inflammation on contact with antigen. Note: Normally, mast cells are not found in circulation. Both mast cells and basophils liberate heparin into the blood. Heparin can prevent blood coagulation as well as speed the removal of fat particles from the blood after a fatty meal. They both also release histamine as well as smaller quantities of bradykinin and serotonin. Note: It is mainly the mast cells in inflamed tissues that release these substances during inflammation. The mast cells and basophils play an exceedingly important role in some types of allergic reactions because the type of antibody that causes allergic reactions (the IgE type) has a special propensity to become attached to mast cells and basophils. The reaction between antigen and antibody causes the mast cell or basophil to rupture and release exceedingly large quantities of histamine, bradykinin, serotonin, heparin, SRS-A (slow-reacting substance of anaphylaxis), and a number of lysosomal enzymes. This, in turn, causes local vascular and tissue reactions that cause many, if not most, of the allergic manifestations.

A young patient arrives in the physician's office with unexplained symptoms for a long time. The patient has had bloody nasal discharge and painful oral lesions. A chest x-ray reveals "coin lesions", and labs reveal kidney failure. Ultimately, the isolation of the ANCAs - IgG antibodies - yield a diagnosis of Wegener's granulomatosis. The dentist who referred this patient to the physician made a note of the necrotizing oral lesion that had perforated the hard palate into the nasal cavity. The roof of the oral cavity is formed by the:

Maxilla and palatine bones: Specifically, the palatine processes of the maxilla and the horizontal plates of the palatine bones. The structure formed by this union is the hard palate. The anterior two-thirds of the hard palate is formed by the palatine processes of the maxilla, and the posterior one-third is formed by the horizontal plates of the palatine bones. The hard palate forms not only the roof of the oral cavity proper but also the floor of the nasal cavity. It is covered with a mucous membrane and beneath the mucosa are palatal salivary glands. The greater (anterior) palatine vein, artery, and nerve travel along the maxillary alveolar processes anteriorly where they join the nasopalatine nerves and sphenopalatine artery and vein, exiting the nasal cavity from the incisive foramen.

Which division of the trigeminal nerve exits the cranial cavity through the foramen rotundum and provides sensory innervation to the midface ----_. (lower eyelid to the upper cheek), palate, and paranasal sinuses? • Ophthalmic division (V-/) • Maxillary division (V-2) • Mandibular division (V-3)

Maxillary division (V.2) The ophthalmic division (V-/) enters the orbit through the superior orbital fissure and provides sensory innervation to the eyeball, tip of the nose, skin over the upper and lower eyelid, and skin of the face above the eye. Branches include the lacrimal, frontal, nasociliary, supraorbital, supratrochlear, infratrochlear, and external nasal nerves. Note: During a sinus attack, painful sensation from the ethmoid cells is carried in the nasociliary nerve. The maxillary division (V-2) passes through the foramen rotundum and provides sensory innervation to the midface (below the eye and above the upper lip), palate, paranasal sinuses, and the maxillary teeth. Note: The tickling sensation felt in the nasal cavity just prior to a sneeze is carried by the maxillary division of trigeminal. Branches include the infraorbital, zygomaticofacial, and zygomaticotemporal nerves. Sensory innervation of mandibular division (V-3) is to the skin of the cheek, the skin of the mandible, and the lower lip and side of the head. Sensory innervation also includes the TMJ, mandibular teeth, the mucous membranes of the cheek, the floor of the mouth, and the anterior part of the tongue. Branches include the mental, buccal, and auriculotemporal nerves. Important: The trigeminal nerve contains no parasympathetic component at its origin. The nerves branches are used by the oculomotor, facial, and glossopharyngeal nerves to distribute their preganglionic parasympathetics to the parasympathetic head ganglia.

During the fourth week of prenatal development, the upper lip is formed when each fuses with each as a result of the ---...- underlying growth of the mesenchyme. I • Frontonasal process; lateral nasal process • Maxillary process; medial nasal process • Lateral nasal process; medial nasal process • Maxillary process; lateral nasal process

Maxillary process; medial nasal process Thus, the maxillary processes contribute to the sides of the upper lip, and the two medial nasal processes contribute to the middle of the upper lip. Fusion of these processes to form the upper lip is completed during the sixth week of prenatal development, when the grooves between the processes are obliterated. The maxillary processes on each side of the developing face partially fuse with the mandibular arch to form the labial commissures, or corners, of the mouth. After formation of the stomodeum (the primitive mouth) but still within the fourth week, two bulges of tissue appear inferior to the primitive mouth, the two large mandibular processes of the first branchial arch. The mandible forms as a result of the fusion of the right and left mandibular processes. The mandible is the first portion of the face to form after the creation of the stomodeum. Note: The mandible (except for the condyles) and the maxilla are mostly formed by intramem¬branous ossification. The maxilla is formed primarily by merging of the two smaller maxillary processes of the first branchial arch. These maxillary processes also form the upper cheek regions and most of the upper lip. During the fourth week, the frontonasal process (prominence) also forms. It is a bulge of tissue in the upper facial area, at the most cephalic end of the embryo, and is the cranial boundary of the stomodeum. In the future, the frontonasal process gives rise to the upper face, which includes the forehead, bridge of nose, primary palate, nasal septum, and all structures related to the medial nasal processes. The nasal placodes form in the anterior portion of the frontonasal process, just superior to the sto¬modeum, during the fourth week. These two buttonlike structures form as bilateral ectodermal thick- enings that later develop into olfactory cells for the sensation of smell. The middle portion of the tissue growing around the nasal placodes appears as two crescent-shaped swellings and are called the medial nasal processes, which fuse to form the middle portion of the nose from the root to the apex and the center portion of the upper lip and also the philtrum region. On the outer portion of the nasal placodes, there are also two other crescent-shaped swellings, the lateral nasal processes, which will form the alae, or sides of the nose. Fusion of the lateral nasal, maxillary, and medial nasal processes forms the nares, or nostrils. Note: Lateral clefting of the lip results from the failure of the maxil¬lary and medial nasal processes to fuse.

The pterygoid venous plexus is a venous network associated with the pterygoid muscles. It receives veins that correspond to branches of the maxillary artery, and the network's posterior end is drained by the: • Facial vein • Maxillary vein • Brachiocephalic vein • Retromandibular vein

Maxillary vein Veins corresponding to all branches of the maxillary artery drain into the pterygoid plexus of wins. This plexus occupies the infratemp ora... f ossa and is situated between the temporalis and lateral pterygoid muscles. It is a venous network associated with the pterygoid muscles. Its posterior end is drained by the maxillary vein. The network communicates with the facial vein through the deep facial vein. Important: The following venous channels have direct connections with the pterygoid venous plexus -- the maxillary, deep facial, infraorbital, and posterior superior alveolar veins. The maxillary vein is a short vessel that drains the posterior end of the pterygoid venous plexus. This vein runs backward with the maxillary artery on the medial side of the neck of the mandible and joins the superficial temporal vein within the parotid gland, to form the retromandibular vein. The facial vein is formed at the medial angle of the eye by union of the supraorbital and supratrochlear veins. This vein anastomoses with the retromandibular vein (anterior branch) below the border of the mandible. The facial vein ends by draining into the main venous structure in the neck, the internal jugular vein. Remember: The internal jugular vein descends through the neck within the carotid sheath and unites behind the sternoclavicular joint with the subclavian vein to form the brachiocephalic vein. The brachiocephalic veins (right and left) unite in the superior mediastinum to form the superior vena cava, which returns blood to the right atrium of the heart.

Principal Kinds of Tissues: Description and Function, Types/Examples Epithelial tissues Connective tissues Muscular tissues Nervous tissues

May be one (simple) or several (stratified) layers thick; lower surface bound to a supportive basement membrane; mitotically active tissue; avascular; cover the surface of the body and line the various body cavities, ducts, and vessels Highly vascular (except for cartilage); contain considerable intercellular matrix; mitotically active tissue; used for support (bones and cartilage), for attachment of other tissues (tendons, ligaments, and fasciae), or for other specialized functions (such as blood) Limited mitotic activity; composed of specialized cells that are capable of contracting and thereby decreasing in length; these tissues move the skeleton, propel the blood throughout the body, and aid in digestion by moving food through the digestive tract Limited mitotic activity; transmit messages throughout the body Two types: • Covering and lining epithelium covers the outside of the body and lines internal organs • Glandular epithelium Tendons and ligaments; cartilage and bone, adipose tissue, blood Types of connective tissue proper: • Areolar • Dense (regular) • Elastic • Reticular • Adipose Three types: • Smooth • Cardiac • Skeletal Form brain, spinal cord, and nerve, consist largely of cells (neurons) with long protoplasmic extensions.

Nerve supply: Pectoralis major Pectoralis minor Latissimus dorsi Deltoid Teres major Teres minor

Medial and lateral pectoral nerves from medial and lateral cords of brachial plexus Medial pectoral nerve from medial cord of brachial plexus Thoracodorsal nerve from posterior cord of brachial plexus Axillary nerve (C5 and C6) Lower subscapular nerve from posterior cord of brachial plexus Branch of axillary nerve

The extended course of the abducens nerve from the brainstem to the eye makes it vulnerable to injury. In blunt force trauma to the head, an individual's petrous temporal bone is fractured, leading to the injury of the right abducens nerve. Which of the following would be a sign of that injury? • Right ptosis • Loss of light reflexes on the right side • Inability to adduct the right eye • Medial deviation of the right eye • Loss of corneal reflex on the right side

Medial deviation of the right eye Remember: The abducens (CN VI) nerve innervates the lateral rectus muscle of the eye. The lateral rectus muscle is responsible for lateral gaze (its contraction causes the eye to be abducted). A lesion of this nerve results in medial strabismus (cross-eyed) and diplopia (double vision).

A nervous dental student is performing local anesthesia for the first time on one of his peers. He has read his notes meticulously but is still very shaky. After the inferior alveolar nerve injection, he gains confidence and performs the rest of the injections without a hitch. The next day, the classmate whom he performed injections on is complaining of jaw pain and the inability to open his mouth. Which muscle did the nervous student penetrate during the IAN injection, which, along with the masseter forms a sling around the mandible? • Temporalis • Medial pterygoid • Lateral pterygoid • Buccinator • Posterior belly of the digastric

Medial pterygoid The angle of the mandible rests in this sling. The medial pterygoid muscle arises from the medial surface of the lateral pterygoid plate and inserts on the medial surface of the angle and ramus of the mandible. Important: The medial pterygoid, masseter, and temporalis (mainly anterior portion) elevate the mandible during jaw closing (biting and chewing). 1. The superior origin of the lateral pterygoid muscle is from the infratemporal Notes(' crest of the greater wing of the sphenoid bone, and the inferior origin is from the lateral surface of the lateral pterygoid plate of sphenoid bone. Both heads insert at the articular disc of TMJ and neck of mandibular condyle. Remember: • The mandible is protruded by both the action of both lateral pterygoid muscles • One muscle causes lateral deviation of the mandible (shifts mandible to opposite side) 2. The masseter muscle originates from the lower border and medial surface of the zygomatic arch. The muscles fibers run downward and backward to be attached to the lateral aspect of the ramus of the mandible. 3. All of the muscles of mastication are innervated by the mandibular division of the trigeminal nerve.

Which muscles elevate the mandible and hence account for the strength of the bite? • Medial pterygoid, digastric -- both anterior and posterior belly, and lateral pterygoid • Digastric -- both anterior and posterior belly, and lateral pterygoid • Medial pterygoid, temporalis, and masseter • Digastric -- both anterior and posterior belly, temporalis, and masseter

Medial pterygoid, temporalis, and masseter Important: The muscles of mastication are innervated by the trigeminal nerve (specif-ically, the mandibular division -- V3).

The middle pharyngeal constrictor muscle attaches anteriorly to the hyoid bone and the stylohyoid ligament. Like the other pharyngeal constrictor muscles, this muscle inserts posteriorly into the: • Fibers of the buccinator muscle • Posterior border of the thyroid cartilage • Median pharyngeal raphe • Palatopharyngeus muscle

Median pharyngeal raphe The constrictor muscles of the pharynx are involved in the digestive process, being responsible for moving food down to the esophagus. The stylopharyngeus, along with the deeper muscles of the palatopharyngeus and the salpingopharyngeus, are involved in elevating the larynx. 1. All of the circular muscles are innervated by the vagus nerve via the pharyn¬= Notes geal plexus. 2. The stylopharyngeus, palatopharyngeus, and salpingopharyngeus are all lon¬gitudinal muscles of the pharynx.

A patient in the dental clinic hates getting alginate impressions taken on him because he is a "gagger." Which of the following is the most inferior portion of the brainstem and controls reflex activities such as coughing, gagging, and vomiting? • Midbrain • Pons • Cerebrum • Medulla

Medulla The brain stem, which is continuous with the spinal cord below, consists of the mid-brain, pons, and medulla. Passing through the brain stem are ascending pathways car¬rying sensory information from the spinal cord to the brain, and descending pathways, carrying motor commands down to the spinal cord. Centers in the brain stem regulate many vital functions, including heartbeat, respiration, and blood pressure. • The midbrain connects dorsally with the cerebellum. The midbrain relays motor sig¬nals from the cerebral cortex to the pons, and sensory transmission in the opposite di¬rection, from the spinal cord to the thalamus. The oculomotor (CN III) and trochlear (CN IV) nerves arise in the midbrain. The substantia nigra in the midbrain helps to control movement. Lesions of the substantia cause Parkinson's disease. • The pons lies below the midbrain and connects the cerebellum with the cerebrum. The pons also links the midbrain to the medulla oblongata. It is involved with motor activ¬ity of the body and organs. In addition to housing one of the brain's respiratory centers, the pons acts as a pathway for conduction tracts between brain centers and the spinal cord, and serves as the exit point for cranial nerves V, VI, VII, and VIII. • The medulla oblongata is the most inferior portion of the brain stem and is a small, cone-shaped structure that joins the spinal cord at the level of the foramen magnum. The medulla oblongata functions primarily as a relay station for the crossing of motor tracts between the spinal cord and the brain. The medulla oblongata also contains mecha¬nisms for controlling reflex activities such as coughing, gagging, swallowing, and vom¬iting. It's the site of origin for cranial nerves IX, X, XI, and XII. The medulla oblongata also contains a central core of gray matter called the reticular formation. This area is involved in regulating sleep and arousal, and in pain perception, and includes vital cen¬ters that regulate breathing and heart activity.

A specialized type of cell division that occurs in the formation of gametes such as egg and sperm is called: • Binary fusion • Conjugation • Mitosis • Meiosis

Meiosis Although meiosis appears much more complicated than mitosis, meiosis is really just two divisions in sequence, each one of which has strong similarities to mitosis. Meiosis I, the first of the two divisions, is often called reduction division, since it is here that the chromosome complement is reduced from 2N (diploid) to IN (haploid). Interphase in meiosis is identical to interphase in mitosis and there is no way, by simply observing the cell, to determine what type of division the cell will undergo when it does divide. Meiotic division will occur only in cells associated with male or female sex organs. Prophase I is virtually identical to prophase in mitosis, involving the appearance of the chromosomes, the development of the spindle apparatus, and the breakdown of the nuclear membrane (envelope). Here is where the critical difference occurs between metaphase I in meiosis and metaphase in mitosis. In the latter, all the chromosomes line up on the metaphase plate in no particular order. In metaphase I, the chromosome pairs are aligned on either side of the metaphase plate. It is during this alignment that chromatid arms may overlap and temporarily fuse (chiasmata), resulting in crossovers. During anaphase I the spindle fibers contract, pulling the homologous pairs away from each other and toward each pole of the cell. A cleavage furrow typically forms at this point, followed by cytokinesis, but the nuclear membrane usually is not re-formed and the chromosomes do not disappear. At the end of telophase I, each daughter cell has a single set of chromosomes, half the total number in the original cell where the chromosomes were present in pairs. While the original cell was diploid, the daughter cells are now haploid. This is why meiosis I is often called reduction division. Meiosis II is quite simple in that it is simply a mitotic division of each of the haploid cells produced in meiosis I. There is no interphase between meiosis I and meiosis II. When meiosis H is complete, there will be a total of four daughter cells, each with half the total number of chromosomes as the original cell. In the case of male structures, all four cells will eventually develop into typical sperm cells. In the case of female structures, three of the cells will typically abort, leaving a single cell to develop into an egg cell that is usually much larger than a typical sperm cell.

What type of cell in the dental papilla adjacent to the inner enamel epithelium differentiates into odontoblasts? • Myoepithelial cell • Mesenchymal cell • Macroglia cell • Mast cell

Mesenchymal cell -- also called mesoblastic cells These cells have the potential to proliferate and differentiate into diverse types of cells (fibroblasts, chondroblasts, odontoblasts, and osteoblasts). Mesenchymal cells form a loosely woven tissue called mesenchyme or embryonic connective tissue. Important: The mesenchymal cells in the dental papilla adjacent to the inner enamel epithelium differentiate into odontoblasts, which produce predentin that calcifies to become dentin. Mesectoderm (also called ectomesenchyme) is that part of the mesenchyme derived from ectoderm, especially from the neural crest in the very young embryo. Neural crest cells give rise to spinal ganglia (dorsal root ganglia) and the ganglia of the autonomic nervous system. These cells also give rise to neurolemma cells (Schwann cells), cells of the meninges that cover the brain and spinal cord, pigment cells (melanocytes), chromaffin cells of the adrenal medulla, and several skeletal and muscular components of the head.

Liver spots are seen as a sign of aging and are actually lipofuscin granules preNs- ent in dermal cells. Lipofuscin is a yellow-brown pigment that is produced as a result of lysosomal digestion. What is the collective name given to lifeless substances, including lipofuscin granules, yolk, fat, and starch, that may be stored in various parts of the cytoplasm? • Protoplasm • Nucleoplasm • Ectoplasm • Metaplasm

Metaplasm -- sometimes called cytoplasmic inclusions Examples: • Glycogen: carbohydrate storage granules in liver and muscle cells. • Fat deposits • Pigment granules: deposits of colored substances. 1. Lipofuscin: yellowish-brown substance that increases in quantity as cells age. 2. Melanin: abundant in epidermis of the skin and retina. Protoplasm is a viscous, translucent, watery material that is the primary component of animal cells. It contains a large percentage of water, inorganic ions (potassium, calcium, magnesium, and sodium), and naturally occurring organic compounds (such as proteins, lipids, and carbohydrates). Nucleoplasm, the protoplasm of the cell nucleus, plays a part in reproduction. Cytoplasm, the protoplasm of the cell body that surrounds the nucleus, converts raw materials into energy. The cytoplasm is the site of most synthesizing activities and contains cytosol (a viscous, semitransparent fluid that is 70% to 90% water), organelles, and inclusions (metaplasm). A clear, thin film of protoplasm called the cell membrane always surrounds the cytoplasm. The outer part of the cytoplasm is called the ectoplasm.

Which branch of the maxillary artery runs through the foramen spinosum\ and is implicated in epidural hematomas?

Middle meningeal artery

Which organelle is known as the cell's "power plant" and is maternally transmitted? • Peroxisomes • Ribosomes • Centrosomes • Mitochondria

Mitochondria Mitochondria are thread-like structures within the cytoplasm that provide most of the body's ATP, which fuels many cellular activities.

A patient with a "heart-valve problem" comes into the dental clinic for periodontal therapy. She says that her old periodontist always gave her antibiotics before treatment, and insisting that the dentist hear the problem, she places the stethoscope in the left fifth intercostal space medial to the nipple line. Which heart valve is best heard over the apex of the heart? • Tricuspid valve • Mitral valve • Pulmonary valve • Aortic valve

Mitral valve (Bicuspid valve) The four valves of the heart are designed to allow one-way flow only of blood. Their function is to prevent backflow into the releasing chamber. The four heart valves work in pairs in tandem: • During ventricular systole, the ventricles of the heart contract, and the pulmonary and aortic valves open to allow blood to be pumped into the pulmonary and general circulatory systems, respectively, while the mitral and tricuspid valves remain closed. • During ventricular diastole, the aortic and pulmonary valves close, while the atri-oventricular valves (the mitral and tricuspid valves) open to allow blood to pass from the atria to the ventricles. 1. The atrioventricular valves -- the mitral and tricuspid valves -- separate the Notesgj atrium and ventricle on the left and right sides of the heart respectively. 2. The aortic and pulmonary valves are said to be semilunar valves, because each consists of three half-moon-shaped valve cusps that are attached to the in¬side wall of the aortic and pulmonary arteries. 3. The apex of the heart lies in the left fifth intercostal space medial to the nipple line, about 9 cm from the midline. This location is useful for determining the left border of the heart and for auscultation of the mitral (bicuspid) valve. 4. The tricuspid valve is best heard over the right half of the lower end of the body of the sternum. 5. The pulmonary valve is best heard over the second left intercostal space. 6. The aortic valve is best heard over the second right intercostal space.

Most bones are

Most bones are endochondral, meaning that they began as a hyaline cartilage model before they ossify. This takes place within hyaline cartilage. This type of ossification is principally responsible for the formation of short and long bones. Bone replaces cartilage (osteocytes replace chondrocytes). The bones of the extremities and those parts of the axial skeleton that bear weight (e.g., vertebrae) develop by endochondral ossification.

nerves of tongue

Motor innervation is from the hypoglossal nerve (CN XII). Sensory innervation - lingual (branch of trigeminal CN V-3) supplies the anterior two-thirds, glossopharyngeal (CNIA) supplies the posterior one-third (including vallate papillae), vagus (CN X) through the internal laryngeal nerve supplies the area near the epiglottis. Taste - facial (CN VII) via chorda tympani supplies the anterior two-thirds; glossopharyngeal (CN/A) supplies the posterior one-third.

A 50-year-old female was diagnosed with anaplastic thyroid cancer and underwent aggressive surgery to remove most of the thyroid. Unfortunately, the surgeon also excised the parathyroid glands. Which of the following could result from the excision of the parathyroid glands? • Strengthening of muscles • Weakening of bones • Muscle convulsions • Decalcification of bones

Muscle convulsions *** A deficiency of PTH can lead to tetany, muscle weakness due to a lack of available cal¬cium in the blood. The body's smallest known endocrine glands, the parathyroid glands are small, pea-like organs embedded beneath the posterior surface of the thyroid gland. Most people have four of them. Working together as a single gland, the parathyroid glands produce parathyroid hormone. Parathyroid hormone is the most important regulator of calcium and phosphorus concentration in extracellular fluid. It finds its major target cells in bone and kidney. These glands are es¬sential for life. Each parathyroid gland has a fibrous tissue capsule and two types of cells: • Chief cells - produce parathyroid hormone, which acts to raise the concentration of cal¬cium in the blood and reduce the concentration of phosphate ions • Oxyphil cells - function is undetermined They receive innervation from the postganglionic sympathetic fibers of the superior cervical ganglion. The superior pair receives its blood supply from the superior thyroid artery (from external carotid) and the inferior pair from the inferior thyroid artery (from thyrocervical trunk). Note: The thyrocervical trunk is short and thick and arises from the first portion of the sub¬clavian artery close to the medial border of the scalenus anterior. This trunk divides almost im¬mediately into the following three branches: inferior thyroid, suprascapular, and transverse cervical (or superficial cervical) arteries. 1. These glands develop from the third and fourth pharyngeal pouches. 2. The tiny pineal gland lies at the back of the third ventricle of the brain. This gland produces the hormone melatonin. This hormone is thought to play a number of roles in humans, including the regulation of the sleep-wake cycle, body temper¬ature regulation, and appetite.

The thyroid gland can be examined in which of the following triangles of the neck? • Submental • Glandular • Carotid • Submandibular (or digastric) • Muscular (or visceral)

Muscular (or visceral) Remember: The neck is arbitrarily subdivided into two triangles by the sternocleido-mastoid muscle: the anterior and posterior triangles. The anterior triangle is then sub¬divided into the submental, submandibular, muscular (or visceral), and the carotid triangles. The posterior triangle is then subdivided into the occipital and supraclavicu¬lar (omoclavicular) triangles. The largest of the endocrine glands, the thyroid gland consists of two lobes, the right and left, which are joined across by a thin band called the isthmus. The thyroid gland is an "H"-shaped structure located anterior to the upper part of the trachea near its junction with the larynx. Thyroid epithelial cells -- the cells responsible for synthesis of thyroid hormone -- are arranged in spheres called thyroid follicles. These follicles are filled with colloid. Colloid is composed of thyroglobulin and iodine and is the storage form of the thyroid hormones T3 and T4. Note: Thyroid hormone is composed of two different substances: thyroxine (also called T4, or tetraiodothyronine) and triiodothyronine (T3). Thyroid hormone has several functions, the main one being to determine the metabolic rate of body tissues. Important: The production of thyroid hormone is under the control of thyroid-stimu¬lating hormone (TSH), which is released from the pituitary gland. In addition to thyroid epithelial cells, the thyroid gland houses one other important en-docrine cell. Nestled in spaces between thyroid follicles are parafollicular or C cells, which secrete the hormone calcitonin. Calcitonin acts to reduce blood calcium, opposing the effects of parathyroid hormone (PTH). Note: The thyroglossal duct is a narrow canal that connects the thyroid gland to the tongue during development. This duct disappears soon after development of the gland. In the adult, the proximal end of the duct persists as the foramen cecum of the tongue.

A worker in the meat-processing industry comes down with an illness, presenting with symptoms of fever, headache, and sore throat. A few days later, he feels chest pain and has pink, frothy sputum. His physician states that the worker has a viral infection caused by coxsackie B. This patient has inflammation of which layer of the heart (the thickest and the workhorse)? • Epic ardium • Myocardium • Endocardium

Myocardium Layers of the heart: 1. Internal or endocardium -- Homologous with the tunica intima of blood vessels. Lines the surface of the heart chambers with a simple squamous endothelium and un-derlying loose connective tissue containing small blood vessels. 2. Myocardium -- Homologous with the tunica media of blood vessels. Forms the bulk of the heart mass and consists predominantly of cardiac muscle cells arranged in a spi¬ral configuration. This spiral arrangement allows the heart to "wring" the blood from the ventricles toward the aortic and pulmonary semilunar valves. 3. Pericardium -- is the set of membranes around the heart (it is actually composed of three layers of membranes). The innermost is the visceral pericardium, the middle is the parietal pericardium, and the outer one is the extra one, called the fibrous peri¬cardium. The inner two (visceral and parietal) are rather thin and delicate. The outer one, the fibrous pericardium, is tough. Important: The major sensory nerve to the pari¬etal pericardium is from branches of the phrenic nerve (C3-05). Important: The heart and its pericardium make up the contents of the middle medi-astinum. The left and right phrenic nerves and their adjacent arteries lie to the left and right of the pericardium and anterior to the roots of the lungs.

The nasal cavities are formed from which embryonic structure?

Nasal pits

In the ER, a car-accident victim who hit his face on the steering wheel arrives bleeding profusely from the mouth and nose. Upon examination, the physician discovers that along with avulsed teeth, his hard palate is fractured and the incisive foramen is obliterated. Which artery emerges from the incisive foramen?

Nasopalatine artery: In the pterygopalatine fossa, the maxillary artery gives rise to the descending palatine artery, which travels to the palate through the pterygopalatine canal, which then terminates in both the greater palatine artery and lesser palatine artery by way of the greater and lesser palatine formamina to supply the hard and soft palates, respectively.

As a general rule, parasympathetic preganglionic neurons synapse with postganglionic axons in ganglia: • Near the thoracolumbar region • At the cranial nerves • Near or within target organs • Of the paravertebral chain

Near or within target organs The autonomic nervous system runs bodily functions without our awareness or control. It is the motor system to visceral organs. It is divided into two systems: • Sympathetic (thoraco-lumbar) division: - "Fight, fright, or flight" - Derived from thoracic and lumbar spinal nerves (T1-L2) • Preganglionic neurons (myelinated): relatively short - Cell bodies are located in the intermediolateral gray column of thoracic and lumbar vertebrae - Preganglionic neurons exit ventral root -- into white ramus communications -- synapse with postganglionic axon in peripheral ganglion at the same level or another level - Neurotransmitter is acetylcholine • Postganglionic axons (unmyelinated): relatively long - Cell bodies in peripheral ganglia extend to visceral organs - Distribution is widespread - Neurotransmitter is norepinephrine • Parasympathetic (cranial-sacral) division: -"food or sex" - Derived from cranial and sacral nerves -- CN III, VII, IX, and X; S2-S4 • Preganglionic neurons (myelinated): relatively long - Synapse with postganglionic axons in ganglia close to organs - Neurotransmitter is acetylcholine • Postganglionic axons (unmyelinated): relatively short - Neurotransmitter is acetylcholine - Distribution is more specific and less diffuse than sympathetic Sympathetic vs. Parasympathetic • Most organs have dual innervation • In general, the actions of one system oppose those of the other • Both divisions are cooperative in salivary glands • Predominant tone is parasympathetic in most organs • Sympathetic tone exists solely in adrenal medulla, sweat glands, piloerector muscles of skin, and many blood vessels • Sympathetic distribution tends to be more diffuse whereas parasympathetic is more specific

Which of the following is the line found in all deciduous teeth and in the larger cusps of the permanent first molars that marks the division between enamel formed before birth and enamel formed after birth? lei • Hunter-Schreger bands • Lines of Retzius • Perikymata • Neonatal line

Neonatal line Enamel formation begins at the future cusp and spreads down the cusp slope. As the ameloblasts retreat in incremental steps, the ameloblasts create an artifact in the enamel called the lines of Retzius. Where these lines terminate at the tooth surface they create tiny valleys on the tooth surface that travel circumferentially around the crown known as perikymata or imbrication lines of Pickerill. One of the lines of Retzius is accentuated and is more obvious than the others. It is the neonatal line that marks the division between enamel formed before birth and that which is produced after birth -- this neonatal line is found in all deciduous teeth and in the larger cusps of the permanent first molars. • Enamel tufts are fan-shaped, hypocalcified structures of enamel rods that project from the dentinoenamel junction into the enamel proper. They are found in the inner one-third of enamel and represent areas of less mineralization. Enamel tufts are an anomaly of crystallization and seem to have no clinical importance. • Enamel spindles represent short dentinal tubules near the DEJ. They result from odontoblasts that crossed the basement membrane before it mineralized into the DEJ. These dentinal tubules become trapped during the apposition of enamel matrix, and enamel becomes mineralized around them. They may serve as pain receptors. • Enamel lamellae are partially calcified vertical defects in the enamel resembling cracks or fractures that traverse the entire length of the crown from the surface to the DEJ. They are narrower and longer than enamel tufts. Enamel lamellae are an anomaly of crystallization and seem to have no clinical importance. The term Hunter-Schreger bands refers to the alternating light and dark lines seen in dental enamel that begin at the DEJ and end before they reach the enamel surface. They represent areas of enamel rods cut in cross-section dispersed between areas of rods cut longitudinally.

The portion of the pituitary gland that arises from an outgrowth of the hypothalamus is the: • Adenohypophysis • Neurohypophysis • Pars nervosa • Infundibulum

Neurohypophysis Remember: The posterior lobe forms from an outgrowth of the hypothalamus and contains axons from the neurosecretory cells of the hypothalamus, along with neuroglia-like cells (pituicytes). The anterior lobe (adenohypophysis) is formed from an invagin-ation of the pharyngeal epithelium (Rathke's pouch) -- thus, the epithelial nature of its cells. Important: 1. The anterior pituitary or adenohypophysis is a classical gland composed predomi-nantly of cells that secrete protein hormones. 2. The posterior pituitary or neurohypophysis is not really an organ but an extension of the hypothalamus. It is composed largely of the axons of hypothalamic neurons that extend downward as a large bundle behind the anterior pituitary. It also forms the so-called pituitary stalk, which appears to suspend the anterior gland from the hypothal-amus. The tropic hormones (FSH, LH, ACTH, and TSH) are hormones that affect the activity of another endocrine gland. Releasing or inhibiting hormones produced by the hypothalamus control these hoiniones of the anterior pituitary. Prolactin and growth hormone (GH) also made in the anterior pituitary are not considered to be tropic hormones. Secretory cells of the anterior pituitary are categorized into two groups, according to their staining properties. • Acidophils (acidic stain): secrete GH, and prolactin • Basophils (basic stain): secrete TSH, FSH, LH, and ACTH

The mylohyoid nerve is derived from the inferior alveolar nerve just before it enters the mandibular foramen. The mylohyoid nerve descends in a groove on the deep surface of the ramus of the mandible, to the supply the: • Anterior and posterior belly of the digastric muscle • Mylohyoid and anterior belly of the digastric muscles • Stylohyoid and posterior belly of the digastric muscles • Geniohyoid and stylohyoid muscles

Nlylonyoid and anterior belly of the digastric muscles *** The mylohyoid nerve arises from the inferior alveolar nerve, a branch of the man-dibular division (V-3) of the trigeminal nerve (V). Function of mylohyoid: elevates hyoid bone, base of tongue, and floor of mouth. The mylohyoid line, which gives origin to the mylohyoid, is found on the body of the mandible. The sublingual gland is located superior to the mylohyoid muscle. When film is placed for a periapical view of the mandibular molars, it is the mylohyoid muscle that gets in the way if it is not relaxed. Important: Swelling at the angle of the mandible and the lateral neck is often the result of deflection of exudates by the mylohyoid muscle. • Suprahyoid muscles: - Digastric muscles - Anterior belly: innervated by nerve to the mylohyoid, which is a branch of the mandibular division of the trigeminal nerve - Posterior belly: innervated by the facial nerve - Mylohyoid muscle: innervated by nerve to the mylohyoid, which is a branch of the mandibular division of the trigeminal nerve - Geniohyoid muscle: innervated by the first cervical nerve through the hypoglos- sal nerve - Stylohyoid: innervated by the facial nerve • Infrahyoid muscles: - Omohyoid muscle: innervated by ansa cervicalis Cl, 2, and 3 - Sternohyoid muscle: innervated by ansa cervicalis Cl, 2, and 3 - Sternothyroid muscle: innervated by ansa cervicalis C1, 2, and 3 - Thyrohyoid muscle: innervated by the first cervical nerve, which accompanies the hypoglossal nerve to the suprahyoid region, and then branches from it to reach the thyrohyoid muscle

The following is the site of synthesis of rRNA: • Endoplasmic reticulum • Ribosomes • Golgi apparatus • Nucleolus • Plasma membrane

Nucleolus The nucleolus is an oval body found inside the nucleus. The nucleolus consists of RNA and protein and is not bounded by a limiting membrane. The nucleolus is the site of rRNA synthesis. Ribosomes are small particles consisting of rRNA and protein. They are commonly called the "protein factories" of the cell. They are responsible for the process of translation, or taking the information from the DNA, encoding on RNA, and using it to create the proteins needed by the cell. The endoplasmic reticulum is a membranous network through the cytoplasm. The endoplasmic reticulum is continuous with the cell and nuclear membranes. There are two types of endoplasmic reticulum: 1. Smooth (ribosomes are absent) -- steroid synthesis; intercellular transport; detoxi-fication. 2. Rough (ribosomes are attached) -- synthesis of proteins for use outside a cell (extracellular use). 1. The nucleus of a cell is surrounded by two membranes and contains DNA. Notes 2. Active cells (fibroblasts, osteoblasts, etc.) are characterized by an abundance of rough endoplasmic reticulum. 3. RNA and DNA can be distinguished from one another by the Feulgen reaction.

Which of the following fiber groups of the alveolodental ligament is the most numerous of the fiber groups and covers the apical two-thirds of the root? • Alveolar crest group • Horizontal group • Apical group • Interradicular group • Oblique group

Oblique group The principal fibers of the PDL are primarily composed of bundles of type I collagen fibrils. These fibers connect the cementum to the alveolar bone. The main principal fiber group is the alveolodental ligament, which consists of five fiber groups: Alveolodental ligament: • The alveolar crest group of the alveolodental ligament: originates in the alveolar crest of the alveolar bone proper and fans out to insert into the cervical cementum at various angles. The function of this group is to resist tilting, intrusive, extrusive, and rotational forces. • The apical group of the alveolodental ligament radiates from the apical region of the cementum to insert into the surrounding alveolar bone proper. The function of this group is to resist extrusive forces, which try to pull the tooth outward, and rotational forces. • The oblique group of the alveolodental ligament: the most numerous of the fiber groups and covers the apical two-thirds of the root. This group originates in the alveolar bone proper and extends apically to insert more apically into the cementum in an oblique manner. The function of this group is to resist intrusive forces, which try to push the tooth inward, as well as rotational forces. • The horizontal group of the alveolodental ligament: originates in the alveolar bone proper apical to its alveolar crest and inserts into the cementum horizontally. The function of this group is to resist tilting forces, which work to force the tip either mesially, distally, lingually, or facially, and to resist rotational forces. • The interradicular group of the alveolodental ligament: found only in multirooted teeth. This group is inserted on the cementum of one root to the cementum of the other root (or roots) superficial to the interradicular septum and thus has no bony attachment. The function of this group is to work together with the alveolar crest and apical groups to resist intrusive, extrusive, tilting, and rotational forces. Note: Another principal fiber other than the alveolodental ligament is the interdental ligament, or transseptal ligament. This fiber group (called transseptal fibers) inserts mesially or interdentally into the cervical cementum of neighboring teeth over the alveolar crest of the alveolar bone proper. Thus, the fibers travel from cementum to cementum without any bony attachment. The function of this group is to resist rotational forces and thus hold the teeth in interproximal contact. Important: The ends of the principal fibers, which are embedded into the cementum and alveolar bone, are called Sharpey's fibers.

Which cerebral lobe is the visual processing center of the human brain? ) • Parietal lobe • Occipital lobe • Temporal lobe • Frontal lobe

Occipital lobe The cerebrum or cortex (the extensive outer layer of gray matter of the cerebral hemispheres) is the largest part of the human brain, associated with higher brain function such as thought and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe. Note: (1) The limbic system, often referred to as the "emotional brain," is found buried within the cerebrum. (2) Basal nuclei are gray mat¬ter structures deep within each cerebral hemisphere that help to control skeletal muscle activ¬ity.

Which of the following nerves carries parasympathetic fibers in addition to motor innervation? • Optic (CN II) • Olfactory (CN I) • Oculomotor (CN III) • Trochlear (CN IV)

Oculomotor (CN III) The four extraocular muscles that the oculomotor nerve innervates are the: • Superior rectus muscle • Middle rectus muscle • Inferior rectus muscle • Inferior oblique muscle

A patient with uncontrolled diabetes comes into the clinic for some periodontal work. You notice that her right eyelid is now drooping, which it was not doing a year ago at her last appointment. From class, you recognize that nerve damage can be the result of chronic high blood sugar. An upper eyelid that droops (ptosis) may be caused by damage to the: • Trochlear nerve (CN IV) • Abducens nerve (CN VI) • Oculomotor nerve (CN III) • Optic nerve (CN II)

Oculomotor nerve (CN III) The oculomotor nerve supplies the following extraocular muscles: medial, superior, and inferior recti; inferior oblique; and levator palpebrae superioris. The oculomotor nerve sends preganglionic parasympathetic fibers to the ciliary ganglion. The postganglionic fibers leave the ganglion in the short ciliary nerves to supply the sphincter pupillae and the ciliary muscle. Note: In most cases, ptosis is caused by either a weakness of the levator muscle (muscle that raises the lid), or a problem with the oculomotor nerve. Remember: The trochlear nerve (CN IV) supplies the superior oblique muscle (the muscle that turns the eyeball inferiorly and laterally), and the abducens nerve (CN VI) supplies the lateral rectus of the eye. The oculomotor nerve (CN III), trochlear nerve (CN IV), and abducens nerve (CN VI) all exit the cranium through the superior orbital fissure. They innervate the extrinsic ocular muscles, resulting in movements of the eyeball. Note: The trochlear nerve is the smallest cranial nerve and the only cranial nerve that emerges from the dorsal (back) aspect of the brainstem.

Which type of epithelium provides sensory innervation that travels on nerve bundles through the cribriform plate?

Olfactory epithelium -- specialized columnar epithelium

Which type of neuroglial cells form myelin in the CNS? • Astrocytes • Oligodendrocytes • Microglia • Ependymal cells

Oligodendrocytes Neuroglial cells, the other major cell type in neural tissue, provide structural integrity to the nervous system and functional support that enables neurons to perform. Neuroglia do not typically have synapses at their surface. Classically neuroglial cells are described as existing only in the central nervous system (brain and spinal cord). Cells in the PNS that support neurons include Schwann cells and satellite cells. Note: With the exception of microglia, which derive from mesoderm, all neuroglia derive from ectoderm.

Expansion of the pituitary gland by a tumor can put pressure on the crossing-over fibers at this X-shaped structure formed by the meeting of the two optic nerves. The name of this structure is: • Optic tract • Lateral geniculate body • Optic chiasma • Medial geniculate body

Optic chiasma The optic nerve (CN II) arises from axons of ganglion cells of the retina, which converge at the optic disc. The optic nerve leaves the orbital cavity by passing through the optic foramen (also called optic canal) of the sphenoid bone with the ophthalmic artery and then enters the cranial cavity. The nerves on both sides join one another to form the optic chiasma. Here, the nerve fibers that arise from the medial (nasal) half of each retina cross the midline and enter the optic tract of the opposite side; the fibers from the lateral (temporal) half of each retina pass posteriorly in the optic tract of the same side. The optic tract emerges from the posterolateral angle of the optic chiasma and passes backward around the lateral side of the midbrain to reach the lateral geniculate body. Remember: The optic nerves carry impulses associated with vision. Like the olfactory nerves, the optic nerves are entirely sensory. The optic nerves are actually brain tracts rather than true nerves, since the optic nerves are formed from outgrowths of the embryonic diencephalon.

The only part of the retina that does not contain photoreceptors, and contains the axons of ganglion cells that form the optic nerve, is known as the:i • Photo spot • Optic chiasm • Lens • Oculomotor nerve (CN HI) • Optic disc

Optic disc The optic disc (also called the optic papilla) is the small blind spot on the surface of the retina, located about 3 mm to the nasal side of the macula. The optic disc is the only part of the retina that contains no photoreceptors (rods or cones). The disc consists of axons of ganglion cells exiting the retina to form the optic nerve. These axons are accompanied by the central artery and vein of the retina. The optic nerve has only a special sensory component. Special sensory conveys visual information from the retina (special afferent). Visual information enters the eye in the form of photons of light that are converted to electrical signals in the retina. These signals are carried via the optic nerves, chiasma, and tract to the lateral geniculate nucleus of each thalamus and then to the visual centers of the brain for interpretation. Remember: After exiting the eye at the optic disc, the two optic nerves (one from each eye) meet at the optic chiasma. It is here that the axons from the medial (nasal) half of each retina cross to the opposite side, while those from the lateral half of each retina remain on the same side. From the optic chiasma, axons that perceive the left visual field form the right optic tract. These optic tract fibers synapse in the lateral geniculate nuclei with geniculocalcarine fibers (optic radiations) that terminate on the banks of the calcarine sulcus in the primary visual cortex (Brodmann's area 17) of the occipital lobe. Thus, the right visual field is interpreted in the left hemisphere of the brain and vice versa. Note: The central artery of the retina, a branch of the ophthalmic artery, pierces the optic nerve and gains access to the retina by emerging from the center of the optic disc.

Origin, insertion, action, innervation Genioglossus Styloglossus Hyoglossus Palatoglossus

Origin: Superior genial spine of mandible Styloid process of temporal bone Body and greater cornu of hyoid bone Palatine aponeurosis Insertion: Dorsum of tongue Lateral side and dorsum of tongue Side of tongue Side of tongue Action: Protrudes apex of tongue through mouth Draws tongue upward and backward Depresses tongue Pulls root of tongue upward and backward, narrows oropharyngeal isthmus Innervation: Hypoglossal nerve Hypoglossal nerve Hypoglossal nerve Pharyngeal plexus

Osteoclasts and osteoblasts

Osteoclasts are cells that break down and remove exhausted bone tissue. Osteoblasts build new bone tissue to replace this loss. Osteoblasts are the principal bone-building cells; they synthesize collagenous fibers and bone matrix, and promote mineralization during ossification. Once this has been accomplished, the osteoblasts, which are trapped in their own matrix, develop into osteocytes that maintain the bone tissue. Osteoblasts are derived from mesenchyme (fibroblasts) and have a high `Notes' RNA content and stain intensely. Osteoclasts (which are derived from stem cells in the bone marrow-- the same ones that produce monocytes and macrophages) are large multinucleated cells that contain lysosomes and phagocytic vacuoles. Note: A Howship's lacuna is a small hollow created on the bone surface by osteoclastic activity. Osteoid is newly formed organic bone matrix that has not undergone calcification. Important: Osteoid differs from bone in that osteoid does not have a mineralized matrix. Remember: Bone is hard and resists compression because of the mineralization of its extracellular matrix. When bone matrix mineralizes, inorganic hydroxyapatite crystals (primarily calcium phosphate) are deposited around the existing collagen fibrils, and the water content of the matrix decreases. Bone derives its flexibility and tensile strength from its abundant collagen fibers.

A young woman with no secondary sexual characteristics, short stature, and webbed neck walks into the physician's office. Her medical history indicates a karyotype labeled 45,X. This woman, diagnosed with Turner's syndrome, is unable to conceive children, one reason potentially being that the site of oogenesis is non-functional. What is the site of oogenesis in a healthy female? • Ovary • Ovum • Oocyte • Oviduct • Ovarian lacunae

Ovary The ovaries are elliptical organs, situated close to the side walls of the pelvis, and are supported by the broad ligament of the uterus. All the ovary's blood and lymphatic vessels, and nerves enter at the hilum. Beneath its surface epithelium is a cortex that encloses the medulla at its core. The bulk of the ovary is the supporting structure called the stroma. Note: The main function of the ovaries is to produce mature ova. The cortex contains ova at different stages of development. The ova begin as primordial oocytes, sur-rounded by a layer of flat cells called granulosa cells. At puberty, the granulosa cells begin to multiply and form the multilayered theca interna that secretes estrogens; the surrounding stromal cells form the theca externa. A split appears in the theca interna and expands to form a fluid-filled cavity that pushes the oocyte to one side; the follicle is now a Graafian follicle. Ovulation takes place in the middle of each menstrual cycle -- a Graafian follicle ruptures to release its ovum, which enters the uterine tube. The empty follicle fills with blood and regresses into a corpus lu-teum. If the ovum is fertilized, the corpus luteum will persist and continue secreting progesterone to maintain pregnancy. If not, the corpus luteum shrinks into a small mass of collagenous tissue -- the cor-pus albicans. 1. Oogonia (singular: oogonium) are stem cells that give rise to the lifetime supply of oocytes that are present in the female's ovaries by the time she is born. Note: The oocytes begin to degenerate, and the process continues throughout adult life. These are called atretic follicles. 2. Primordial follicles containing primary oocytes in the sexually mature ovary are stimulated to develop by secretion of FSH from the anterior lobe of the pituitary. Primary follicles (in the first meiotic division) become secondary follicles with the formation of the antrum (cavity). Fully mature Graafian follicles containing secondary oocytes (in the second meiotic division) release the egg into the abdominal cavity under the influence of LH to be swept into the ostium of the fallopian tube (uterine tube, oviduct) to be fertilized and subsequently implanted in the uterus or discarded if not fertilized. 3. During maturation of the egg, four daughter cells are produced, one of which is the large, fertilizable ovum, while the others are small, rudimentary cells called polar bodies or polocytes.

Major ascending tracts of the spinal cord Function, location, origin of the following: Lateral spinothalamic Anterior spinothalamic Fasciculi gracilis and cuneatus Anterior and posterior spinocerebellar

Pain, temperature, and crude touch opposite side Crude touch and pressure Discriminating touch and pressure sensations, including vibration, stereognosis, and two-point discrimination; also conscious kinesthesia Unconscious kinesthesia Lateral white columns Anterior white columns Posterior white columns Lateral white columns Posterior gray column opposite side Posterior gray column opposite side Spinal ganglia same side Anterior or posterior gray column Thalamus Thalamus Medulla Cerebellum

The anterior and posterior pillars of the fauces enclose which area of lymphoid tissue? • Lingual tonsils • Pharyngeal tonsils • Palatine tonsils

Palatine tonsils The fauces is a narrow passage from the mouth to the pharynx, situated between the soft palate and the base of the tongue; this is also called the isthmus of the fauces. On either side of the passage, two membranous folds, called the pillars of the fauces, enclose the palatine tonsils (consist of predominantly lymphoid tissue). The two arches formed by the anterior and posterior folds of mucous membrane are: 1. The glossopalatine (palatoglossus) arch (anterior pillar offauces or anterior fau¬cial pillar) on either side runs downward, lateralward, and forward to the side of the base of the tongue, and is formed by the projection of the palatoglossus muscle with its covering mucous membrane. 2. The pharyngopalatine (palatopharyngeal) arch (posterior pillar offauces or pos¬terior faucial pillar) is larger and projects farther toward the middle line than the ante¬rior; it runs downward, lateral, and backward to the side of the pharynx, and is formed by the projection of the palatopharyngeus muscle, covered by mucous membrane.

CAB of the muscles of the soft palate participate in closing the nasopharynx during swallowing EXCEPT one. Which one is the EXCEPTION? • Uvular muscle • Palatopharyngeus muscle • Tensor veli palati muscle • Palatoglossus muscle • Levator veli palati muscle

Palatoglossus muscle Five paired skeletal muscles of the soft palate: 1. Palatoglossus muscle: pulls the root of the tongue upward and backward. Both muscles contracting together cause the palatoglossal arches to approach the midline, and thus the opening (oropharyngeal isthmus) between the oral pharynx and the mouth is narrowed. 2. Palatopharyngeus muscle: pulls the walls of the pharynx upward. Acting togeth-er, the muscles pull the palatopharyngeal arches toward the midline. 3. Levator veli palati muscle: raises the soft palate. 4. Tensor veli palati muscle: the two muscles tighten the soft palate so that it may be moved upward or downward as a tense sheet. This muscle curves around the ptery-goid hamulus. Therefore, if the hamulus were fractured, the actions of this muscle would be affected. 5. Uvular muscle: raises (and shortens) the uvula to help seal oral from nasal phar-ynx. Important: All the paired skeletal muscles of the soft palate are innervated by the pharyngeal plexus except the tensor veli palati, which is innervated by a branch of the nerve to the medial pterygoid, which is a branch of the mandibular division of the trigeminal nerve (V-3). --- 1. The anterior zone of the palatal submucosa contains fat, while the `Notes posterior zone contains mucous glands. 2. The salivary glands of the hard palate are located in the posterolateral zone. They arise from ectoderm and are separated by connective tissue septa.

An aggressive duodenal ulcer has the potential to perforate the small intestine and involve other organs. A posteriorly penetrating ulcer has the potential to kz,...„ adhere to this organ, which is both an exocrine and endocrine organ. • Thymus gland • Pancreas • Thyroid gland • Parathyroid glands

Pancreas The pancreas is a retroperitoneal organ located posterior to the stomach on the posterior abdominal wall. The pancreas's large head is framed by the C-shaped loop of the duodenum, while the tail touches the spleen. The pancreas plays a role in both the digestive and endocrine systems. The pancreas is covered in a tissue capsule that partitions the gland into lobules. Endocrine portion (islets of Langerhans — endocrine cells of pancreas): • Alpha cells -- secrete glucagon, which counters the action of insulin. • Beta cells -- secrete insulin, which helps carbohydrate metabolism. • Delta cells -- secrete somatostatin, which acts locally within the islets of Langerhans themselves to depress the secretion of both insulin and glucagon. Important: The degeneration of the islets of Langerhans leads to diabetes mellitus. Exocrine portion: • Acinar cells (pancreatic exocrine cells) -- these cells are filled with secretory gran¬ules containing the digestive enzymes (mainly trypsin, chymotrypsin, pancreatic lipase, and amylase) that are secreted into the lumen of the acinus. Remember: Pancreatic secretions contain bicarbonate ions and are alkaline in order to neutralize the acidic chyme that the stomach chums out.

Which cells, located in the crypts of Lieberkuhn, secrete an antibacterial enzyme that maintains the gastrointestinal barrier? • Paneth cells • Enteroendocrine cells • Sertoli cells • Absorptive cells

Paneth cells Characteristic features of the small intestine include: • Intestinal villi. These are finger-like projections into the lumen (consisting of surface epithelium and underlying lamina propria). *** The epithelium lining the lumen consists of a simple columnar epithelium with goblet cells. The apical surface of the absorptive epithelial cells has a "brush border" (resulting from an order¬ly arrangement of closely-packed microvilli, which may number several hundred per absorptive cell). The main function of the microvilli is to increase the surface area available for absorption. *** The lamina propria of the small intestine is formed from loose connective tissue. This contains blood vessels, nerves, and large lymphatic vessels (site of absorption of lipids). • Intestinal glands. These are simple tubular glands that open to the intestinal lumen between the base of the villi. The intestinal glands are sometimes called the crypts of Lieberkuhn. Secretory cells (Paneth cells) with large acidophilic granules are found at the base of the intestinal glands. Their function is still not fully understood, but it is known that they secrete lysozyme, which has anti-bacterial properties and helps maintain the gastrointestinal barrier. • Valves of Kerckring. The lining of the small intestine has permanent folds known as valves of Kerckring or plicae circulares. These are most prominent in the jejunum. These folds, seen macro¬scopically in transverse sections, consist of mucosa and submucosa. Three types of epithelial cells line the microvilli of the "brush border": 1. Goblet cells: secrete mucus, abundant in ileum. 2. Absorptive cells: participate in absorption, simple columnar cells. 3. Enteroendocrine cells: secrete enterogastrones (secretin and cholecystokinin) into the blood-stream. Abundant in the duodenum. Remember: 1. Brunner's glands (also called duodenal glands or submucosal glands) are small, branched, coiled, tubular glands situated deeply in the submucosa of the duodenum. These glands secrete an alkaline mucus to protect the walls of the intestinal juice. 2. The ileum contains aggregates of mesenteric lymph nodes called Peyer's patches, which inter-cept and destroy bacteria before they are absorbed by the digestive tract.

The ciliary, pterygopalatine, submandibular, and otic ganglia are all: • Sympathetic ganglia • Parasympathetic ganglia • Both sympathetic and parasympathetic ganglia • Neither sympathetic nor parasympathetic ganglia

Parasympathetic ganglia Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system. Most are small terminal ganglia or intramural ganglia, so named because they lie near or within the organs they innervate. Parasympathetic ganglia: • CN III = Ciliary ganglion — eye • CN VII = Pterygopalatine and submandibular ganglion -- eye and nasal mucosa • CN IX = Otic ganglion -- parotid salivary gland • CN X = To ganglia on each organ • S2-S4 = To large intestine, rectum, genitalia, ureters, and urinary bladder *** Neurotransmitter is acetylcholine at pre- and postganglionic synapses Sympathetic ganglia: organized into two chains that run parallel to and on either side of the spinal cord. • Paravertebral ganglia: lie on each side of the vertebrae and are connected to form the sympathetic chain or trunk. There are usually 21 or 23 pairs of these ganglia: 3 in the cervical region, 12 in the tho-racic region, 4 in the lumbar region, 4 in the sacral region, and a single, unpaired ganglion lying in front of the coccyx called the ganglion impar. • Cervical ganglia — superior, middle or inferior cervical ganglion • Thoracic, lumbar and sacral ganglia • Prevertebral (or preaortic) ganglia: provide axons that are distributed with the three major gas-trointestinal arteries arising from the aorta • Celiac ganglion • Superior and inferior mesenteric ganglion • Inferior hypogastric ganglion *** Neurotransmitter is norepinephrine (NE), except on adrenal medulla where it is acetylcholine. White ramus and gray ramus communicans: • White ramus communicans: All sympathetic preganglionic neurons enter the paravertebral gan-glion chain via the white ramus communicans. They are white because the nerves are myelinated. • Gray ramus communicans carry unmyelinated postganglionic sympathetic nerves to peripheral organs. They are gray because they are unmyelinated.

A nervous dental student is performing the inferior alveolar nerve block for the first time. His injection passes the ramus, but he thinks deposition of the anesthetic will work. His patient complains that he can't "move his face" on the side of the injection. Which gland did the dental student penetrate?) • Sublingual gland • Submandibular gland • Parotid gland • Von Ebner's glands

Parotid gland If the needle mistakenly passes posteriorly at the level of the mandibular foramen, the needle will penetrate the parotid gland, and the patient may develop paralysis of the muscles of facial expression. If the tip of the needle is resting well below the mandibular foramen, you will be penetrating the medial pterygoid muscle. Correct needle penetration into the pterygomandibular space during an inferior alveolar block. If the needle is inserted too far posteriorly, it may enter the parotid salivary gland containing the facial nerve, caus¬ing a complication such as transient facial paralysis.

All of the following contain mucus-secreting cells EXCEPT one. Which one is the EXCEPTION? • Submandibular glands • Sublingual glands • Parotid glands • Glands of the esophagus • Mucosa of the trachea

Parotid glands *** Remember: These glands are completely serous. Both the major and minor salivary glands are composed of both epithelium and connective tissue. Epithelial cells both line the duct system and produce the saliva. Connective tissue surrounds the ep¬ithelium, protecting and supporting the gland. The connective tissue of the gland is divided into the capsule, which surrounds the outer portion of the entire gland, and septa. Each septum helps divide the inner portion of the gland into larger lobes and smaller lobules. Epithelial cells that produce saliva are called secretory cells. The two types of secretory cells are classified as either mucous or serous cells. Secretory cells are found in a group, or acinus (plural, acini), which resembles a cluster of grapes. Each acinus consists of a single layer of cuboidal cells, epithelial cells surrounding a lumen, a central opening where the saliva is deposited after being pro¬duced by the secretory cells. The three forms of acini are classified in terms of the type of epithelial cell present and the secretory product being produced. Serous Acini: • Composed of serous cells producing a serous secretory product; are generally spherical with a narrow lumen • Serous cells contain large amounts of rER, free ribosomes, a prominent Golgi complex, and numerous protein-rich, membrane-bound vesicles called secretory granules. In cells that pro¬duce digestive enzymes, these vesicles are called zymogen granules Mucous Acini: • Composed of mucous cells producing a mucous secretory product; are usually more tubu¬lar with a wider lumen • Most mucous cells contain large numbers of mucinogenic granules in their apical cytoplasm Mixed Acini: • Have both mucous cells surrounding the lumen and a serous demilune or cap of serous cells superficial to the group of mucous secretory cells • These caps, or serous demilunes, secrete into the highly convoluted intercellular space, be¬tween the mucous cells. *** They are associated with the mixed acini of the sublingual and submandibular glands as well as the glands of the esophagus and trachea

A fibrous connective tissue sheath containing blood vessels that surrounds most cartilage is called the: • Pericardium • Perichondrium • Periosteum • Pericranium

Pcrichondrium Cartilage is a type of dense, fibrous connective tissue, which supports and shapes various struc¬tures. It also cushions and absorbs shock. Cartilage is composed of cells called chondrocytes that are dispersed in a firm, gel-like ground substance, called the matrix. These cells reside in de¬pressions in the matrix, called lacunae. Cartilage contains no blood vessels, and nutrients are dif¬fused through the matrix. Cartilage is found in the joints, the rib cage, the ear, the nose, and the throat and between intervertebral discs. Note: The only blood supply to cartilage is provided by blood vessels that enter the cartilage through the perichondrium. Important: The exception to the rule that cartilage is always covered by a perichondrium is the articular cartilage at a synovial joint. There are three subtypes based on the composition of the matrix: 1. Hyaline cartilage -- has a high proportion of matrix and fine collagenous fibers. Throughout childhood and adolescence, hyaline cartilage plays an important part in the growth in length of long bones (epiphyseal plates are composed of hyaline cartilage). Covers the ar¬ticular surfaces of nearly all synovial joints. It is incapable of repair when fractured. Note: Type II collagen makes up 40% of this cartilage's dry weight. 2. Fibrocartilage -- has a large number of collagen fibers embedded in a small amount of ma¬trix. Fibrocartilage is found in the discs within joints (e.g., the TMJ, sternoclavicular joint, and knee joint) and on the articular surfaces of the clavicle and mandible. 3. Elastic cartilage -- similar to hyaline cartilage, except elastic cartilage possesses large num¬bers of elastic fibers embedded in the matrix. Elastic cartilage is very flexible and is found in the auricle of the ear, the external auditory meatus, the auditory tube, and the epiglottis. 1. Cartilage is a precursor to endochondral bone. 2. The matrix is mainly composed of proteoglycans, a special type of glycosamino-glycans. The most common types are chondroitin sulfate and keratan sulfate. 3. The perichondrium is very important in the growth of cartilage. 4. No calcium salts are present and, therefore, cartilage doe not appear on x-rays.

r The axilla, or armpit, is a localized region of the body between the upper humerus and thorax. It provides a passageway for the large, important arteries, nerves, veins, and lymphatics that ensure that the upper limb functions properly. The muscle that forms the bulk of the anterior axillary fold is the: • Latissimus dorsi • Pectoralis major • Subscapularis • Teres minor • Teres major

Pectoralis major The axilla can be visualized as having a floor, an apex, and four walls (medial, lateral, anterior, and posterior). • The apex is pointing toward the root of the neck. It is formed by the convergence of the clavicle (anterior), the scapula (posterior), and the first rib (medially). All the nerves and vessels of the upper limb pass through this area. • The anterior axillary fold is made up of the pectoralis major and minor muscles. • The posterior axillary fold is made up of the latissimus dorsi and teres major muscles. • The base faces inferiorly and is formed by the skin and fascia of the concave axilla (armpit). • The medial wall is formed by the upper four or five ribs and their intercostal muscles and the serratus anterior muscle. • The lateral wall is formed by the humerus (specifically, the coracobrachialis and biceps muscles in the bicipital groove of the humerus). • The posterior wall is formed by the subscapularis, teres major, and latissimus dorsi muscles. • The anterior wall is formed by the pectoralis major, minor, and subclavius musc-les. Contents of the axilla: • The axillary vessels • Branches of the brachial plexus • Both heads of the biceps brachii • Coracobrachialis

Which of the following muscles pulls the shoulder downward and forward?) • Pectoralis major • Pectoralis minor • Teres major • Teres minor • Deltoid • Latissimus dorsi

Pectoralis minor

Hospital tests on a patient identify a tumor in the hypophysis that is excessively secreting growth hormone. Given that the patient is a 4-year-old male, what is the expected outcome if no treatment is performed? • Pituitary giantism • Acromegaly • Pituitary dwarfism • Achondroplasia

Pituitary giantism The amount of growth hormone secreted by the anterior pituitary gland can have a dramatic effect on bone development: • Pituitary giant -- tumor prior to adolescence, excessive GH delays ossification of epiphyseal cartilage (non fusionof epiphyses). • Acromegaly -- tumor after adolescence, excess GH secreted after epiphyseal cart-ilages have been replaced by bone (fusion of epiphyses). • Pituitary dwarf -- GH deficiency resulting in early replacement of epiphyseal cartilages by bone. Important point: The deciding factor in whether gigantism or acromegaly will occur when there is oversecretion of growth hormone by the pituitary gland is whether the epi¬physes of the long bones have fused with the shaft or not. Two lobes of the pituitary gland (hypophysis cerebri): 1. Posterior lobe -- unmyelinated nerve fibers, secretes ADH and oxytocin. 2. Anterior lobe • Alpha cells (acidophils; stain strongly with acid dyes) 1. Somatotropes -- secrete GH 2. Lactotropes -- secrete prolactin • Beta cells (basophils; stain strongly with basic dyes) 1. Corticotropes -- secrete ACTH 2. Gonadotropes -- secrete FSH and LH 3. Thyrotropes -- secrete TSH *** The pars intermedia and tuberalis have no proven function in mammals.

The portal venous system occurs when one capillary bed drains into another capillary bed through veins. There are three portal systems in the human body: the hepatic portal system, the renal portal system, and a portal system involving which endocrine gland? • Pancreas • Thyroid gland • Pituitary gland • Adrenal gland

Pituitary gland A portal venous system occurs when a capillary bed drains into another capillary bed through veins. Both capillary beds and the blood vessels that connect the beds are con-sidered part of the portal venous system. They are relatively uncommon as the majority of capillary beds drain into the heart, not into another capillary bed. Portal venous systems are considered venous because the blood vessels that join the two capillary beds are ei¬ther veins or venules. Examples of such systems include the hepatic portal system, the hypophyseal portal system, and the renal portal system. Blood supply to the pituitary gland is from the right and left superior hypophyseal ar¬teries and from the right and left inferior hypophyseal arteries, which are branches of the internal carotid artery. These form the rich vascular hypophyseal portal system. This system of blood vessels links the hypothalamus and the anterior pituitary. This system al¬lows endocrine communication between the two structures. The veins drain into the in-tercavernous sinuses. Important: The neurohypophysis contains abundant axons whose cell bodies are lo¬cated mainly in the supraoptic and paraventricular nuclei of the hypothalamus.

Which gland is sometimes called the "master" gland of the endocrine system, because this gland controls the functions of the other endocrine glands? • Pancreas • Thymus gland • Parathyroid glands • Pituitary gland

Pituitary gland (also called the hypophysis) The pituitary gland is no larger than a pea (weighs only 0.5 gram), and rests in the sella turcica, a depression in the sphenoidal bone at the base of the brain. The pituitary connects with the hypothalamus via the infundibulum, through which this gland receives chemical and neural stimuli. The pituitary gland is often referred to as the "master endocrine gland" because it controls so many other glands. It does this through the action of tropic hormones -¬hormones that affect the activity of another endocrine gland. For this reason, the pituitary gland is vital to life. The pituitary develops from two different sources: an upgrowth from the ectoderm of the stomodeum and a downgrowth from the neuroectoderm of the diencephalon, in other words, an upgrowth from the roof of the mouth and a downgrowth from the floor of the brain. This double origin explains why the pituitary gland is composed of two completely different types of tissue. The adenohypophysis (glandular portion) arises from the oral ectoderm, and the neurohypophysis (nervous portion) originates from the neuroectoderm. During the developmental stage (about three weeks), a diverticulum called Rathke's pouch arises from the roof of the stomodeum (primitive mouth) and grows toward the brain. As this pouch approaches the developing neurohypophysis (posterior lobe), its attachment with the mouth is lost. The pouch then goes on to form the portion of the pituitary gland known as the adenohypophysis (anterior lobe).

The trachea bifurcates into right and left primary bronchi at the level of the

Plane of the sternal angle

Functions: Membranous: Plasma membrane Endoplasmic reticulum Golgi apparatus Lysosomes Peroxisomes Mitochondria Nucleus Nonmembranous: Ribosomes Cytoskeleton Nucleolus

Plasma membrane Serves as a boundary of the cell, maintaining its integrity; protein molecules embedded in plasma membrane perform various functions; for example, they serve as markers that identify cells of each individual, as receptor molecules for certain hormones and other molecules, and as transport mechanisms Endoplasmic reticulum Ribosomes attached to rough ER synthesize proteins that leave cells via the Golgi complex; smooth ER synthesize lipids incorporated in cell membranes, steroid hormones, and certain carbohydrates used to form glycoproteins Golgi apparatus Synthesizes carbohydrate, combines it with protein, and packages the product as globules of glycoprotein Lysosomes A cell's "digestive system" Peroxisomes Contain enzymes that detoxify harmful substances Mitochondria Catabolism; ATP synthesis; a cell's "power plant" Nucleus Houses the genetic code, which in turn dictates protein synthesis, thereby playing an essential role in other cell activities, namely, cell transport, metabolism, and growth Nonmembranous Ribosomes Site of protein synthesis; a cell's "protein factories" Cytoskeleton Acts as a framework to support the cell and its organelles; functions in cell movement; forms cell extension (microvilli, cilia, flagella) Nucleolus Plays an essential role in the formation of ribosomes

A pneumothorax is the presence of air into which space?

Pleural cavity:A penetration wound of the chest wall can lead to a pneumothorax (air in the pleural cavity) or a hemothorax (blood in the pleural cavity). In both of these situations, the surface tension that binds the lungs to the chest wall is eliminated, and the lung will instantly shrink to the size of a tennis ball. The lungs fill the pleural divisions of the thoracic cavity; they extend from the root of the neck to the diaphragm. The lungs are the main component of the respiratory system; they distribute air and exchange gases. The right and left lungs are separated by the mediastinum, which contains the heart, blood vessels, and other midline structures; fissures divide each lung into lobes. Each primary bronchus enters its respective lung at the hilus, an indentation on the mediastinal surface. The bronchi and pulmonary blood vessels are bound together by connective tissue to form the root of the lung. The base, the inferior surface of the lung, rests on the diaphragm. The apex, the most superior portion of the lung, projects above the clavicle.

Which cranial fossa houses the cerebellum, medulla, and pons?

Posterior cranial fossa: The internal surface of the base of the skull consists of three cranial fossae, the anterior, middle, and posterior. They increase in size and depth from anterior to posterior. The anterior and middle fossae are separated by the lesser wing of the sphenoid bone, and the middle and posterior fossae are separated by the petrous part of the temporal bone. The anterior cranial fossa is adapted for reception of the frontal lobes of the brain, and is formed by portions of the frontal, ethmoid, and sphenoid bones. The crista galli, a midline process of the ethmoid bone, gives attachment to the anterior end of the falx cerebri. On each side of the crista galli are the grooved cribriform plates of the ethmoid bone, providing numerous orifices for the delicate olfactory nerves from the nasal mucosa to synapse in the olfactory bulbs.

Diabetes insipidus is characterized by the secretion of large amounts of dilute urine because of a deficiency in antidiuretic hormone. Antidiuretic hormone is secreted from the: • Anterior pituitary • Posterior pituitary • Adrenal medulla • Adrenal cortex • Thyroid

Posterior pituitary The pituitary has two main regions. The larger region, the anterior pituitary (adenohy-pophysis), produces at least six hormones: Mnemonic --- GPA B-FLAT = GH, Prolactin from Alpha cells. Beta cells: FSH, LH, ACTH, TSH. 1. Growth hormone (GH) -- promotes growth in general, particularly the skeletal sys¬tem. 2. Corticotropin (ACTH) -- controls the secretion of adrenocortical hormones, which in turn affect the metabolism of glucose, proteins, and fat. 3. Thyroid-stimulating hormone (TSH) -- controls secretion of thyroxine by the thy-roid. 4. Prolactin -- promotes mammary gland development and milk production. 5. Follicle-stimulating hormones (FSH) -- stimulates growth of Graafian follicles in the ovary and promotes spermatogenesis in the male. 6. Luteinizing hormone (LH) -- stimulates secretion of sex hormones by the ovary and testis. The posterior pituitary, which makes up about 25% of the gland, serves as a storage area for: 1. ADH (antidiuretic hormone or vasopressin) -- controls the rate of water excretion into the urine. 2. Oxytocin -- helps to deliver milk from the glands of the breast to the nipples during nursing. Note: ADH and oxytocin are produced in the hypothalamus and transported in axons to the posterior lobe of the hypophysis for storage and secretion.

A 10-year-old girl comes into the physician with complications from Group A streptococcal infection, namely rheumatic fever. She is presenting with aortic valve stenosis, which is causing her dizziness and syncopal episodes. In the healthy heart, during diastole, the aortic valve: • Prevents reflux of blood into the right ventricle • Prevents reflux of blood into the right atrium • Prevents reflux of blood into the left atrium • Prevents reflux of blood into the left ventricle

Prevents reflux of blood into the left ventricle There are four valves that keep blood flowing in one direction through the heart: • The right and left atrioventricular valves -- separate the atrium and ventricle on the left and right sides of the heart, respectively. - Tricuspid valve or right AV valve -- guards the right atrioventricular orifice; consists of three cusps. This valve controls the flow of blood through the right AV opening. Note: Thin but strong fibrous cords of the chordae tendineae attach the cusps of this valve to the papillary muscles of the right ventricle. - The mitral valve or left AV valve -- guards the left atrioventricular orifice; consists of two cusps. Chordae tendineae attach these cusps to papillary muscles of the left ventricle. Important: Overdistension of the valves of the atrioventricular orifices of the heart is prevented by the papillary muscles and the trabeculae carneae (muscle ridges and bulges lining the right ventricle of the heart). • The semilunar valves: - Pulmonary valve -- guards the pulmonary orifice (between the right ventricle and the pulmonary artery); consists of three semilunar cusps. - Aortic valve -- guards the aortic orifice; consists of three semilunar cusps. Note: When these valves are closed it prevents backflow of blood into the left ventricle. *** Important: There are no chordae tendineae or papillary muscles associated with these valve cusps. Papillary muscles are found only in the ventricles of the heart.

The root of the lung contains the following structures:

Primary bronchus: the right and left bronchi arise from the trachea and carry air to the hilum of the lung during inspiration and carry air from the lung during expiration A pulmonary artery: enters the hilum of each lung carrying oxygen-poor blood Pulmonary vein(s): a superior and inferior pair for each lung leave the hilum carrying oxygen-rich blood

Surface Features of Bone (enlargements and processes):

Process: the most generic term for bone projection that serves as a point for attachment of other structures.Example: Acromion process of the scapula, transverse process of vertebrae.Epicondyle: a projection or swelling on a condyle (or above, in some cases) Example: Medial and lateral epicondyles of femur.Spine: a sharp, slender projecting process. Example: Spinous process of vertebrae, spine of the scapula.Tubercle: a small, rounded process. Example: Greater and lesser tubercles of humerus.Tuberosity: a large, rounded, roughened process. Example: Ischial tuberosity of the ischium.Trochanter: a large blunt projection for muscle attachments on the femur Example: Greater and lesser trochanters of the femur.Crest: a prominent elevated ridge or border of a bone. Example: Iliac crest of the ilium.Linea (line): a small crest, usually somewhat straighter than a crest Example: Linea aspera of femur.Ramus: a major branch or division of the main body of a bone. This may have its own articulations or processes. Example: The coronoid and condylar processes of the mandible are subdivisions of the ramus.Neck: a slight narrowing of the body of the bone that supports the head Example: Necks of the humerus and femur.Lamina: a very thin layer of bone. Example: The laminae of the vertebrae.

Organs of the Male Reproductive System Function: Testes (2) Scrotum Epididymis (2) Ductus (vas) deferens (2) Prostate gland Seminal vesicles (2 pair) Bulbourethral glands Ejaculatory ducts (2) Penis

Produce sperm and testosterone (male sex hormone) Encloses and protects testes Portion of the seminal duct in which sperm mature and are stored Transport sperm during ejaculation upward inside the spermatic cord to the urethra Produces semen, the fluid that carries sperm; this fluid helps protect sperm from the vagina's acidity during ejaculation Secrete the majority of the fluid (alkaline and rich in fructose) in semen Secrete fluid that lubricates urethra and end of penis Receive sperm and additives to produce seminal fluid; run through the prostate and open into the urethra Male sexual organ that passes both urine and sperm

Organs of the Female Reproductive System Function: Ovaries Uterine tubes (fallopian tubes) Uterus Vagina Labia majors Labia minora Clitoris Vestibular glands Mammary glands

Produces ova (female germ cells) and female sex hormones (estrogens and progesterone) Receive the ovum from the ovary and provide a site where fertilization of the ovum can take place. The tubes serve as a conduit along which the spermatozoa travel to reach the ovum Serves as a site for the reception, retention, and nutrition of the fertilized ovum Not only is the female genital canal but also serves as the excretory duct for the menstrual flow and forms part of the birth canal Form margins of pudendal cleft; enclose and protect other external reproductive organs Form margins of vestibule; protect openings of vagina and urethra Provides feeling of pleasure during stimulation Secrete lubricating fluid into the vestibule and vaginal opening during coitus Produce and secrete milk for nourishment of an infant

In which phase of mitosis does the chromatin condense into chromosomes and the nuclear envelope break down? • Interphase • Prophase • Metaphase • Anaphase • Telophase

Prophase Mitosis is the process of normal cell division. Mitosis occurs whenever body cells need to produce more cells for growth or for replacement and repair. The result of mitosis is two identical daughter cells with the same chromosomal content as the parent cell. Mitosis is part of the entire life span of the cell, also called the cell cycle. This entire cycle consists of the following stages: Interphase: the interval between successive cell divisions during which the cell is metabolizing and the chromosomes are directing RNA synthesis. It includes: 1. GI phase: the first growth phase 2. S phase: DNA synthesis 3. G2 phase: the second growth phase Mitosis can be divided into four principal stages: • Prophase: The chromatin, diffuse in interphase, condenses into chromosomes. Each chromosome has duplicated and now consists of two sister chromatids. At the end of prophase, the nuclear envelope breaks down into vesicles • Metaphase: The chromosomes align at the equatorial plate and are held in place by microtubules attached to the mitotic spindle and to part of the centromere • Anaphase: The centromeres divide. Sister chromatids separate and move toward the cor¬responding poles • Telophase: Daughter chromosomes arrive at the poles, and the microtubules disappear. The condensed chromatin expands, and the nuclear envelope reappears. The cytoplasm divides (cytokinesis), and the cell membrane pinches inward, ultimately producing two daughter cells The turnover rate of the cell varies greatly from one tissue to another. For example, there is rapid turnover in the epithelium of the alimentary canal and epidermis and slow turnover in the pancreas and thyroid.

Which of the following statements concerning the tongue is correct? • Protrusion of the tongue requires contraction of the genioglossus muscle • The tongue receives its major blood supply from the internal carotid artery • All extrinsic muscles are innervated by cranial nerve XII (hypoglossal) • General sensory innervation to the anterior two-thirds is provided by the glossopharyn¬geal nerve

Protrusion of the tongue requires contraction of the genioglossus muscle The extrinsic muscles (genioglossus, hyoglossus, styloglossus, and palatoglossus) anchor the tongue to the skeleton (mandible, hyoid, and temporal bones). These muscles control the protrusion (genioglossus), retraction (styloglossus), depression (hyoglossus and genioglossus), and lateral movement (palatoglossus) of the tongue. Remember: All extrinsic muscles end in - glossus (tongue) and begin with their site of origin. The intrinsic muscles lie entirely within the tongue itself. The fibers of these muscles are named according to the three spatial planes in which they run: longitudinal, trans-verse, and vertical. When these fibers or muscles contract, they squeeze, fold, and curl the tongue. All of the muscles of the tongue, both intrinsic and extrinsic, except the palatoglossus muscle, are innervated by the hypoglossal nerve. The palatoglossus muscle is innervat¬ed by the pharyngeal plexus. Note: The palatoglossus is a small extrinsic muscle of the tongue that arises from the soft palate and inserts in the tongue. The palatoglossus acts to elevate the tongue. The tongue receives its major blood supply from the lingual artery (which is a branch of the external carotid artery). Note: The terminal part of the lingual artery, the deep lingual artery, supplies the tip of the tongue. The veins drain into the internal jugular vein. Remember: The trigeminal nerve provides the sensory input to the anterior two-thirds of the tongue; the glossopharyngeal, the posterior portion.

Origin, Insertion, and action: Superior constrictor Middle constrictor Inferior constrictor

Pterygoid plate of the sphenoid bone Greater and lesser horns of hyoid; stylohyoid ligament Arch of cricoid and oblique line of thyroid cartilages Median pharyngeal raphe Median pharyngeal raphe Median pharyngeal raphe Constricts upper pharynx Constricts lower pharynx Constricts lower pharynx

Action: Serratus anterior Pectoralis minor Subclavius Trapezius Levator scapulae Rhomboid major Rhomboid minor

Pulls scapula forward and downward Pulls the shoulder downward and forward Depresses the clavicle and steadies this bone during movements of the shoulder girdle Suspends the shoulder girdle from the skull and the vertebral column. The upper fibers elevate the scapula. The middle fibers pull the scapula medially. The lower fibers pull the medial border of the scapula downward so that the glenoid cavity faces upward and forward Raises the medial border of the scapula With the rhomboid minor and levator scapulae, it elevates the medial border of the scapula and pulls it medially With the rhomboid major and levator scapulae, it elevates the medial border of the scapula and pulls it medially

A newborn boy of Jewish ancestry has been vomiting frequently. His parents bring him to the physician, who notes a narrowing (stenosis) of the opening from the stomach to the duodenum due to functional hypertrophy of the surrounding muscle. What is the name of the opening from the stomach into the small intestines? • Cardiac orifice • Pyloric sphincter • Lesser omentum • Greater omentum

Pyloric sphincter The stomach is a collapsible, pouch-like structure about 10 inches long and capable of holding 2 to 4 quarts. Attached to the lower end of the esophagus, the stomach lies immediately inferior to the diaphragm and extends to the duodenal portion of the small intestine. The stomach lies in the left upper quadrant of the abdominal cavity. The lateral surface of the stomach is called the greater curvature; the medial surface, the lesser curvature. The lesser omentum layer of the peritoneum extends around the stomach, and the greater omentum is found along the greater curvature of the stomach. The interior of the stomach is lined with rows of folds or wrinkles, called rugae. The stomach has four main regions: 1. Cardia: immediately distal to the gastroesophageal junction of the stomach and esophagus. 2. Fundus: enlarged portion distal to the cardia, lying above and to the left of the gastro-esophageal opening. 3. Body: the middle or main portion of the stomach, distal to the fundus and tapering in size. 4. Pylorus: the lower portion, between the body and the gastroduodenal junction. The stomach has three layers of smooth muscle -- the outer longitudinal, the middle circular, and the inner oblique muscles. 1. The maximum capacity of the stomach is about 3 to 4 liters. 2. The stomach receives blood from all three branches of the celiac artery. The left gastric artery supplies the lesser curvature of the fundus and the body of the stomach. The right gastric artery is a loop that supplies the lesser curvature and then forms an anastomosis with the left gastric artery. The left and right gastro-omental arteries supply the greater curvature. The mucosa of the stomach contains many gastric glands in the lamina propria: • Parietal (oxyntic) cells: located in fimdus and body; secrete HCL • Zymogenic (chief) cells: located in fundus and body; secrete pepsinogen • Enteroendocrine cells: present throughout the stomach; produce gastrin

Which of the following muscles of the anterior abdominal wall, when present, • External oblique • Internal oblique • Transversus • Rectus abdominis • Pyramidalis

Pyramidalis 1. As the spermatic cord (or round ligament of the uterus) passes under the Notes lower border of the internal oblique, the spermatic cord carries with it some of the muscle fibers that are called the cremaster muscle. 2. The posterior abdominal muscles include psoas major and minor (innervated by the lumbar plexus), quadratus lumborum (innervated by the lumbar plexus), and the iliacus (innervated by the femoral nerve).

All of the muscles of the quadriceps group serve to extend or straighten theN knee. Which one also flexes the thigh on the pelvis? • Rectus femoris • Vastus lateralis • Vastus intermedius • Vastus medius

Rectus femoris The thigh has two distinct muscle compartments (anterior and posterior) that are separated by con-nective tissue (deep fascia). Arising from the upper two-thirds of the femur, the quadriceps femoris muscle forms the major muscle mass of the front and outer side of the thigh (anterior compartment) covering most of the front and sides of the femur. The quadriceps femoris has four parts -- (all innervated by femoral nerve) • Rectus femoris: extends or straightens the knee and also flexes the thigh on the pelvis • Vastus lateralis } • Vastus intermedius } All extend or straighten the knee • Vastus medialis } The leg is divided into three compartments, with the anterior compartment containing the muscles that move the foot upward (dorsiflex the ankle). The lateral compartment contains the fibularis longus and fibularis brevis muscles, which are responsible for turning the sole of the foot outward (eversion). The posterior compartment of the leg contains the plantar flexors. The hamstring muscles lie in the posterior compartment of the thigh. The hamstring muscle group consists of three muscles: • Biceps femoris } The hamstring muscles function to extend the hip joint and flex the knee • Semitendinosus } joint. All are innervated by the tibial nerve, except the short head of the • Semimembranosus } biceps femoris, which is innervated by the common fibular nerve. The posterior compartment of the calf region contains numerous muscles, divided into two groups: superficial and deep. The superficial group contains the powerful gastrocnemius and soleus muscles, as well as the plantaris muscle, which are critical to pushing off from the ground (plantar flexion of the ankle joint) during walking, running, and jumping, and when standing on one's toes. The deep group contains the popliteus, flexor digitorum longus, flexor hallucis longus, and the tibialis posterior muscles. The largest of these, flexor hallucis longus, is critical for pushing off from the big toe during walking. Note: All of the muscles of the posterior compartment (superficial and deep) of the calf region are innervated by the tibial nerve.

The cartilage in the second branchial arch is called: • Meckel's cartilage • Reichert's cartilage • Thyroid cartilage • Cricoid cartilage

Reichert's cartilage Each paired branchial arch has its own developing cartilage, nerve, vascular, and muscular components within each mesodermal core. These elements are of neural crest origin. Derivatives of the branchial arch cartilages: • First arch cartilage (Meckel's cartilage) -- is closely related to the developing middle ear; becomes ossified to form the malleus and incus of the middle ear, sphenomandibular ligament, and portions of the sphenoid bone. Note: Most of this cartilage disappears as the bony mandible forms by intramembran¬ous ossification lateral to and in close association with it, yet only some of Meckel's cartilage makes a contribution to it. Its fate is said to be dissolution with minor contributions to ossification. • Second arch cartilage (Reichert's cartilage) -- is also closely related to the developing middle ear; becomes ossified to form the stapes of the middle ear, the styloid process of the temporal bone, the stylohyoid ligament, the lesser cornu of the hyoid bone, and the upper portion of the body of hyoid bone. • Third arch cartilage (unnamed cartilage) -- ossifies to form part of the hyoid bone. • Fourth through sixth arch cartilages (unnamed cartilage) -- fuse to foini the laryngeal cartilages.

Which of the following refers to the sarcoplasmic reticulum present in skeletal muscle? • Releases and stores phosphate ions during muscle contraction and relaxation • Releases and stores glucose during muscle contraction and relaxation • Releases and stores calcium ions during muscle contraction and relaxation

Releases and stores calcium ions during muscle contraction and relaxation It is a network of tubules and sacs in skeletal muscles. This network is analogous, but not identical, to the smooth endoplasmic reticulum of other cells. Remember: The endoplasmic reticulum is an extensive network of membrane-enclosed tubules in the cytoplasm of cells. This organelle is classified as granular or rough surfaced when ribosomes are attached to the surface of the membrane and as granular or smooth surfaced when ribosomes are absent. The structure functions in the synthesis of proteins and lipids and in the transport of these metabolites within the cell. The cytoplasm of muscle cells is called sarcoplasm. The sarcoplasm of each skeletal muscle fiber contains many parallel, thread-like structures called myofibrils. Each myofibril is composed of smaller strands called myofilaments that contain the contractile proteins, actin and myosin. The regular spatial organization of the contractile proteins within the myofibrils forms the cross banding. A network of membranous channels, called the sarcoplasmic reticulum, extends throughout the sarcoplasm. Note: It is mainly a great increase in the numbers of additional myofibrils (which is caused by progressively greater numbers of both actin and myosin filaments in the myofibrils) that causes muscle fibers to hypertrophy. Important: The number of muscle fibers does not increase; the size of each fiber increases.

The two terminal branches of the external carotid artery are the

Remember: The two terminal branches of the external carotid artery are the superficial temporal artery and the maxillary artery.

Which of the following is produced in reaction to various stimuli such as attrition, caries, or a restorative dental procedure? • Primary dentin • Secondary dentin • Reparative dentin • Mantle dentin

Reparative dentin Reparative dentin or tertiary dentin is dentin formed very rapidly in localized regions in response to a localized injury to exposed dentin. The injury could be caries, cavity preparation, attrition, or recession. Odontoblasts in the area of the affected tubules might die because of the injury, but neighboring undifferentiated mesenchymal cells of the pulp move and become odontoblasts. Tertiary dentin tries to seal off the injured area, thus the term reparative dentin. Primary dentin is the dentin formed in a tooth before the completion of the apical foramen of the root. Primary dentin is characterized by a regular pattern of tubules. Secondary dentin is the dentin that is formed after completion of the apical foramen. Secondary dentin is formed at a slower rate than primary dentin and is less mineralized. Secondary dentin is a regular and somewhat uniform layer of dentin around the pulp cavity. Secondary dentin is made by the odontoblastic layer that lines the dentin-pulp interface. Note: The junction between primary and secondary dentin is characterized by a sharp change in the direction of dentinal tubules. When dentin is damaged, usually by the chronic injury of caries, odontoblastic processes die or retract, leaving empty dentinal tubules. Areas with empty dentinal tubules are called dead tracts and appear as dark areas in ground sections of tooth. With time, these dead tracts can become completely filled with mineral. This region is called blind tracts and appears white in sections of ground tooth. A certain type of tertiary dentin called sclerotic dentin fills the blind tracts. The adaptive advantage of blind tracts is the sealing off of the dentinal tubules to prevent bacteria from entering the pulp cavity. Clinically, this sclerotic dentin appears dark, smooth, and shiny.

Emphysema is a pulmonary disease of the lung characterized by destruction of the supporting structures of the alveoli. This leads to increased elasticity of lung tissue and a pathologic increase in the size of the air spaces. What final division of the bronchioles within the respiratory tree contains alveoli and first permits gaseous exchange with the blood?

Respiratory bronchioles

Which layer of the dermis contains blood vessels, nerves, and other cells?) • Papillary layer • Reticular layer

Reticular layer The dermis is the thicker portion of the skin. The dermis is composed of connective tis-sue with collagenous and elastic fibers for toughness. The dermis develops from embry-onic mesoderm and contains blood vessels, nerves, glands, and hair follicles. The dermis is a strong, stretchable layer that essentially holds the body together. The dermis has two main regions: 1. Papillary layer -- thin and less fibrous; has projections (papillae) that extend up toward the epidermal layer. This layer contains the blood vessels that supply the overlying epidermis. The layer contains fibroblasts, mast cells, and macrophages. 2. Reticular layer -- thick and fibrous, and is continuous with the hypodermis. Blood vessels from the hypodermis pass through this layer. It contains more reticular fibers and fewer cells than the papillary layer. Characteristics of the subdermis (hypodermis) that connects the dermis with the under-lying fascia of muscles: • Composed primarily of loose (areolar) connective tissue • Major site of fat deposition (50% of body fat) • Has good blood supply

The pectinate muscles are prominent ridges of the atrial myocardium located on the inner surfaces of much of the: • Right atrium • Right ventricle • Left atrium • Left ventricle

Right atrium The pectinate muscles are prominent ridges of atrial myocardium located on the inner surfaces of much of the right atrium and of both auricles (which are small conical pouches projecting from the upper anterior portion of each atrium). The crista terminalis is a vertical muscular ridge that runs along the right atrial wall from the opening of the superior vena cava to the inferior vena cava. The crista terminalis provides the origin for the pectinate muscles. Note: The crista terminalis represents the junction between the sinus venosus and the heart in the developing embryo. It is represented on the external surface of the heart by a vertical groove called the sulcus terminalis. Important: The SA node is located in the crista terminalis near the opening of the superior vena cava. Remember: Papillary muscles are cone-shaped muscles that terminate in the tendinous cords (chordae tendineae) that attach to the cusps of the atrioventricular valves (tricuspid and mitral valve). Papillary muscles are found only in the ventricles of the heart. The papillary muscles do not help the valves to close. Instead, these muscles prevent the cusps from being everted (or being blown out) back into the atrium during ventricular contraction.

The coronary sinus receives most of the venous blood from the heart and empties into the: • Right ventricle • Left ventricle • Right atrium • Left atrium

Right atrium When viewed from the back (posterior view), the most obvious structure lying in the coronary sulcus is the coronary sinus. This sinus receives most of the venous blood from the heart and empties into the right atrium. Its tributaries are the small cardiac vein, middle cardiac vein, and the greater cardiac vein. There is a small vein that arises along the left side of the left atrium just beneath the lower left pulmonary artery (called the oblique vein). This vein is a rem¬nant of the embryonic left superior vena cava. • The great cardiac vein: opens into the left extremity of the coronary sinus. This vein re¬ceives tributaries from the left atrium and both ventricles: one, the left marginal vein, is of considerable size, and ascends along the left margin of the heart. • The small cardiac vein: opens into the right extremity of the coronary sinus. This vein receives blood from the back of the right atrium and ventricle; the right marginal vein as¬cends along the right margin of the heart and joins the small cardiac vein in the coronary sinus, or opens directly into the right atrium. • The middle cardiac vein: ends in the coronary sinus near its right extremity. • The oblique vein: ends in the coronary sinus near its left extremity; this vein is contin¬uous above with the ligament of the left vena cava. The following cardiac veins do not end in the coronary sinus: • The anterior cardiac veins: comprising three or four small vessels which collect blood from the front of the right ventricle and open into the right atrium; the right marginal vein frequently opens into the right atrium, and is therefore sometimes regarded as belonging to this group. • The smallest cardiac veins: consisting of a number of minute veins which arise in the muscular wall of the heart,; the majority open into the atria, but a few end in the ventricles. Note: The anterior interventricular artery (left anterior descending artery), a branch of the left coronary artery, accompanies the great cardiac vein. The posterior (or descending) in¬terventricular artery, a branch of the right coronary artery, accompanies the middle car¬diac vein.

Right hepatic artery -- to right lobe of liver.

Right hepatic artery -- to right lobe of liver. cystic artery -- arises from right hepatic artery to supply the gallbladder. Left hepatic artery -- to left lobe of liver. right gastric artery -- arises from the hepatic artery at the upper border of the pylorus to supply the lesser curvature of stomach. gastroduodenal artery -- large branch of hepatic artery that supplies the pancreas and duodenum - right gastroepiploic artery: supplies greater curvature of the stomach. - superior pancreaticoduodenal artery: supplies the upper half of the duodenum

right lung and left lung:compare and contrast

Right lung:Has three lobes (superior, middle, and inferior) and three secondary (lobar) bronchi, Contains ten bronchial segments (corresponding to the tertiary bronchi), Usually receives one bronchial artery, Has a slightly larger capacity than the left lung Left lung:Has two lobes (superior and inferior) and two secondary (lobar) bronchi, Contains eight bronchial segments (corresponding to the tertiary bronchi), Contains a cardiac notch (on its superior lobe), which is an indentation providing room for the heart, Usually receives two bronchial arteries, Contains a lingula, which is a tongue-shaped portion of its superior lobe that corresponds to the middle lobe of the right lung Each lung is enclosed in a double-layered pleural sac. One layer is called the visceral pleura; the other is called the parietal pleura. Between the two layers is the pleural cavity, which is filled with serous fluid.

In which phase of the interphase does the DNA replicate in preparation for mitosis? • G1 phase • S phase • G2 phase • M phase

S phase The cell cycle consists of interphase (including growth and synthesis) and mitosis. • Growth is the increase in cellular mass as the result of metabolism. • Synthesis is the replication of DNA in preparation for mitosis. • Mitosis is the splitting of the nucleus and cytoplasm that results in two diploid cells being formed. The cell cycle can be further divided into: • Interphase: the interval between successive cell divisions during which the cell is metabol¬izing and the chromosomes are directing RNA synthesis. It includes: 1. Gi phase -- the first growth phase 2. S phase -- DNA synthesis 3. G2 phase -- the second growth phase • M phase: mitosis (also called karyokinesis) is the division of the nuclear parts of a cell to form two diploid daughter cells. Cytokinesis is the division of the cytoplasm, which accompanies mitosis.

The functional unit of a skeletal muscle is a: • Fiber • Sarcolemma • Myofibril • Filament • Sarcomere

Sarcomere Each skeletal muscle fiber is surrounded by a membrane, the sarcolemma. In the muscle fiber's cytoplasm (sarcoplasm) are tiny myofibrils, arranged lengthwise. Each myofibril consists of two types of finer fibers called filaments (thick myosin filaments and thin actin filaments). The filaments are stacked in compartments called sarcomeres, the functional units of skeletal muscle. During muscle contraction, the sarcomere shortens when thick and thin filaments slide over each other. The striated pattern that is so characteristic of skeletal muscle directly results from the structure of the contractile units of the muscle. Each fiber of the muscle is striated and made up of many myofibrils, which are also striated in the same pattern of alternating dark and light bands called the A bands and I bands, respectively. In the center of each A band is a lighter zone called the H zone; in the center of each I band is a dark, thin line called the Z line. The portion of a myofibril between two Z lines constitutes a single contractile unit termed a sarcomere. Each sarcomere is composed of two sets of protein filaments. The thick myosin filaments are located in the A band. The thin actin filaments are located primarily in the I bands but extend into the A bands. The overlap of the actin and myosin filaments causes the dark coloration of the A bands; actin's absence from the center of the A bands results in the lighter H zone of each A band.

A 14-year-old female patient presents to the physician with hyperpigmented lesions (cafe-au-lait spots), hamartomas of the iris (Lisch nodules), and auxiliary freckling (Crowe's sign). The patient had previously been diagnosed with neurofibromatosis, but is now complaining of generalized pain and tingling. The physician discovers multiple neurolemmomas, classifying the disease as a form of neurofibromatosis. Neurolemmomas are a sarcoma of which cells that are responsible for myelin formation in the peripheral nervous system? • Astrocyte • Oligodendrocyte • Schwann cell • Microglial cell • Satellite cell

Schwann cell -- also called neurolemmocyte or neurolemma cell Schwann cells in the peripheral nervous system serve as supportive, nutritive, and service facilities for neurons. The gaps in the myelin sheath that occur between adjacent Schwann cells are called nodes of Ranvier, and serve as points along the neuron for generating a signal. Signals jumping from node to node travel hundreds of times faster than signals traveling along the surface of the axon (known as saltatory conduction). This allows your brain to communicate with your toes in a few thousandths of a second. Note: There are no Schwann cells in the CNS (central nervous system); the myelin sheath (in the CNS) is formed by the processes of the oligodendrocytes. Remember: The neural crest is a band of neuroectodermal cells that lie dorsolateral to the developing spinal cord, where they separate into clusters of cells (neural crest cells) that develop into dorsal root ganglion cells, autonomic ganglion cells, chromaffm cells of the adrenal medulla, neurolemma cells (Schwann cells), integumentary pigment cells (melanocytes), and the meningeal covering of the brain and spinal cord. Important: Microglial cells are the resident immune cells of the central nervous system. Their function resembles that of tissue macrophages.

The small, pea-shaped pituitary gland (hypophysis) is located on the inferio surface of the brain. This gland is positioned in the: • Infratemporal fossa of the sphenoid bone • Sella turcica of the sphenoid bone • Crista galli of the ethmoid bone • Cribriform plate of the ethmoid bone

Sella turcica of the sphenoid bone The sella turcica (literally Turkish saddle) is a saddle-shaped depression in the sphenoid bone at the base of the skull. The seat of the saddle is known as the hypophyseal fossa, which holds the pituitary gland (hypophysis cerebri). Located anteriorly to the hypophy¬seal fossa is the tuberculum sellae. Completing the formation of the saddle anteriorly is the dorsum sellae. The dorsum sellae is terminated laterally by the posterior clinoid processes. 1. The crista galli is a sharp upward projection of the ethmoid bone in the mid-line, for the attachment of the falx cerebri. 2. The cribriform plate consists of perforated areas on either side of the crista galli. It transmits olfactory nerve bundles. 3. The infratemporal fossa lies inferior to the temporal fossa and the infratem¬poral crest on the greater wing of the sphenoid bone. 4. The floor of the sella turcica is also the roof of the sphenoid sinus. Important points to remember concerning the pituitary gland: 1. Blood supply is from the right and left superior hypophyseal arteries and from the right and left inferior hypophyseal arteries, which are branches of the internal carotid artery. These form the rich vascular hypophyseal portal system. 2. The anterior pituitary or adenohypophysis is a classical gland composed predom¬inantly of cells that secrete protein hormones. 3. The posterior pituitary or neurohypophysis is not really an organ but an extension of the hypothalamus. The posterior pituitary is composed largely of the axons of hy¬pothalamic neurons that extend downward as a large bundle behind the anterior pitu¬itary. The posterior pituitary also forms the so-called pituitary stalk, which appears to suspend the anterior gland from the hypothalamus.

A pathologist receives a salivary tissue biopsy of what the dentist believes is pleomorphic adenoma. However, the dentist forgot to mention the site of the biopsy. The pathologist identifies certain histological structures that would indicate that this sample is not from the parotid gland. What structures can be seen in histologic examination of the submandibular and sublingual glands but not in the adult parotid gland? • Myoepithelial cells • Serous cells • Intercalated ducts • Serous demilunes • Striated ducts

Serous demilunes Important: Secretory cells are found in a group, or acinus (plural, acini), which resem¬bles a cluster of grapes. There are three forms of acini, serous, mucous, and mixed. • Mixed acini: these glands have both serous and mucous cells. - The mucous cells form tubules, but their ends are capped by serous cells that secrete between the mucous cells' intercellular space. These serous caps on mucous cells are called serous demilunes. • Approximately 10% of submandibular glands contain serous demilunes, but these glands are predominantly serous acini, which constitute 90% of the gland. • The sublingual gland contains serous demilunes amid its predominant mucous cell population. Serous cells are present exclusively on demilunes of mucous tubules. Note: The key point is that the parotid gland and the von Ebner's glands are purely serous and do not contain any mucous or mixed acini. These demilune cells secrete mucus that contains the enzyme lysozyme that degrades the cell walls of bacteria. In this way, lysozyme confers antimicrobial activity to mucus. Remember: All of the major salivary glands (parotid, submandibular, and sublingual) are classified as compound tubuloalveolar glands. This means that their ducts branch repeatedly (compound) and their secretory portions are tubular and composed of small sacs called alveoli or acini.

Which cell, known as the "mother cell," is a part of the seminiferous tubule and secretes hormones and proteins that facilitate spermatogenesis? • Interstitial cells • Endothelial cells • Sertoli cells • Clara cells

Sertoli cells

The main function of cementum is to provide rough surface anchorage for attachment of: • Transseptal fibers • Sharpey's fibers • Oblique fibers • Alveolar crest fibers

Sharpey's fibers Cementum is composed of a mineralized fibrous matrix and cells (cementocytes). The fibrous matrix consists of both Sharpey's fibers and intrinsic nonperiosteal fibers. Sharpey's fibers are the terminal portions of the principal fibers of the PDL (alveolodental ligament) that are each partially inserted into the outer part of the cem-entum at 90 degrees, or a right angle, to the cemental surface, as well as the alveolar bone on their other end. Remember: Cementum is the bone-like mineralized tissue covering the anatomical roots of teeth. The two basic types are acellular and cellular. Other functions of cementum include the following: • Compensates for the loss of tooth surface due to occlusal wear by apical deposit-ion of cementum throughout life • Protects the root surface from resorption during vertical eruption and tooth movement - 1. Histologically, cementum differs from enamel in the following ways: Notes • Cementum has collagen fibers • Cementum has cellular components in the mature tissue 2. Cementoid is the peripheral layer of developing cementum that is laid down by cementoblasts undergoing cementogenesis. Cementoid is uncalci¬fied or immature. 3. When the cementoid reaches the full thickness needed, the cementoid sur-rounding the cementocytes becomes calcified or matured and is then consid-ered cementum. 4. Cementocytes are cementoblasts entrapped by the cementum they produce.

Which venous sinus of the cranial cavity turns forward and then downward through the posterior part of the jugular foramen, to become continuous with the superior bulb of the internal jugular vein? • Sigmoid sinus • Superior sagittal sinus • Transverse sinus • Straight sinus

Sigmoid sinus The dural venous sinuses are spaces between the endosteal and meningeal layers of the dura. These si-nuses contain venous blood that originates for the most part from the brain or cranial cavity. The sinuses contain an endothelial lining that is continuous into the veins that are connected to the sinuses. There are no valves in the sinuses or in the veins that are connected to the sinuses. The vast majority of the venous blood in the sinuses drains from the cranium via the internal jugular vein. • The superior sagittal sinus is found in the upper border of the falx cerebri and begins at the crista galli. The superior sagittal sinus is fed by blood from the superior cerebral veins and ends at the confluence of sinuses near the internal occipital protuberance. • The inferior sagittal sinus is located in the lower free border of the falx cerebri between the two cere-bral hemispheres. This sinus begins anteriorly and ends with its junction with the straight sinus. • The straight sinus originates with the union of the great cerebral vein and inferior sagittal sinus. The straight sinus runs posteriorly in the junction between the falx cerebelli and tentorium cerebelli to become continuous with one of the transverse sinuses (most commonly the left). • The cavernous sinuses are found on either side of the body of the sphenoid bone in middle cranial fos¬sae. These sinuses receive blood from the sphenoparietal sinuses that are located underneath the free edges of the lesser wings of the sphenoid bone. Blood also drains into the cavernous sinuses via the su-perior and inferior ophthalmic veins. The cavernous sinuses drain posteriorly through the superior and inferior petrosal sinuses and inferiorly through the pterygoid plexus of veins. • The superior petrosal sinuses are located in the edge of the tentorium cerebelli on the ridge of the petrous part of the temporal bone. These sinuses drain into the transverse sinuses. • The inferior petrosal sinuses are found at the base of the petrous part of the temporal bone in the pos-terior cranial fossae where these sinuses empty into the internal jugular vein. • The basilar sinus interconnects with inferior petrosal sinuses and the internal vertebral plexus. • The transverse sinuses extend laterally from the confluence of sinuses in the tentorium cerebelli. The transverse sinuses travel ventrally to become the sigmoid sinuses of each side. • The sigmoid sinuses bend into an S-shaped curve and continue into the internal jugular vein through the jugular foramen. • The occipital sinus is located in the posterior attached border of the falx cerebelli. This sinus commu-nicates superiorly with the confluence of sinuses and inferiorly with the internal vertebral plexus.

permeability of sinusoids

Sinusoids are highly permeable, having larger inter-cellular clefts, fewer tight junctions, and discontinuous endothelial cells (meaning that the individual endothelial cells do not overlap as in capillaries and are spread out). The level of permeability is such as to allow small- and medium-sized proteins such as albumin to enter and leave the bloodstream. Some spaces are large enough for blood cells to pass. Oxygen, carbon dioxide, nutrients, proteins, and wastes are exchanged through the thin walls of the sinusoids.

The dental lamina, a thickening of the oral epithelium that produces the swellings of the enamel organs, is first seen histologically: • Second week in utero • Sixth week in utero • Tenth week in utero • Fourth month in utero

Sixth week in utero By the third week after conception, the primitive mouth (stomodeum) has formed. Over the next few weeks, the tongue, jaws, and palate develop. During the sixth week, formation of the teeth commences, and by eight weeks, all of the primary (deciduous) incisors, canines, and molars are discernable. Tooth development appears to be initiated by the mesenchyme's inductive influence on the overlying ectoderm. Early in the sixth week, there appears to be a thickening of the oral epithelium (which is a derivative of the surface ectoderm). These thickenings or U-shaped bands are called the dental lamina and follow the curve of the primitive jaws. At certain points on the dental lamina, the ectodermal cells proliferate and produce swellings that become the enamel organ. Inside the depression of the enamel organ, an area of condensed mesenchyme becomes the dental papilla. Surrounding both the enamel organ and dental papilla is a capsule-like structure of mesenchyme called the dental sac. Note: The enamel organ separates from the dental lamina after the first layer of dentin is deposited. Remember: Each tooth is the product of two tissues that interact during tooth development, the oral epithelium and the underlying ectomesenchyme. The oral epithelium grows down into the underlying ectomesenchyme and forms small areas of condensed mesenchyme, which become tooth germs.

lenticulostriate arteries

Small, deep penetrating arteries known as the lenticulostriate arteries branch from the middle cerebral artery. These arteries are often called the "arteries of stroke" because they are often involved in a stroke (also called a cerebrovascular accident).

At a picnic, the kids all decide to hang upside down on the monkey bars. One daring kid decides that he will try to eat a grape while hanging upside down and finds that he has no trouble doing this. Involuntary movements of internal organs such as peristalsis are produced by which type of muscle tissue? • Voluntary muscle tissue • Smooth muscle tissue • Striated muscle tissue • Skeletal muscle tissue • Cardiac muscle tissue

Smooth muscle tissue Smooth muscle tissue is located throughout the body, particularly within the tunica (walls) of hollow internal organs. The smooth muscle fibers are elongated and spindle-shaped with a single nucleus. The myofibrils lack transverse striations. They are responsible for involuntary movements of internal organs (e.g., peristalsis). Types of smooth muscle: • Single-unit: have numerous gap junctions (electrical synapses) between adjacent fibers. These fibers contract spontaneously without nerve signals Examples include: the muscular tunica of the GI tract, uterus, ureters, and arterioles. • Multi-unit: lacks gap junctions and the individual fibers are autonomically inner¬vated. Examples include the ciliary muscle and the smooth muscle of the iris, ductus deferens, and arteries Skeletal muscle tissue attaches to the skeleton and is responsible for voluntary body movement. It consists of many elongated, cylindrical cells, which are multinucleated and have distinct transverse striations consisting primarily of actin and myosin proteins. Remember: Each skeletal muscle fiber is innervated by an axon of a motor neuron at a motor end plate (which is a large and complex terminal formation by which an axon of a motor neuron establishes synaptic contact with a skeletal muscle).

All of the following are lined by keratinized mucosa EXCEPT one. Which one is the EXCEPTION? • Dorsum of the tongue • Soft palate • Hard palate • Gingival tissues

Soft palate The oral mucosa is a mucous membrane that covers all structures inside the oral cavity except the teeth. The oral mucosa varies in color from pink to brownish purple depending on an individual's skin color. The structure of the oral mucosa varies depending on its location in the oral cavity and the function of that area. Remember: 1. The crevicular (sulcular) epithelium and gingival col are nonkeratinized gingival tissues. 2. The lining of a healthy sulcus is composed of nonkeratinized epithelial tissues with no rete pegs. The pres¬ence of rete pegs is indicative of the presence of inflammation. 3. The junction of the lining mucosa with the masticatory mucosa is the mucogingival junction. The oral mucosa is composed of two layers: 1. Stratified squamous epithelium, which may be nonkeratinized, parakeratinized, or orthokeratin-ized depending upon its location. 2. Lamina propria (connective tissue), which supports the epithelium. Subdivided into two layers (papillary and dense). It may be attached to the periosteum of the alveolar bone or interposed over the submucosa (the submucosa contains glands, blood vessels, and nerves). Note: A basement membrane is located between the oral epithelium and the connective tissue. The basement membrane is composed of two layers -- basal and reticular lamina.

carry impulses to skeletal muscle? • Somatic sensory (afferent) fibers • Visceral sensory (afferent) fibers • Somatic motor (efferent) fibers • Visceral motor (efferent) fibers

Somatic motor (efferent) fibers Functionally, the fibers of peripheral nerves may either be somatic or visceral and also either sensory (afferent) or motor (efferent). There are four types of fibers: 1. Somatic sensory (afferent) fibers carry impulses from cutaneous and proprioceptive receptors. 2. Visceral sensory (afferent) fibers carry impulses from the viscera. 3. Somatic motor (efferent) fibers carry impulses to skeletal muscle. 4. Visceral motor (efferent) fibers carry impulses to smooth and cardiac muscle and to glands. Somatic motor vs. visceral motor: • Somatic motor neurons are directed from cortical levels to skeletal muscles and are voluntary. • Visceral motor neurons are directed from the hypothalamus and midbrain and are voluntary, but have input from the cortex and thalamus. • Somatic lower motor neurons are in the ventral horn of gray matter and the neurotransmitter at skeletal muscle is acetylcholine. • Visceral motor neurons come from cranial nerves or the intermediolateral gray horn, involve two neurons, and the neurotransmitter is either acetylcholine or norepinephrine at either cardiac muscle, smooth muscle, or glands.

Comparison of the Somatic and Autonomic

Somatic: Effectors= Skeletal muscle Control= Usually voluntary Efferent pathways= One nerve fiber from CNS to effector; no ganglia Neurotransmitters= Acetylcholine (Ach) Effect on target cells= Always excitable Effect of denervation= Flaccid paralysis Autonomic: Effectors=Glands, smooth muscle, cardiac muscle Control=Usually involuntary Efferent pathways=Two nerve fibers from CNS to effector; synapse at a ganglion Neurotransmitters=Ach and norepinephrine (NE) Effect on target cells=Excitatory or inhibitory Effect of denervation=Denervation hypersensitivity

A prosthodontist designs his maxillary removable complete and partial dentures to engage the hamular notch behind the maxillary tuberosities. The hamulus is a small slender hook, which extends from the medial pterygoid plate. The medial pterygoid plate is a component of the pterygoid process, which is a component of which bone?

Sphenoid bone: The left and right pterygoid processes project downward from near the junction of each of the greater wings within the body of the sphenoid bone. These processes run along the posterior portion of the nasal passage toward the palate. Each process consists of a medial and a lateral pterygoid plate. The lateral pterygoid plate provides the origin for both lateral and medial pterygoid muscles. The plate also forms the medial wall of the infratemporal fossa. The medial pterygoid plate forms the posterior limit of the lateral wall of the nasal cavity. The medial plate ends inferiorly as a hamulus, a small, slender hook that acts as a pulley for the tensor veli palatini tendon to change its direction of pull from vertical to horizontal, thereby tens'ng the soft palate.

As a result of curiosity, a 2-year-old boy decides to stick a sharp object up his nose and causes a nosebleed (epistaxis) of the anteroinferior portion of the nasal septum. This bleeding involves the septal branches of the:

Sphenopalatine and facial arteries: The arterial blood supply to the nasal cavity is derived mainly from branches of the maxillary artery. The most important branch is the sphenopalatine artery, which enters the nasal cavity through the sphenopalatine foramen. The sphenopalatine artery anastomoses with the septal branch of the superior labial branch of the facial artery in the region of the vestibule, which is a very common site of bleeding from the nose. Remember: The sphenopalatine artery is the terminal branch of the maxillary artery.

Spongy (cancellous) bone

Spongy (cancellous) bone is lighter and less dense than compact bone. Spongy bone consists of plates (trabeculae) and bars of bone adjacent to small, irregular cavities that contain red bone marrow. The canaliculi connect to the adjacent cavities, instead of a central haversian canal, to receive their blood supply. It may appear that the trabeculae are arranged in a haphazard manner, but they are organized to provide maximum strength similar to braces that are used to support a building. The trabeculae of spongy bone follow the lines of stress and can realign if the direction of stress changes. (****from here on i just copied and pasted)

Summary of Different Types of Epithelium Cells and Function (s) Simple Stratified Specialized: • Transitional • Pseudostratified

Squamous Cuboidal Columnar Squamous Cuboidal Columnar Varies between cuboidal and squamous Columnar cells atop one another with nuclei located at two or more levels within cells Diffusion and filtration Secretion or absorption Absorption and secretion Protection, prevents water loss Protection and secretion Protection Specialized to undergo distension May have cilia that function to move fluids past the cells

Which muscle functions to turn the head side to side? • Digastric • Mylohyoid • Sternocleidomastoid • Omohyoid

Sternocleidomastoid

Which muscle separates the anterior cervical triangle from the posterior cervical triangle? • Trapezius • Omohyoid • Mylohyoid • Sternocleidomastoid

Sternocleidomastoid The neck can be further divided into triangles, the two most important being the anterior and posterior cervical triangles. The anatomic borders of the anterior cervical triangle are the medial portion of the sternocleidomastoid muscle, the lower border of the mandible, and the midline of the neck. Important structures within this triangle are the carotid arteries and jugular veins, thyroid gland, esophagus, trachea, larynx, and vagus nerve. The posterior cervical triangle's borders are the lateral edge of the sternocleidomastoid muscle, trapezius, and clavicle. Important structures within this region are the subclavian artery and vein, suprascapular artery, and brachial plexus. The posterior triangle of the neck can further be subdivided into: 1. Occipital triangle lying above the inferior belly of the omohyoid muscle. Contents includes the spinal accessory nerve (CN XI) and the superficial cervical cutaneous branches of the cervical plexus. Part of the occipital and parts of the transverse cervical and suprascapular arteries are also found in the occipital triangle. 2. Subclavian triangle lying inferior to this muscle. Contents includes the superior, middle, and inferior trunks of the brachial plexus, suprascapular nerve, and artery, the subclavian artery and vein as well as the external jugular vein. Important: Muscles that usually appear in the floor of the posterior triangle include the medius scalene, splenius capitis, levator scapulae, and the anterior belly of the omohyoid.

Which of the following epithelium functions in the secretion and propulsion of mucous by cilia? • Simple epithelium • Stratified epithelium • Pseudostratified epithelium

Stratified epithelium • Simple epithelium has only a single layer of cells, all contacting the basal lamina. • Stratified epithelium has two or more layers, with only the deeper layer contact-ing the basal lamina. • Pseudostratified epithelium appears multilayered, but is actually only a single layer with all of the cells touching the basal lamina. The positioning of the nuclei within the individual columnar cells causes this illusion.

The oral epithelium is covered by a layer of: • Stratified cuboidal epithelium • Stratified squamous epithelium • Stratified columnar epithelium • Pseudostratified columnar epithelium

Stratified squamous epithelium This stratified squamous epithelium acts as a mechanical barrier and protects the underlying tissues. There are three types found within the oral cavity: 1. Nonkeratinized (most common) -- selective barrier, acts as a cushion. Cells do not contain keratin. Is associated with lining mucosa (i.e., buccal and labial mucosa, mucosa lining the floor of the mouth, ventral surface of the tongue, and the soft palate) 2. Orthokeratinized (least common) -- associated with masticatory mucosa (i.e., hard palate and the attached gingiva, also the lingual papillae on the dorsal surface of the tongue) 3. Parakeratinized -- associated with masticatory mucosa (i.e., attached gingiva, in higher levels than orthokeratinization, and the tongue's dorsal surface) Note: The main difference between parakeratinized epithelium and orthokeratinized epithelium is in the cells of the keratin layer. In parakeratinized epithelium, the superficial layer is still being shed or lost, but these cells of the keratin layer contain not only keratin but also nuclei, unlike those of orthokeratinized epithelium. Other cell types (other than keratinocytes) found in the oral epithelium: • Epithelial cells -- form a cohesive sheet that resists physical forces and serves as a barrier to infection • Melanocytes -- synthesize melanin • Langerhans cells -- antigen presenting cells, part of immune system • Granstein cells -- antigen presenting cells, part of immune system • Merkel cells -- associated with sensory nerve endings • White blood cells -- PMNs are the most commonly occurring All forms of epithelium (whether associated with lining, masticatory, or specialized mucosa) have a lamina propria (connective tissue proper) deep to the basement membrane. It supports the epithelium and is subdivided into two layers (papillary and dense). It may be attached to the periosteum of the alveolar bone or interposed over the submucosa (the submucosa contains glands, blood vessels, and nerves). Note Abasement membrane is located between the oral epithelium and the connective tissue. The basement membrane is composed of two layers -- basal and reticular lamina.

1UponC returning from a two-week trip to Mayan ruins in Mexico, a Harvarc archeologist keeps getting compliments on his tan. Melanin is produced ,..,,., by melanocytes, which are located in which layer of the epidermis? i • Stratum corneum • Stratum lucidum • Stratum granulosum • Stratum spinosum of stratum germinativum • Stratum basale of stratum genninativum

Stratum basale of stratum germinativum The epidermis is the outer, thinner portion of the skin. The epidermis is avascular. It devel-ops from embryonic ectoderm. The epidermis consists of four layers. From innermost to out¬ermost, they are: 1. Stratum germinativum -- contains the only cells of the epidermis that receive nutrition; cells are constantly undergoing division and being pushed up to the body surface. Two sub¬divisions include: • Stratum basale -- deepest layer; cuboidal to columnar cells; site of continuous cellu-lar reproduction. Melanocytes, which produce melanin, are located here • Stratum spinosum -- next deepest layer; contains cells called Langerhans cells; con¬tains nerve cells *** The two subdivisions together are sometimes called the malpighian layer. 2. Stratum granulosum -- three to five rows of flat cells; site of keratin production 3. Stratum lucidum -- only in the thick skin of the palms and soles; consists of clear, flat, dead cells 4. Stratum corneum -- outermost layer of epidermis; 25 to 30 rows of flat, dead cells filled with keratin; continuously shed and replaced Note: The bottom layer of the stratum germinativum, the stratum basale, has cells that are shaped like columns. In this layer, the cells divide and push already formed cells into higher layers. As the cells move into the higher layers, the cells flatten and eventually die. The top layer of the epidermis, the stratum corneum, is made of dead, flat skin cells that shed about every two weeks. Important: There are three types of specialized cells in the epidermis. The melanocyte pro-duces pigment (melanin), the Langerhans cell is the frontline defense of the immune system in the skin, and the keratinocyte produces keratin (a protective protein). They are the most common cell type in the epidermis of the skin. Note: Tonofibrils (fibrillar structural proteins) and desmosomes are especially well developed in keratinocytes.

The four distinct layers of the enamel organ include all of the following EXCEPT one. Which one is the EXCEPTION? • Outer enamel epithelium • Inner enamel epithelium • Stratum granulosum • Stratum intermedium • Stellate reticulum

Stratum granulosum Four layers of the enamel organ: 1. Outer enamel epithelium (OEE) -- the outer cellular layer of the enamel organ (very thin). This layer outlines the shape of the future developing enamel organ. 2. Inner enamel epithelium (IEE) -- the innermost cellular layer of the enamel organ (very thin). The cells in this layer will become ameloblasts and produce enamel. This layer is essential for the initiation of dentin formation once enamel is formed. 3. Stratum intermedium -- this area lies immediately lateral to the inner enamel epithelium (thicker than both the OEE and IEE). This layer of cells seems to be essential to enamel formation (prepares nutrients for• the ameloblasts of the IEE). 4. Stellate reticulum -- this area is the central core and fills the bulk of the enamel organ. This layer contains a lot of intercellular fluid (mucus-type fluid rich in album¬in) that is lost just before enamel deposition. Remember: After enamel formation is completed, all of the above structures of the enamel organ become one and form the reduced enamel epithelium. This is important in the formation of the dentogingival junction, which is an area where the enamel and epithelium come together as the tooth erupts into the mouth. This forms the initial junctional epithelium (or epithelial attachment), which later migrates down the tooth to assume its normal position.

IA 23-year-old male medical student is experiencing diplopia and goes to get an MRI done. The scan shows non-descript periventricular lesions, and so a spinal tap is done to determine whether the patient has multiple sclerosis. Which space is entered when a spinal tap is performed? • Conus medullaris • Subarachnoid space • Arachnid space • Central canal

Subarachnoid space The spinal cord ends in the adult around LI (1,1 to L2). The dura and arachnoid, however, continue down to level S2, where the arachnoid fuses with the filum terminale. Thus, a needle inserted between the spines at L2 and L3 will enter the subarachnoid space, which is filled with cerebrospinal fluid, without injuring the spinal cord. Cerebrospinal fluid (CSF) is a colorless, thin fluid found in the ventricles of the brain, the subarachnoid space, and the central canal of the spinal cord. CSF is produced mainly by a structure called the choroid plexus in the lateral, third and fourth ventricles. CSF escapes the ventricular system of the brain through the three foramina of the fourth ventricle and so enters the subarachnoid space. CSF now circulates both upward over the surfaces of the cerebral hemispheres and downward around the spinal cord. The subarachnoid space extends down as far as the second sacral vertebra. Eventually, the fluid enters the bloodstream by passing into the arachnoid villi and diffusing through their walls. 1. The choroid plexuses regulate the intraventricular pressure by secretion and absorption of cerebrospinal fluid. 2. The cerebrospinal fluid, along with the bony and ligamentous walls of the vertebral canal, protects the spinal cord from injury. 3. Ependymal cells are cells that make up the lining membrane of the ventricles of the brain and of the central canal of the spinal cord. They are also present in the choroid plexus of the central nervous system and participate in the production of cerebrospinal fluid.

Which salivary gland can have either numerous small ducts that open onto the floor of the mouth or a single main excretory duct (Barthohn's duct) that empties at the sublingual caruncle? • Submandibular gland • Parotid gland • Sublingual gland

Sublingual gland The sublingual gland is the smallest of the three main salivary glands. It contains both serous and mucous (with serous demilunes) acini, the latter predominating. It is located beneath the oral mucosa in the floor of the mouth between the mandible on one side and the genioglossus and hyoglossus muscles on the other side. The sublingual gland sits on the mylohyoid muscle. Unlike the submandibular gland, which drains via one large duct, the sublingual gland drains via approximately 12-20 small ducts (Rivinus 's ducts) along the sublingual fold along the floor of the mouth. The sublingual gland is innervated by parasympathetic secretomotor fibers from superior salivary nucleus of the facial nerve. The nerve fibers pass to the submandibular ganglion via the chorda tympani nerve and the lingual nerve. Postganglionic parasympathetic fibers pass to the gland via the lingual nerve. Postganglionic sympathetic fibers reach the gland as a plexus of nerves around the facial and lingual arteries. The blood supply is from the sublingual branch of the lingual artery and from the submental branch of the facial artery. Important: • The veins drain into the facial and lingual veins. The lymph vessels drain into the submandibular and deep cervical lymph nodes • Sometimes the numerous sublingual ducts (12 to 20 in number) join to form a single main excretory duct (Bartholin's duct) that usually empties into the submandibular duct Note: Von Ebner's glands are located around the circumvallate papilla of the tongue. Their main function is to rinse the food away from the papilla after the food has been tasted by the taste buds. These glands are purely serous.

A patient in the dental clinic states in his medical history that he has heart disease and occasionally takes nitroglycerin for his pain. During treatment, the patient clutches his chest and frantically points to his jacket pocket. The dentist obtains the nitroglycerin bottle from his jacket, removes one tablet, and places it: • On the soft palate • On the gingiva • Sublingually • On the buccal tissue

Sublingually In general, the permeabilities of the oral mucosa decrease in the order of sublingual greater than buccal and buccal greater than palatal. This rank order is based on the relative thickness and degree of keratinization of those tissues, with the sublingual mucosa being relatively thin and nonkeratinized, the buccal thicker and nonkeratinized, and the palatal intermediate in thickness but keratinized. Important point: The oral cavity is highly acceptable for systemic drug delivery. The mucosa is relatively permeable with a rich blood supply, and the virtual lack of Langerhans cells makes the mucosa tolerant of potential allergens. This route also bypasses the first pass effect and avoids pre-systemic elimination in the GI tract. Example: Nitroglycerin tablets are given sublingually for rapid absorption. Remember: The oral mucosa is composed of an outermost layer of stratified squamous epithelium. Below this lies a basement membrane, a lamina propria (connective tissue proper) followed in most cases by the submucosa as the innermost layer. The composition of the epithelium varies depending on the site in the oral cavity. The mucosa of areas subject to mechanical stress (the gingiva and hard palate) is keratinized (specifically, orthokeratinized). The mucosa of the soft palate, the sublingual, and the buccal regions, however, is not keratinized. Note: Alveolar mucosa is very similar to sublingual mucosa in that it, too, appears red due to the numerous blood vessels and the thin epithelial covering.

When walking to his car late at night, a professor hears footsteps behind him. His sympathetic response (fright-or-flight) results in dilated pupils, a dry mouth, and constriction of blood vessels in his face that makes him look ashen. Which ganglia, located at the level of the C1-C2 vertebrae, house the cell bodies that cause the sympathetic response in the head? • Superior cervical ganglion • Middle cervical ganglion • Inferior cervical ganglion • Ganglion impar

Superior cervical ganglion Paravertebral sympathetic ganglia lie on each side of the vertebrae and are connected to form the sympathetic chain or trunk. There are usually 21 or 23 pairs of these gan¬glia: 3 in the cervical region, 12 in the thoracic region, 4 in the lumbar region, 4 in the sacral region, and a single, unpaired ganglion lying in front of the coccyx called the gan¬glion impar. Three cervical ganglia: 1. Superior cervical ganglion: the uppermost and largest, stretching from the level of Cl to the level of C2 or C3. This ganglion lies between the internal carotid artery and the internal jugular vein. The superior cervical ganglion innervates viscera of the head. 2. Middle cervical ganglion: small, located at the level of the cricoid cartilage. This ganglion is related to the loop of the inferior thyroid artery. Innervates viscera of the neck, thorax (i. e., the bronchi and heart), and upper limb. 3. Inferior cervical ganglion: occurs at the C7 vertebral level. Most commonly is fused to the first thoracic sympathetic ganglion to form a stellate ganglion. Innerv¬ates viscera of the neck, thorax (i.e., the bronchi and heart), and upper limb. Important: • The gray rami connect the sympathetic trunk to every spinal nerve. The white rami are limited to the spinal cord segments between T1 and L2 • The cell bodies of the visceral efferent fibers in visceral branches of the sympathetic trunk are located in the intermediolateral cell column (or lateral horn) of the spinal cord; the cell bodies of visceral afferent fibers are located in the dorsal root ganglia

On a patient's panoramic radiograph, the dentist notices a small, well-defined radiolucency that sits inferior to the mandibular canal. The dentist performs a sialogram that rules out a true cyst and makes the working diagnosis a static bone cavity (Stafne bone cyst). Which of the following salivary glands creates the depression in bone that radiographically gives the above appearance? • Sublingual gland • Von Ebner's glands • Submandibular gland • Parotid gland

Submandibular gland The submandibular gland weighs half the weight of the parotid. This gland is often referred to as the submaxillary gland. This gland lies in the submandibular triangle formed by the anterior and posterior bellies of the digastric muscle and the inferior margin of the mandible. The gland is positioned medial and inferior to the mandibular ramus partly superior and partly inferior to the base of the posterior half of the mandible. The gland forms a 'C' around the anterior margin of the mylohyoid muscle, which divides the submandibular gland into a superficial and deep lobe. The deep lobe comprises the majority of the gland. The glandular elements are a mixture of serous (mostly) and mucous acini with some serous demilunes. As is the case with the parotid gland, the submandibular gland is invested in its own capsule, which is also continuous with the superficial layer of deep cervical fascia. Important: The marginal mandibular branch of the facial nerve courses superficial to the submandibular gland and deep to the platysma. The submandibular duct (Wharton's duct) arises from the deep portion of the gland and crosses the lingual nerve in the region of the sublingual gland to terminate on the sublingual caruncle (papilla) adjacent to the base of the sublingual frenulum. When the sublingual duct (Bartholin's duct) is present, it usually terminates on or near the submandibular caruncle also. Important: The lingual nerve wraps around Wharton's duct, starting lateral and ending medial to the duct, while CN XII (the hypoglossal nerve) parallels the submandibular duct, running just inferior to it. Blood supply: The blood supply is from the sublingual branch of the lingual artery and from the submental branch of the facial artery. The facial artery forms a groove in the deep part of the gland, and then curves up around the inferior margin of the mandible to supply the face. The veins drain into the facial and lingual veins. The lymph vessels drain into the submandibular and deep cervical lymph nodes. Innervation: Parasympathetic secretomotor fibers from the superior salivary nucleus of the facial nerve. The nerve fibers pass to the submandibular ganglion via the chorda tympani nerve and the lingual nerve. Postganglionic parasympathetic fibers pass to the gland via the lingual nerve. Postganglionic sympathetic fibers reach the gland as a plexus of nerves around the facial and lingual arteries.

Stroke warning signs

Sudden weakness, paralysis, or numbness of the face, arm, and leg on one or both sides of the body. Loss of speech or difficulty speaking or understanding speech. Dimness or loss of vision, particularly in only one eye. Unexplained dizziness (especially when associated with other neurologic symptoms), unsteadiness, and sudden falls. Sudden severe headache and loss of consciousness

Which group of structures empties directly into the right atrium? • Superior vena cava, coronary sinus, and hemiazygos vein • Coronary sinus and pulmonary vein • Pulmonary and bronchial veins • Superior and inferior venae cavae and coronary sinus • Coronary sinus and azygos vein

Superior and inferior venae cavae and coronary sinus The coronary sinus lies in the posterior part of the coronary sulcus (atrioventricular groove) and opens in the right atrium between the opening of the inferior vena cava and the right atrioventricular orifice, its opening being guarded by a semilunar valve (Thebe¬sian valve). The superior vena cava opens into the upper part of the right atrium. The superior vena cava returns the blood from the upper half of the body. The inferior vena cava (larger than the superior vena cava) opens into the lower part of the right atrium. The inferior vena cava returns the blood from the lower half of the body. Flow of the blood through the heart: 1. Entering the right atrium are the coronary sinus and the superior and inferior venae cavae carrying deoxygenated blood from the systemic circuit. 2. Upon contraction of the right atrium, blood passes through the right AV valve to the right ventricle. 3. Upon contraction of the right ventricle, blood leaves to pass to the right and left lungs via the pulmonary arteries. 4. Blood gases are exchanged in the lung, and oxygenated blood returns via pulmon¬ary veins to the left atrium. 5. Upon contraction of the left atrium, blood passes through the left AV valve to the left ventricle. 6. Upon contraction of the left ventricle, oxygenated blood passes through the aortic valve to the systemic circuit via the aorta and its branches.

At what level does the common carotid artery bifurcate?

Superior border of the thyroid cartilage

The internal thoracic artery ends in the sixth intercostal space by dividing into the:

Superior epigastric and musculophrenic arteries: The internal thoracic artery supplies the anterior wall of the body from the clavicle to the umbilicus. It is a branch of the first part of the subclavian artery in the neck. This artery descends vertically on the pleura behind the costal cartilages, just lateral to the sternum, and ends in the sixth intercostal space by dividing into the superior epigastric and musculophrenic arteries.

superior, middle, and inferior meatus

Superior meatus: lies below and lateral to the superior concha. The superior meatus receives the openings of the posterior ethmoidal sinuses.Middle meatus: lies below and lateral to the middle concha. The middle meatus receives the openings of the frontal, maxillary, anterior, and middle ethmoidal sinuses. The middle ethmoidal sinuses drain onto the ethmoidal bulla (rounded prominence on the lateral wall of the middle meatus). The anterior ethmoidal sinuses drain into the infundibulum (funnel-like structure that empties into a groove called the hiatus semilunaris on the lateral wall of the middle meatus). The frontal sinuses drain into the infundibulum or directly into the middle meatus. The maxillary sinus drains directly into the hiatus semilunaris; its opening (ostium) is located near the top of the sinus. Inferior meatus: lies below and lateral to the inferior conchae. It receives the opening of the nasolacrimal duct. The nasolacrimal duct drains lacrimal fluid from the surface of the eye into the meatus for evaporation during respiration.

The portal vein is about 2 inches long and is formed behind the neck of the pancreas by the union of the: • Left gastric and the left colic veins • Appendicular and the inferior mesenteric veins • Superior mesenteric and the splenic veins • Right gastric and the right colic veins

Superior mesenteric and the splenic veins The portal vein (most commonly referred to as the hepatic portal vein) is a major vein that drains blood from the abdominal part of the gastrointestinal tract from the lower third of the esophagus to halfway down the anal canal; the portal vein also drains blood from the spleen, pancreas, and gallbladder. The portal vein enters the liver and breaks up into sinusoids, from which blood passes into the hepatic veins that join the inferior vena cava. The portal vein is formed behind the neck of the pancreas by the union of the superior mesenteric and the splenic veins. The portal vein ascends to the right, behind the first part of the duodenum, and enters the lesser omentum. The portal vein then runs upward in front of the opening into the lesser sac to the porta hepatis, where it divides into right and left branches, before entering the liver. Almost all of the blood coming from the digestive system drains into a special venous circulation called the portal circulation. This is because it contains all the nutrients and toxins that have been absorbed along the digestive tract from ingested food. Before these absorbed substances can go into the systemic circulation, the portal circulation must be filtered first to remove or "detoxify" them. This filtering and detoxification are functions of the liver. The tributaries of the portal vein are the: • Splenic vein: joins the superior mesenteric vein to form the portal vein • Inferior mesenteric vein: is joined by the splenic vein, which drains the accessory di-gestive organs of the pancreas and spleen, as well as part of the stomach • Superior mesenteric vein: joins the splenic vein to form the portal vein • Gastric vein, which drains the upper part of the stomach, and the cystic veins, which drain the gallbladder, also drain into the portal vein Note: Once blood delivered by the hepatic portal system has filtered through the liver, the blood is returned to the heart via the inferior vena cava. Important: The portal vein carries twice as much blood as the hepatic artery.

The cranial nerves that supply motor innervation to muscles that move the eyeball all enter the orbit through the:

Superior orbital fissure

The upper half of the duodenum is supplied by the (blank), a branch O1N the gastroduodenal artery. The lower half of the duodenum is supplied by the (blank), a branch of the superior mesenteric artery.

Superior pancreaticoduodenal artery; inferior pancreaticoduodenal artery

Branches of the external carotid:

Superior thyroid artery - supplies thyroid gland, gives off a branch to the sternocleidomastoid muscle and superior laryngeal artery. Lingual artery - supplies the tongue. Facial artery - supplies the face, including lips and the submandibular gland. Ascending pharyngeal artery - supplies the pharyngeal wall. Occipital artery - supplies the pharynx and suboccipital triangle. Posterior auricular artery - supplies back of the scalp. Maxillary artery - terminal branch of external carotid, it gives off branches to the mandible, and the middle meningeal artery before passing through the pterygomaxillary fissure to enter the pterygopalatine fossa to supply the maxilla. Superficial temporal artery - terminal branch of external carotid, supplies skin over frontal and temporal regions of scalp Important: The external carotid artery and its branches supply the muscles of the neck and face, thyroid gland, salivary glands, scalp, tongue, jaws, and teeth.

The great veins of the neck are all derivatives from the: • External jugular vein • Internal jugular vein • Retromandibular vein • Superior vena cava

Superior vena cava The two largest veins in the body are the superior and inferior vena cavae, which drain into the heart from above and below, respectively. The great veins of the neck are all derivatives from the superior vena cava. The superior vena cava is a large, yet short vein that carries deoxygenated blood from the upper half of the body to the heart's right atrium. The superior vena cava is formed by the left and right brachiocephalic veins. There are three main veins in the neck, the external, anterior, and internal jugular veins. • The external jugular vein originates from just behind the mandible's angle, and is formed by the unification of the posterior auricular vein and the posterior division of the retro- mandibular vein. Note: The retromandibular vein itself is formed within the parotid gland. This vein's formation arises from the unification of the superficial temporal and the maxil-lary veins. • The internal jugular vein, which drains the head and brain, joins the subclavian vein to form the brachiocephalic vein. The left and right brachiocephalic veins join to form the superior vena cava, which drains into the heart. • The anterior jugular vein arises below the chin from the veins draining the chin and lower lip, passes down the front of the neck superficially, and terminates in the external jugular vein at the lateral border of the anterior scalene muscle. 1. The brachial, basilic, and cephalic veins drain the upper limbs; these veins drain into the axillary vein, which becomes the subclavian vein. 2. The azygos vein, which drains the thoracic cavity, joins the superior vena cava, just before it enters the heart. 3. The femoral vein drains the lower limb, becoming the external iliac vein as it enters the trunk, where the vein is joined by the internal iliac vein from the pelvis to become the common iliac vein. 4. The two common iliac veins join to form the inferior vena cava, which passes up the posterior abdominal wall, where the inferior vena cava is joined by veins from the kidneys, gonads, liver, and back region. The inferior vena cava passes through the diaphragm and enters the heart.

Functions of the skeletal system:

Support: skeleton forms a rigid framework to which are attached the softer tissues and organs of the body. Protection: the skull and vertebral column enclose the CNS; the rib cage protects the heart, lungs, great vessels, liver, and spleen; and the pelvic cavity supports the pelvic viscera.Body movement: bones serve as anchoring attachments for most skeletal muscles. In this capacity, the bones act as levers with the joints functioning as pivots when muscles contract to cause body movement.Hemopoiesis: the red bone marrow of an adult produces red blood cells, white blood cells, and platelets.Mineral storage: the inorganic matrix of bone is composed primarily of the minerals calcium and phosphorus. These minerals give bone its rigidity and account for approximately two-thirds of the weight of bone. About 95% of the calcium and 90% of the phosphorus within the body are deposited in the bones and teeth.Bone exists in two forms: Compact (appears as a solid mass) and spongy or cancellous bone, which consists of a branching network of trabeculae.

Muscles of the Anterior Abdominal Wall Action: External oblique Internal oblique Transversus Rectus abdominis Pyramidalis (if present)

Supports abdominal contents; compresses abdomi- nal contents; assists in flexing and rotation of trunk. Assists in forced expiration, micturition, defecation, parturition, and vomiting Same as above I Compresses abdominal contents Compresses abdominal contents and flexes vertebral column; accessory muscle of expiration Tenses the linea alba

The principal types of nerves found in the dental pulp are: • Parasympathetic and efferent fibers • Sympathetic and afferent fibers • Sympathetic and efferent fibers • Parasympathetic and afferent fibers

Sympathetic and afferent fibers The sensory nerve fibers in the dental pulp originate in the trigeminal ganglion and are categorized, from smallest to largest diameter, into C-fibers, A-delta, and some A-beta fibers. On the other hand, postganglionic sympathetic nerve fibers originate in the supe¬rior cervical ganglion. A-delta fibers are myelinated low-threshold mechano-receptors and are responsible for the so-called "first pain signal". C-fibers are unmyelinated, high-threshold fibers. They are termed poly-nodal because they respond to several types of stimuli such as mechanical, chemical, or thermal stimulation of the pulp. C-fibers most likely mediate the sensation of "second pain". Note: The pulp contains both myelinated and unmyelinated nerve fibers. Tooth pulp consists of a loose type of connective tissue. Its main components are thin collagen fibers arranged asymmetrically plus a ground substance containing gly- cosaminoglycans. Tooth pulp is a highly innervated and vascularized tissue. Numerous fibroblasts are present. Surrounding the pulp and separating it from the dentin are the odontoblasts. Important: Pain originates in the pulp due to free nerve endings (afferent fibers), which are the only type of nerve ending found in the pulp and are specific receptors for pain. Re¬gardless of the source of stimulation (heat, cold, pressure), the only response will be pain. Note: Vasomotor sympathetic fibers are thought to end on blood vessels. Functions of the pulp: 1. Nutritive -- very rich blood supply that surrounds the odontoblasts. 2. Formative -- peripheral layer of pulp cells gives rise to the odontoblasts that form dentin. 3. Sensory -- free nerve endings that make contact with the odontoblasts.

Comparison of Sympathetic and Parasympathetic Origin in CNS Location of ganglia Fiber lengths Neuronal divergence Effects on system

Sympathetic: Thoracolumbar (T1-L2) Paravertebral ganglia adjacent to spinal column and prevertebral ganglia anterior to it Short preganglionic Long postganglionic Extensive (about 1:17) Often widespread and general Parasympathetic: Craniosacral (CN 111,VII, IX, and X; S2-S4) Terminal ganglia near or within target organs Long preganglionic Short postganglionic Minimal (about 1:2) More local and specific

The glossopharyngeal nerve (CN IX) innervates all of the following EXCEPT one. Which one is the EXCEPTION? • Stylopharyngeus muscle • Parotid gland • Taste to the anterior two-thirds of the tongue • Taste to the posterior one-third of the tongue • Carotid sinus

Taste to the anterior two-thirds of the tongue The glossopharyngeal nerve innervates the stylopharyngeus muscle (via the muscular branch). It is the only muscle that is supplied by this nerve. This muscle is a landmark for locating the glossopharyngeal nerve because as the nerve enters the pharyngeal wall, it curves posteriorly around the lateral margin of this muscle. In addition to the somatic motor innervation of the stylopharyngeus, the glossoph¬aryngeal nerve supplies preganglionic parasympathetic motor fibers to the otic ganglion. These fibers synapse with the postganglionic fibers in the ganglion to supply the parotid gland. The preganglionic nerves leave the glossopharyngeal nerve as the tympanic nerve, which enters the middle ear cavity and participates in the formation of the tympanic plexus. The tympanic nerve reforms as the lesser petrosal nerve, leaves the cranial cavity through the foramen ovale, and enters the otic ganglion. Postganglionics are carried by the auriculotemporal nerve (V-3) to the parotid. Visceral sensory branches of the glossopharyngeal nerve: • Lingual branches -- are two in number; one supplies the vallate papillae and the mucous membrane covering the base of the tongue; the other supplies the mucous membrane and follicular glands of the posterior one-third of the tongue, and communicates with the lingual nerve *** Also carries some secretomotor fibers to the glands • Pharyngeal -- distributed to the mucous membrane of the pharynx. Is the sensory limb of the gag reflex • Carotid sinus nerve -- to carotid sinus (baroreceptor) and carotid body (chemo-receptor) Remember: The lingual nerve (branch of V3) descends deep to the lateral pterygoid muscle, where the lingual nerve is joined by the chorda tympani (branch of the facial nerve), which conveys the preganglionic parasympathetic fibers to the submandibular ganglion and taste fibers from the anterior two-thirds of the tongue.

A 17-year-old male patient who has no history of vaccinations comes into the physician's office with bilateral swelling of the parotid glands, fever, headache, and orchitis. Orchitis is the painful swelling of what organ, which produces male gametes? j • Prostate gland • Ductus deferens • Testes • Scrotum • Penis

Testes

In which cellular component are glycoproteins assembled for extracellular use? • The Golgi apparatus • The endoplasmic reticulum • The nucleus • The nucleolus

The Golgi apparatus The function of the Golgi apparatus is two-fold: First, the modification of lipids and pro¬teins; Second, the storage and packaging of materials that will be exported from the cell. The Golgi apparatus is often called the "shipping department" of the cell. The vesicles that pinch off from the Golgi apparatus move to the cell membrane, and the material in the vesicle is released to the outside of the cell. Some of these pinched-off vesicles also become lysosomes. Important: The Golgi apparatus is where glycoproteins are assem¬bled for extracellular use. The Golgi apparatus (sometimes called the Golgi body) is similar to endoplasmic retic-ulum (ER). It is composed of flat, membranous sacs, or cisternae, arranged in stacks like pancakes. These stacks have two poles -- the cis face, which receives materials for pro¬cessing, and the trans face, through which substances are released for transport to other parts of the cell. 1. These cisternae are located between the nucleus and the secretory surface of Notei- a cell. 2. They package, store, and modify products that are secreted from the cell. 3. Procollagen filaments are formed here from amino cells. Lysosomes are cytoplasmic membrane-bound vesicles that contain a wide variety of gly¬coprotein hydrolytic enzymes that serve to digest and destroy exogenous material, such as bacteria.

Aorta

The aorta is the main trunk of a series of vessels that convey the oxygenated blood to the tissues of the body for their nutrition. The aorta commences at the upper part of the left ventricle, and after ascending for a short distance, arches backward and to the left side, over the root of the left lung; the aorta then descends within the thorax on the left side of the vertebral column, passes into the abdominal cavity through the aortic opening of the diaphragm in front of the twelfth thoracic vertebra. The aorta descends behind the peritoneum on the anterior surface of the bodies of the lumbar vertebrae. At the level of the fourth lumbar vertebra, the aorta divides into the two common iliac arteries. Note: The characteristic feature of the aorta is that it contains a lot of elastic fibers in its tunica media (middle layer of blood vessel wall). Anatomically, the aorta is traditionally divided into the ascending aorta, the aortic arch, and the descending aorta. The descending aorta is, in turn, subdivided into the thoracic aorta (that descends within the chest) and the abdominal aorta (that descends within the abdomen).

The left subclavian, left carotid, and brachiocephalic artery are branches of the:

The arch of the aorta is a continuation of the ascending aorta. The aortic arch lies behind the manubrium sterni and arches upward, backward, and to the left in front of the trachea (its main direction is backward). It then passes downward to the left of the trachea, and at the level of the sternal angle become continuous with the descending aorta. Branches include: The brachiocephalic artery is an extremely short artery and is the first branch from the aortic arch. This artery passes upward and to the right of the trachea and divides into the right common carotid and right subclavian arteries behind the right stemoclavicular joint. Remember: There are two (right and left) brachiocephalic veins but only one brachiocephalic artery. The left common carotid artery arises from the convex surface of the aortic arch on the left side of the brachiocephalic artery. The left common carotid artery runs upward and to the left of the trachea and enters the neck behind the left sternoclavicular joint. The left subclavian artery arises from the aortic arch behind the left common carotid artery. The left subclavian artery runs upward along the left side of the trachea and the esophagus to enter the root of the neck. This artery arches over the apex of the left lung.Important: The upper limbs are supplied by the subclavian arteries (both right and left). The head and neck are supplied by the right and left common carotid arteries.

blood supply of small intestine

The arterial supply of the jejunum and ileum is from branches of the superior mesenteric artery. The intestinal branches arise from the left side of the artery and run in the mesentery to reach the gut. They anastomose with one another to form a series of arcades. The lowest part of the ileum is also supplied by the ileocolic artery.

The bone of the alveolar process exists only to support the

The bone of the alveolar process exists only to support the teeth. If a tooth fails to erupt, alveolar bone never forms in that area; and if a tooth is extracted, the alveolus resorbs after the extraction until finally the alveolar ridge completely atrophies. The position of the tooth, not the functional load placed on it, determines the shape of the alveolar ridge. Note: The long axes of the mandibular condyles intersect at the foramen magnum, which indicates that these axes are directed posteromedially.

carotid body

The carotid body lies posterior to the point of bifurcation of the common carotid artery. The carotid body is innervated by the glossopharyngeal and vagus nerves and is a chemoreceptor, being sensitive to excess carbon dioxide and reduced oxygen tension in the blood (this would produce a rise in blood pressure and heart rate).

carotid sinus

The carotid sinus is a dilated portion of the proximal part of the internal carotid artery, near the bifurcation of the common carotid artery. This is usually at the level of the superior border of the thyroid cartilage. Changes in blood pressure stimulate vagal nerve endings in the wall of the carotid sinus to send signals along the vagus nerve to slow the heart rate; this response is referred to as the carotid sinus reflex. Important: The carotid sinus is innervated by the carotid sinus branch of the glossopharyngeal nerve and by a branch of the vagus nerve.

The third ventricle of the brain communicates with the fourth ventricle by the) • The two foramina of Luschka • The interventricular foramen • The cerebral aqueduct • The foramen of Magendie

The cerebral aqueduct There are four ventricles in the brain. They connect with each other, the central canal of the spinal cord, and the subarachnoid space surrounding the brain and spinal cord. The ventricles contain cerebrospinal fluid, which acts as a shock absorber, cushioning the brain from me¬chanical forces. The right and left lateral ventricles are in the right and left cerebral hemispheres, respec¬tively. The ventricles communicate with the narrow third ventricle in the diencephalon through a small opening, the interventricular foramen (foramen of Monro). The third ven¬tricle is continuous with the fourth ventricle via the cerebral aqueduct (also called the aqueduct of Sylvius) that traverses the midbrain. The fourth ventricle is located dorsal to the pons and medulla, and ventral to the cerebellum. A single median aperture (foramen of Ma¬gendie) and a pair of lateral apertures (foramen of Luschka) provide communication between the fourth ventricle and the subarachnoid space. Cerebrospinal fluid is produced mainly by a structure called the choroid plexus in the lat¬eral, third and fourth ventricles. CSF flows from the lateral ventricle to the third ventricle through the interventricular foramen (also called the foramen of Monro). The third ventri¬cle and the fourth ventricle are connected to each other by the cerebral aqueduct (also called the aqueduct of Sylvius). CSF then flows into the subarachnoid space through the foramina of Luschka (there are two of these) and the foramen of Magendie (only one of these). Note: Absorption of the CSF into the bloodstream takes place in the superior sagittal sinus through structures called arachnoid villi. When the CSF pressure is greater than the venous pressure, CSF will flow into the bloodstream. However, the arachnoid villi act as "one way valves" -- if the CSF pressure is less than the venous pressure, the arachnoid villi will NOT let blood pass into the ventricular system.

The circle of Willis

The circle of Willis (also called the cerebral arterial circle) is formed by the posterior cerebral (branch of basilar artery), posterior communicating (branch of internal carotid), internal carotid, anterior cerebral, and anterior communicating (branch of internal carotid) arteries. This circle of Willis forms an important means of collateral circulation in the event of obstruction.

The common carotid artery

The common carotid artery is branchless and travels up the neck, lateral to the trachea and larynx, to the upper border of the thyroid cartilage. The common carotid artery travels in a sheath deep to the sternocleidomastoid muscle. This sheath also contains the internal jugular vein and the vagus nerve. The common carotid artery ends by dividing into the internal and external carotid arteries at about the level of the larynx.

tmj bio

The condyle of the mandible rests in the mandibular fossa (also called glenoid Notes fossa) of the temporal bone. The fossa articulates with the condyle of the mandible to form the TMJ. The articular eminence forms the anterior boundary of the fossa and helps maintain the mandible in position. This area is the functional and articular portion of the TMJ. Separating the mandibular fossa from the tympanic plate posteriorly is the squamotympanic fissure, through the medial end of which (petrotympanic fissure) the chorda tympani exits from the tympanic cavity. The concave area between the mandibular condyle and coronoid process is the mandibular notch (also known as the coronoid notch). The mandibular notch transmits arteries and nerves to the masseter muscle. Important: The posterior slope of this eminence is lined by fibrous connective tissue.

Other small arteries that supply blood to the nasal cavity include:

The descending palatine branch of the maxillary artery, The superior labial branch of the facial artery, The posterior ethmoidal branch and anterior ethmoidal branch of the ophthalmic artery

dorsal lingual artery

The dorsal lingual artery runs on the superficial surface of the tongue -- it is a branch of the lingual artery that delivers blood to the posterior superficial tongue. So, this artery must be the source of the hemorrhage.

A pancreatic cancer patient has a tumor that presses on the ampulla of Vater. This has been causing him GI problems because the tumor obstructs the common bile duct and the main excretory duct of the pancreas known as: • Wharton's duct • The duct of Wirsung • Bartholin's duct • Wolffian duct

The duct of Wirsung The pancreas is a retroperitoneal organ located posterior to the stomach on the posterior abdominal wall. The pancreas's large head is framed by the C-shaped loop of the duodenum, while the tail touches the spleen. The pancreas plays a role in both the digestive and endocrine systems. The pancreas is covered in a tissue capsule that partitions the gland into lobules. The endocrine function of the pancreas is concerned with both foodstuff release during fast¬ing and foodstuff storage after meals. The two pancreatic hormones responsible for these functions are glucagon and insulin, respectively. These two hormones are produced in spe¬cial cell types within many tiny spherical clumps of pancreatic tissue, which are known as the pancreatic islets or the islets of Langerhans. Within the islets of Langerhans, the alpha cells secrete glucagon, which elevates blood sugar; beta cells secrete insulin, which affects the metabolism of fats, proteins, and carbohydrates; and delta cells secrete somatostatin, which can inhibit the release of both glucagon and insulin. Two ducts that may be associated with the pancreas: 1. The main pancreatic duct (duct of Wirsung) -- begins at the tail and joins the common bile duct to form the hepatopancreatic ampulla (ampulla of Vater) before opening into the duodenum. This ampulla discharges bile and pancreatic enzymes into the descending portion (second part) of the duodenum. 2. The accessory pancreatic duct (Santorini's duct) -- when present opens separately into the duodenum. 1. Bartholin's duct is the major sublingual duct (when present) that drains the sublingual salivary gland and opens on the sublingual papilla in the floor of the mouth. 2. Wolffian duct (also called the mesonephric duct) is an embryonic duct that develops in the male into the deferent duct; in the female, it is obliterated.

A cementicle is a spherical, calcified body that lies in the periodontal ligament or fused to the cementum of a tooth. The remnants of the epithelial root sheath that then become calcified to form a cementicle are called: • Accessory root canals • The epithelial rests of Malassez • The dentinoenamel junction (DEJ) • The cementoenamel junction (CEJ

The epithelial rests of Malassez The epithelial rests of Malassez are remnants of Hertwig's epithelial root sheath and can be found as groups of epithelial cells in the periodontal ligament. Some rests degenerate; others become calcified (form cementicles). Remember: The purpose of Hertwig's epithelial root sheath is to shape of the root (or roots) and induce dentin formation (by stimulating the differentiation of odontoblasts) in the root area so that it is continuous with coronal dentin. After this root dentin is deposited, the cervical portion of the root sheath breaks down, and this new dentin comes in contact with the dental sac. This contact stimulates cells from the dental sac to differentiate into cells that will produce cementum, the PDL, and the alveolar bone proper. Important: The continuity of Hertwig's epithelial root sheath must be broken in order for cementum to be deposited during tooth development (cementogenesis). Hertwig's epithelial root sheath is characterized by: • The formation of cell rests (rests of Malassez) in the PDL when the sheaths funct-ions have been accomplished • The absence of a stellate reticulum and a stratum intermedium Remember: The structure responsible for root development is the cervical loop, which is the most cervical portion of the enamel organ.

ethmoid bone

The ethmoid bone is exceedingly light and spongy, and cubical in shape; this bone is situated at the anterior part of the base of the cranium, between the two orbits, at the roof of the nose, and contributes to each of these cavities. The ethmoid bone consists of four parts: a horizontal or cribriform plate, forming part of the base of the cranium; a perpendicular plate, constituting part of the nasal septum; and two lateral masses or labyrinths.

Facial Artery

The facial artery supplies blood to the face, tonsils, palate, labial glands, and muscles of the lips. The facial artery also supplies the submandibular gland, the ala and dorsum of the nose, and the muscles of facial expression. The facial artery originates in the external carotid artery and gives off branches that supply the neck and face.

The flat bones of the skull and face, the mandible, and the clavicle develop by

The flat bones of the skull and face, the mandible, and the clavicle develop by intramembranous ossification. It is so called because it takes place within membranes of connective tissue. The mandible and maxilla are formed this way. This process contributes to the growth of short bones and the thickening of long bones. This process involves the transformation of osteoblasts to osteocytes.Remember: Once bone is formed, it grows by appositional growth (growth by addition of new layers on those previously formed).

The major arteries that supply the head and neck are the

The major arteries that supply the head and neck are the common carotid and subclavian arteries. The origins from the heart of the common carotid and subclavian arteries that supply the head and neck are different for the right and left sides of the body. For the right side of the body, the common carotid and subclavian arteries are both branches from the brachiocephalic artery. The brachiocephalic artery is a direct branch of the aorta.

All of the following statements are true concerning the triangle of auscultation EXCEPT one. Which one is the EXCEPTION? • It is situated behind the scapula • It is bounded above by the trapezius muscle, below by the latissimus dorsi muscle, and laterally by the medial margin of the scapula • The floor of the triangle is partly formed by the sternocleidomastoid muscle • It is a space on the back where the relatively thin musculature allows for respiratory sounds to be heard more clearly with a stethoscope

The floor of the triangle is partly formed by the sternocleidomastoid muscle *** This is false; the floor is partly formed by the rhomboideus major muscle. For purposes of description, the neck is divided into anterior and posterior triangles by the sternocleidomastoid muscle; the anterior triangle lies in front of the muscle and the posterior triangle lies behind it. The anterior triangle is subdivided into smaller triangles by the anterior and posterior bellies of the digastric muscle and the superior belly of the omohyoid muscle. These smaller triangles include: Submental triangle: Boundaries: Anterior bellies of digastric and hyoid bone Floor: Mylohyoid Contents (main): Submental lymph nodes, floor of mouth Digastric (or submandibular) triangle: Boundaries: Anterior and posterior bellies of digastric and the lateral margin of the mandible Floor: Mylohyoid and hyoglossus Contents (main): Submandibular gland Carotid triangle: Boundaries: Sternocleidomastoid; posterior digastric and superior omohyoid Floor: Thyrohyoid, hyoglossus, and pharyngeal constrictors Contents (main): bifurcation of common carotid Muscular triangle: Boundaries: Superior omohyoid; sternocleidomastoid and anterior margin of neck Floor: Sternohyoid and sternothyroid Contents (main): Infrahyoid muscles, thyroid and parathyroid glands

Which of the following receives fibers from the motor, sensory, and parasympa- thetic components of the facial nerve and sends fibers that will innervate the lacrimal, submandibular, and sublingual glands? • Semilunar ganglion • Geniculate ganglion • The otic ganglion • The ciliary ganglion

The geniculate ganglion The geniculate ganglion is an L-shaped collection of fibers and sensory neurons of the facial nerve located in the facial canal of the head. The geniculate ganglion receives fibers from the motor, sen¬sory, and parasympathetic components of the facial nerve and sends fibers that will innervate the lacrimal glands, submandibular glands, sublingual glands, tongue (anterior two-thirds), palate, pharynx, external auditory meatus, stapedius, posterior belly of the digastric muscle, stylohyoid muscle, and muscles of facial expression. Sensory and parasympathetic inputs are carried into the geniculate ganglion via the nervus in¬termedius. Motor fibers are carried via the facial nerve proper. The greater petrosal nerve, which carries sensory fibers as well as preganglionic parasympathetic fibers, emerges from the ante¬rior aspect of the ganglion. Important branches of the intrapetrous part of the facial nerve: • The greater petrosal nerve arises from the facial nerve at the geniculate ganglion. The nerve contains preganglionic parasympathetic fibers that pass to the pterygopalatine ganglion and are there relayed through the zygomatic and lacrimal nerves to the lacrimal gland; other postgan¬glionic fibers pass through the nasal and palatine nerves to the glands of the mucous membrane of the nose and palate. The nerve also contains many taste fibers from the mucous membrane of the palate. The nerve emerges on the superior surface of the petrous part of the temporal bone and runs forward to enter the foramen lacerum. It is here joined by the deep petrosal nerve from the sympathetic plexus on the internal carotid artery and forms the nerve to the pterygoid canal. This passes forward and enters the pterygopalatine fossa, where it ends in the ptery-gopalatine ganglion. • The nerve to the stapedius arises from the facial nerve to supply the stapedius muscle. • The chorda tympani arises from the facial nerve just above the stylomastoid foramen. The nerve leaves the tympanic cavity through the petrotympanic fissure and enters the infratemporal fossa, where the nerve joins the lingual nerve. The chorda tympani contains many taste fibers from the mucous membrane covering the anterior two-thirds of the tongue, and the floor of the mouth. The nerve also contains preganglionic parasympathetic secretomotor fibers that reach the submandibular ganglion and are there relayed to the submandibular and sublingual salivary glands.

what arteries supply the hard and soft palate

The greater palatine artery supplies the mucosa of the hard palate posteri Notes or to the maxillary canine. Mucosa of the hard palate anterior to the maxillary canine is supplied by the nasopalatine artery. The soft palate and tonsils are supplied by the lesser palatine artery.

hepatic artery

The hepatic artery brings oxygenated blood to the liver, while the hepatic portal vein brings food-laden blood from the abdominal viscera. Note: The hepatic portal vein is formed by the union of the superior mesenteric vein and the splenic vein. Remember: All the blood supplied to the liver from the hepatic arteries and the portal vein eventually drains via the hepatic veins to the inferior vena cava. Important: The most unusual aspect of hepatic circulation is that all the blood supplied to the liver from the hepatic arteries and the portal vein empties into the same sinusoids (minute endothelial-lined passageways in the liver lobules), which therefore contain a mixture of arterial and venous blood. The sinusoids of each lobule empty into a common central vein. The common central vein of each lobule then empties into one of three hepatic veins. These veins all empty into the inferior vena cava, which transports the blood to the heart.

Superior orbital fissure

The superior orbital fissure is located posteriorly between the greater and lesser wings of the sphenoid bone. The superior orbital fissure communicates with the middle cranial fossa.

All of the following comparisons between the ileum and jejunum are correct EXCEPT one. Which one is the EXCEPTION? • The mesentery of the ileum contains more fat • The ileum has more plicae circulares (valves of Kerckring) and more villi • They are both suspended by mesentery • Less digestion and absorption of nutrients occur in the ileum

The ileum has more plicae circulares (valves of Kerckring) and more villi *** This is false; the jejunum has more plicae circulares (valves of Kerckring) and more villi. Note: The lower part of the ileum has no plicae circulares (valves of Kerckring). Comparison of the jejunum and ileum: Jejunum (middle portion of small intestine): extends from duodenum to the ileum 1. Thicker muscular wall for more active peristalsis. 2. Has a mucosal inner lining of greater diameter for absorption. 3. Has more (and larger) plicae circulares (valves of Kerckring) and more villi for greater absorption. Ileum (distal portion of the small intestine): extends from the jejunum to the cecum 1. More mesenteric fat. 2. More lymphoid tissue (Peyer's patches). 3. Blood supply is more complex. 4. More goblet cells, which secrete mucus. Remember: 1. Valves of Kerckring. The lining of the small intestine has permanent folds known as valves of Kerckring or plicae circulares. These are most prominent in the jejunum. These folds, seen macroscopically in transverse sections, consist of mucosa and submucosa. 2. Intestinal villi. These are finger-like projections into the lumen (consisting of surface epithelium and underlying lamina propria). *** The epithelium lining the lumen consists of a simple columnar epithelium with gob-let cells. The apical surface of the absorptive epithelial cells has a "brush border" (result-ing from an orderly arrangement of closely-packed microvilli, which may number several hundred per absorptive cell). The main function of the microvilli is to increase the surface area available for absorption.

inferior alveolar nerve

The inferior alveolar nerve (branch of V-3), artery, and vein travel through the mandibular foramen. At the mental foramen, the inferior alveolar nerve ends by dividing into (1) the mental nerve, which supplies the skin of the mental region and mucous membrane and (2) the incisive branch that supplies the pulp chambers of the anterior teeth and adjacent mucous membrane.

The internal carotid artery has no...

The internal carotid artery has no branches outside the skull and enters the skull through the carotid canal. Inside the skull, the internal carotid artery gives off the ophthalmic artery, which supplies the optic nerve, eye, orbit, and scalp. The artery terminates by passing through the cavernous sinus to join the circle of Willis and supply the brain.

The internal carotid

The internal carotid has no branches in the neck. The internal carotid'sbranches supply the structures inside the cranial cavity. The internal carotid gives rise to the ophthalmic artery, the major blood supply of the orbit and eye, that enters the orbit through the optic foramen (canal) with the optic nerve. The internal carotid ends by dividing into the anterior and middle cerebral arteries that contribute to the great cerebral circle (of Willis).

blood supply of large intestine

The large intestine extends from the ileum to the anus. The large intestine is divided into the cecum, the appendix, the ascending colon, the transverse colon, the descending colon, and the sigmoid colon. The blood supply to these areas is as follows: Cecum: the arterial blood supply is from the anterior and posterior cecal arteries, which are branches of the ileocolic artery, a branch of the superior mesenteric artery Appendix: the arterial supply is by means of the appendicular artery, a branch of the posterior cecal artery Ascending colon: the arterial blood supply is from the ileocolic and right colic branches of the superior mesenteric artery Transverse colon: the arterial blood supply of the proximal two-thirds is from the middle colic artery, a branch of the superior mesenteric artery. The distal third is supplied by the left colic artery, a branch of the inferior mesenteric artery Descending colon: the arterial blood supply is from the left colic and sigmoid branches of the inferior mesenteric artery Sigmoid colon: the arterial blood supply is from the sigmoid branches of the inferior mesenteric artery. Note: The arterial blood supply to the rectum is from the superior, middle, and inferior rectal arteries. The superior rectal artery is a direct continuation of the inferior mesenteric artery. The middle rectal artery is a small branch of the internal iliac artery. The inferior rectal artery is a branch of the internal pudendal artery in the perineum. The arterial blood supply to the anus (anal canal) is from the superior and inferior rectal arteries.

lingual artery

The lingual artery arises from the anterior surface of the external carotid artery, opposite the tip of the greater cornu of the hyoid bone. The lingual artery loops upward and then passes deep to the posterior border of the hyoglossus muscle to enter the sub-mandibular region. The loop is crossed superficially by the hypoglossal nerve. The loop supplies blood to the tongue, suprahyoid region, sublingual gland, palatine tonsils, and floor of the mouth. Important: In the oral region, the lingual artery usually is found between the hyoglossus and genioglossus muscles. Branches of the lingual artery include the suprahyoid, dorsal lingual, sublingual, and deep lingual branches.

lingula

The lingula is a tongue-shaped projection of bone that serves as the attachment for the sphenomandibular

During the fourth week of embryonic development, the first branchial arch divides to form: • The two medial nasal processes • The mandibular and maxillary process • The two lateral nasal processes • The lateral and medial nasal process

The mandibular and maxillary process — also called maxillary and mandibular prominences The branchial (pharyngeal) arches are stacked bilateral swellings of tissue that appear inferior to the stomodeum during the fourth week of embryonic development. These branchial arches are six pairs of U-shaped bars with a core mesenchyme formed by neural crest cells that migrate to the neck region. The branchial arches are covered externally by ectoderm and lined internally by endoderm. The ectoderm between the arches form clefts (grooves) called branchial (pharyngeal) clefts (grooves). The arches are bordered medially by the pharynx, which is lined by endoderm. Medially each of the branchial arches is separated by a pharyngeal pouch. These pouches approach the corresponding branchial cleft. The approximation of the ectoderm of the pharyngeal cleft with the endoderm of the pharyngeal pouch forms the pharyngeal membrane. The grooves and pouches are named (numbered) the same as the preceding arch. After formation of the stomodeum (the primitive mouth) but still within the fourth week, two bulges of tissue appear inferior to the primitive mouth, the two large mandibular processes of the first branchial arch. Important: The mandible forms as a result of the fusion of the these two large mandibu¬lar processes. Note: The mandibular symphysis is a faint ridge in the midline on the surface of the bony mandible where the mandible is formed by the fusion of the mandibular processes. The two smaller maxillary processes of the first branchial arch form the maxilla, the upper cheek regions, and most of the upper lip.

sphenopalatine artery and nasopalatine branch

The maxillary artery ends by becoming the sphenopalatine artery, which supplies the nasal cavity. The sphenopalatine artery gives rise to the posterior lateral nasal branches and septal branches, including a nasopalatine branch that accompanies the nasopalatine nerve through the incisive foramen on the maxilla.

The maxillary artery is one of the terminal arteries of the

The maxillary artery is one of the terminal arteries of the external carotid. The other terminal artery of the external carotid is the superficial temporal artery.

maxillary artery

The maxillary artery is the larger terminal branch of the external carotid artery. It begins at the neck of the mandibular condyle within the parotid gland. The maxillary artery runs between the mandible and the sphenomandibular ligament anteriorly and superiorly through the infratemporal fossa. After traversing the infratemporal fossa, the maxillary artery enters the pterygopalatine fossa. Within the infratemporal and pterygopalatine fossae, the maxillary artery gives off many branches.

middle cerebral artery

The middle cerebral artery is the largest branch of the internal carotid. The artery supplies a portion of the frontal lobe and the lateral surface of the temporal and parietal lobes, including the primary motor and sensory areas of the face, throat, hand, and arm and in the dominant hemisphere, the areas for speech. The middle cerebral artery is the artery most often occluded in stroke.

The middle cranial fossa

The middle cranial fossa is composed of the body and great wings of the sphenoid bone, the squamous and petrous parts of the temporal bones and the frontal angles of the parietal bones. This fossa is the "busiest" of the cranial fossae. This fossa contains laterally the temporal lobes of the brain. This fossa contains the optic chiasma, optic canal, sella turcica, and the hypophyseal fossa that houses the pituitary gland. Within this fossa, the superior orbital fissure, foramen rotundum, foramen ovale, foramen lacerum, and foramen spinosum are found. In the temporal bone, the hiatus for both the lesser and greater petrosal nerves are found. On the anterior surface of the petrous portion of the temporal bone is the trigeminal impression, which lodges the trigeminal ganglion (semilunar or gasserian) of the fifth nerve.

Oropharynx

The middle division of the pharynx; is continuous with the posterior oral cavity and is lined with stratified squamous epithelium. The oropharynx extends inferiorly from the soft palate to the hyoid bone. The opening into the oropharynx from the mouth is called the fauces. The lingual tonsils protrude into the oropharynx from the oral cavity at the base of the tongue. The anterolateral walls of the oropharynx support the palatine tonsils. It is a food and air passageway.

nasopalatine nerve

The nasopalatine nerve is a parasympathetic and sensory nerve that arises in the pterygopalatine ganglion, passes through the sphenopalatine foramen, across the roof of the nasal cavity to the nasal septum, and obliquely downward to and through the incisive canal, and innervates the glands and mucosa of the nasal septum and the anterior part of the hard palate. Important: The communication between the pterygopalatine fossa and the nasal cavity is the sphenopalatine foramen. The sphenopalatine artery and the nasopalatine nerve extend through the sphenopalatine foramen.

The ophthalmic artery is a branch of the

The ophthalmic artery is a branch of the internal carotid artery.

A new alien species is discovered that reproduces in a unique manner without gonads. This would mean that the species did not have: • The uterus in females and the epididymis in males • The vagina in females and the ductus deferens in males • The ovaries in females and the testes in males • The uterine tubes in females and the ejaculatory ducts in males

The ovaries in females and the testes in males The ovaries are elliptical organs, situated close to the side walls of the pelvis, and are supported by the broad ligament of the uterus. All of the ovary's blood and lymphatic vessels, and nerves enter at the hilum. Beneath its surface epithelium is a cortex that encloses the medulla at its core. The bulk of the ovary is the supporting structure called the stroma. Note: The main function of the ovaries is to produce mature ova. The ovaries also produce steroid hormones estrogen and progesterone. • Estrogen -- promote the development and maintenance of female sexual character¬istics and the proper sequence of events in the female reproductive cycle (menstrual cycle). • Progesterone -- maintains (along with estrogen) the lining of the uterus necessary for successful pregnancy. Remember: Ovulation takes place in the middle of each menstrual cycle -- a Graafian follicle ruptures to release its ovum, which enters the uterine tube. The empty follicle fills with blood and regresses into a corpus luteum. If the ovum is fertilized, the corpus luteum will persist and continue secreting progesterone to maintain pregnancy. If not, the corpus luteum shrinks into a small mass of collagenous tissue -- the corpus albicans. The testes (singular: testis) are paired structures that are suspended within the scrotum in the male. They produce spermatozoa and sex hormones (androgens). Sperm are produced in the seminiferous tubules and stored outside the testis in the epididymis until ejaculated. Androgens, the most important one being testosterone, are synthesized and secreted into the bloodstream by interstitial celk (of Leydig) found in the interstitium of the testis between the seminiferous tubules. Testosterone is responsible for growth and maintenance of male sexual characteristics and for sperm production.

Pharynx

The pharynx (the throat) is a tube that serves as a passageway for the respiratory and digestive tracts. It extends from the mouth and nasal cavities to the larynx and esophagus. The pharynx is divided into three regions: nasopharynx, oropharynx, and laryngopharynx

Exocrine glands include all of the following EXCEPT one. Which one is the EXCEPTION? • Sweat glands • The prostate gland • Bile-producing glands of the liver • The pituitary gland • Lacrimal glands • Gastric glands

The pituitary gland Exocrine glands are glands whose secretions pass into a system of ducts that lead ultimately to the exterior of the body. So the inner surface of the glands and the ducts that drain them are topologically continuous with the exterior of the body (the skin). Endocrine glands, in contrast, place their secretions into the internal environment -- the blood. Classification of exocrine glands: • Type of secretion 1. Mucous (secrete mucus = water + mucin) -- buccal glands, glands of the esophagus, cardiac and pyloric glands of the stomach 2. Serous (enzymes) -- parotid gland, pancreas and uterine glands 3. Mixed (mucous and serous) -- submandibular and sublingual salivary glands, glands of the nasal cavity, paranasal sinuses, nasopharynx, larynx, trachea, and bronchi • Mode of secretion 1. Merocrine -- only cell secretory product released from membrane bound secretory granules -- pancreatic acinar cells 2. Apocrine -- secretion of product plus small portion of cytoplasm -- fat droplet secretion by mammary glands 3. Holocrine -- entire cell with secretory product -- sebaceous glands of skin and nose • Structure of duct system 1. Unbranched -- "simple" glands -- sweat glands 2. Branched -- "compound" glands -- pancreas • Shape of secretory unit 1. Tubular -- cylindrical lumen surrounded by secretory cells -- sweat glands 2. Acinar (alveolar) -- dilated sac-like secretory unit -- sebaceous and mammary glands 3. Tubuloacinar (tubuloalveolar) -- intermediate in shape or having both tubular and alveolar secretory units -- major salivary glands

The posterior cranial fossa

The posterior cranial fossa, the deepest of the fossae, houses the cerebellum, medulla, and pons. Anteriorly, the posterior cranial fossa extends to the apex of the petrous temporal. Posteriorly, it is enclosed by the occipital bone. Laterally, portions of the squamous temporal and mastoid part of the temporal bone form its walls. It contains four important foramina, the internal acoustic meatus (in the petrous part of the temporal bone), the jugular foramen (between the sphenoid and occipital bones), the hypoglossal canal (in the occipital bone), and the foramen magnum (a large median opening in the floor of the fossa, where the medulla oblongata is continuous with the spinal cord).

CA delicate membrane covering the crown of a newly erupted tooth is called: ) • Perikymata • The primary enamel cuticle • Hertwig's root sheath • Plasmalemma

The primary enamel cuticle Also called Nasmyth's membrane. It is produced by the ameloblast cell after it produces the enamel rods. The primary enamel cuticle consists of two extremely thin layers (the inner one clear and structureless, the outer one cellular), covering the entire crown of newly erupted teeth and subsequently abraded by mastication; the cuticle is evident mi-croscopically as an amorphous material between the attachment epithelium and the tooth. This cuticle is worn away by mastication and cleaning. Nasmyth's membrane is replaced by an organic deposit called the pellicle, which is formed by salivary proteins. It is this pellicle that is invaded by bacteria to form bacterial plaque that, if not removed, will cause dental caries and periodontal disease. Remember: Enamel is incapable of repairing itself once it is destroyed (unlike dentin). After the ameloblasts are finished with both enamel apposition and maturation, they be-come part of the reduced enamel epithelium, along with the other portions of the com-pressed enamel organ. The reduced enamel epithelium fuses with the oral mucosa, creating a canal to allow the enamel cusp tip to erupt through the oral mucosa into the oral cavity. Unfortunately, the ameloblasts are lost forever as the fused tissues disintegrate during tooth eruption, preventing any further enamel apposition.

The pterygopalatine fossa

The pterygopalatine fossa is a small triangular space behind and below the orbital cavity. It communicates laterally with the infratemporal fossa through the pterygomaxillary fissure, medially with the nasal cavity through the sphenopalatine foramen, superiorly with the skull through the foramen rotundum, and anteriorly with the orbit through the inferior orbital fissure. The pterygopalatine ganglion lies in the pterygopalatine fossa just below the maxillary nerve (V-2). The pterygopalatine ganglion receives preganglionic parasympathetic fibers from the facial nerve by way of the greater petrosal nerve. The pterygopalatine ganglion sends postganglionic parasympathetic fibers to the lacrimal gland and glands in the palate and the nose. Note: The maxillary nerve (V-2) and the pterygopalatine portion of the maxillary artery pass through the pterygopalatine fossa.

Pulpal involvement of a carious lesion in a young child is much more likely because: • Caries progress faster in primary teeth • Caries can enter primary teeth from the enlarged apical foramen • The pulp chamber is larger in primary teeth compared to permanent teeth • Reparative dentin is not as functional in primary teeth as it is in permanent teeth

The pulp chamber is larger in primary teeth compared to permanent teeth The dental pulp is a connective tissue, and thus has all of the components of such a tissue: intercellular substance, tissue fluid, cells, lymphatics, vascular system, nerves, and fibers (mainly collagen and some reticular fibers). Cells found in the pulp: • Fibroblasts: most numerous • Odontoblasts: only cell bodies are located in the pulp • Undifferentiated mesenchymal cells • WBCs and RBCs Two types of nerves are associated with the pulp: • Myelinated nerves: are the axons of sensory or afferent neurons that are located in the dentinal tubules in dentin. The associated nerve cell bodies are located between the odon-toblasts' cell bodies in the odontoblastic layer of the pulp • Unmyelinated nerves: are associated with the blood vessels In addition to being the formative organ of the dentin, the pulp also has the following functions: • Nutritive -- the pulp keeps the organic components of the surrounding mineralized tissue supplied with moisture and nutrients • Sensory -- extremes in temperature, pressure, or trauma to the dentin or pulp are perceived as pain • Protective -- the formation of reparative or secondary dentin (by the odontoblasts) Important clinical information: Pulp capping is more successful in young teeth because: • The apical foramen of a young pulp is large • The young pulp contains more cells (odontoblastic) • The young pulp is very vascular • The young pulp has fewer fibrous elements • The young pulp has more tissue fluid *** The young pulp lacks a collateral circulation

bronchial arteries

The small bronchial arteries (which are branches of the descending aorta) also enter the hilum of each lung and deliver oxygen-rich blood to the tissues. The bronchial arteries tend to follow the bronchial tree to the respiratory bronchioles where the bronchial arteries anastomose with the pulmonary vessels.

The soft palate

The soft palate is continuous with the hard palate posteriorly and is "soft" because it does not have a bony substrate but contains a tough fibrous connective tissue sheet, the palatal aponeurosis, and is covered with a mucosa. Salivary glands are found in the underlying connective tissue. Posteriorly, the soft palate suspended in the oropharynx ends in the midline uvula. Remember: Most of the palatal muscles receive motor innervation from the pharyngeal plexus of nerves. The tensor muscles of the palate receive motor branches from the mandibular division of the trigeminal nerve (CN V-3). Sensory innervation is provided by the maxillary division of the trigeminal nerve (CN V-2). Arterial supply is from part-3 (pterygopalatine portion) of the maxillary artery.

The subclavian artery

The subclavian artery arises lateral to the common carotid artery. The subclavian artery gives off branches to supply both intracranial and extracranial structures, but its major destination is the upper extremity (arm). Remember: On the left side of the body, the left common carotid and left subclavian arteries arise from the arch of the aorta in the superior mediastinum.

The major gland(s) of the immune system is: • The thyroid gland • The adrenal glands • The pineal gland • The thymus gland

The thymus gland The thymus gland is a ductless gland located deep to the sternum and is situated in the superior mediastinum. At birth, the thymus weighs about a half of an ounce, and further enlarges to about an ounce by puberty. Following puberty, the thymus shrinks to a fatty fibrous remnant, weighing about a half of an ounce. While the thymus is part of the endocrine system, the thymus's primary function is that of a lymph organ. The thymus is the central control organ for the immune system. Lymphocytes originate from hemocytoblasts (stem cells) in red bone marrow. Those that enter the thymus mature and develop into activated T lymphocytes (i.e., able to respond to antigens encountered elsewhere in the body). They then divide into two groups: • Those that re-enter the blood; these are transported to developing secondary lymphoid tissues, such as lymph nodes and spleen. • Those that remain in the thymus gland and are the source of future generations of T lymphocytes. Many nutrients function as important cofactors in the manufacture, secretion, and function of thymic hormones. Zinc, vitamin B6, and vitamin C are perhaps the most critical. Zinc is perhaps the most critical mineral involved in thymus gland function and thymus hormone action. Zinc is involved in virtually every aspect of immunity. 1. The thymus has no afferent lymphatics or lymphatic nodules. 2. Other lymphoid organs originate exclusively from mesenchyme, whereas the thymus has a double embryologic origin. The lymphocytes are derived from hematopoietic stem cells (mesenchyme), while Hassall's corpuscles (epithelium) are derived from endoderm of the third pharyngeal pouch. 3. The arteries supplying the thymus are derived from the internal mammary, superior thyroid, and inferior thyroid arteries. It is innervated by the vagus nerve.

blood supply of tongue

The tongue is supplied by the lingual artery, the tonsillar branch of the facial artery, and the ascending pharyngeal artery. The veins drain into the internal jugular vein. The lingual artery arises from the external carotid artery at the level of the tip of the greater horn of the hyoid bone in the carotid triangle. Branches include: dorsal lingual: supplies the base and body of the tongue (posterior superficial tongue) suprahyoid: supplies the suprahyoid muscles sublingual: supplies the mylohyoid muscle, sublingual salivary gland, and mucous membranes of the floor of the mouth deep lingual (terminal branch): supplies the apex of the tongue Remember (information about the tongue):

tonsillar artery, ascending pharyngeal artery, common trunk

The tonsillar artery is a branch of the facial artery that also supplies blood to the palatine tonsil. The ascending pharyngeal artery is the smallest branch of the external carotid artery. Branches include the pharyngeal and meningeal arteries. The lingual artery and facial artery often arise from a common trunk of the external carotid artery.

Trachea

The trachea is a membranous tube that begins below the cricoid cartilage (at the level of the 6th cervical vertebra) of the larynx and ends at the level of the sternal angle (the 5th thoracic vertebra). A series of C-shaped rings of hyaline cartilage strengthen the trachea and prevent it from collapsing during inspiration. The trachea is lined with ciliated pseudostratified columnar epithelium and mucous-secreting goblet cells, which trap inhaled debris. Ciliary action moves debris toward the pharynx for removal by coughing.

Nose part 2

The vestibules are lined with nonkeratinized stratified squamous epithelium. The conchae of the nasal fossae are lined with pseudostratified ciliated columnar epithelium. The olfactory epithelium is very prominent in the upper medial portion of the nasal cavity. The nasal cavity receives sensory innervation from the olfactory nerve for smell and from the trigeminal nerve for other sensations. The nasal cavity's blood supply is from branches of the ophthalmic and maxillary arteries. The tickling sensation felt in the nasal cavity just prior to a sneeze is carried in the maxillary division of the trigeminal nerve. During a sinus attack, painful sensation from the ethmoid cells is carried in the nasociliary nerve. All of the paranasal sinuses drain into the middle meatus, except the sphenoid sinus, which drains almost directly down the throat.

( Which comparison between the large intestine and small intestine is false? ) • The lumen of the large intestine is of a greater diameter than that of the small intestine • The smooth muscle coat of the large intestine consists of three bands called taeniae coli that cause the colon to form pouches (called haustra). The small intestine lacks this characteristic • The walls of the large intestine have more villi than the small intestine • The external surface of the large intestine has small areas of fat-filled peritoneum called epiploic appendages. The small intestine lacks this characteristic • The large intestine is about one-fourth the size of the small intestine

The walls of the large intestine have more villi than the small intestine *** This is false; the walls of the large intestine lack villi. The large intestine consists of the colon and rectum. The colon is composed of various parts: the cecum, ascending colon, transverse colon, descending colon, and sigmoid colon. The appendix is attached to the cecum. The rectum is the second to last part of the digestive tract and leads into the last part, the anus. • The large intestine lacks folds or villi. It is characterized by many tubular intestinal glands with large num¬bers of goblet cells. This is sometimes described as a glandular epithelium • The large intestine is the site of water absorption (via columnar absorptive cells) and is also the site of for¬mation of the feces. The secretions of the goblet cells provide lubrication for the luminal surfaces • Abundant lymphatic tissue is common in the lamina propria (owing to the large bacterial population in the lumen of the large intestine) • Whereas the circular smooth muscle layer is continuous, the longitudinal smooth muscle of the muscularis is in the form of three thick bands, known as taeniae coli • The anal region, unlike the rest of the large intestine, has a series of longitudinal folds, and the epithelium becomes a stratified squamous epithelium The Large Intestine Is Composed of Three Parts: 1. Cecum: the beginning of the large intestine, bag-like structure that receives the ileum of the small intestine. The vermiform appendix is a narrow, blind tube that extends downward from the cecum. It contains a large amount of lymphoid tissue. 2. Colon: parts of the colon include the ascending colon -- the shortest part of the large intestine that extends upward from the cecum on the right posterior abdominal wall. The transverse colon ex¬tends across the upper abdomen where the colon bends downward along the left posterior abdominal wall as the descending colon. Low in the abdomen, the colon curves into the pelvis toward the midline as the S-shaped sigmoid colon. 3. Rectum: extends from the sigmoid colon to the anus. It is straight and does not possess the taeniae coli that are present in the rest of the large intestine. The rectum ends as the anal canal (3 - 4 cm), which opens to the exterior through the anus. The anal canal is surrounded by the internal and external sphincter muscles that control the expulsion of contents (bowel movements). Important: Unlike those of the rest of the GI tract, longitudinal muscles do not form a continuous layer around the large intestine. Instead three bands of longitudinal muscle, called taeniae coli, run the length of the colon. Contractions gather the colon into bands (haustra), giving the colon its "puckered" appearance.

All of the following characteristics are true concerning veins EXCEPT one. • Thick tunica media with a lot of muscle fibers • Thick tunica adventitia with little elastic tissue • Larger lumen and thinner walls than the arteries they accompany • Some contain valves and vasa vasorum

Thick tunica media with a lot of muscle fibers *** Veins have a thin tunica media with few muscle fibers.

The splanchnic nerves (greater, lesser, and least) arise from the: • Cervical sympathetic ganglion (chain) • Thoracic sympathetic ganglion (chain) • Lumbar sympathetic ganglion (chain) • Sacral sympathetic ganglion (chain)

Thoracic sympathetic ganglion (chain) Remember: Paravertebral sympathetic ganglia lie on each side of the vertebrae and are connected to form the sympathetic chain or trunk. These nerves arise from thoracic ganglia (T5 - T12). Note: They all pass through the diaphragm. The preganglionic sympathetic fibers may pass through the ganglia on the thoracic part of the sympathetic trunk without synapsing. These myelinated fibers form the splanchnic nerves, of which there are three: 1. Greater -- formed from sympathetic fibers from T5 - T9. The nerve passes through the crura of the diaphragm to end in the celiac ganglion. 2. Lesser -- formed from sympathetic fibers from T10 - T11. The nerve pass through the diaphragm with the greater to end in the aorticorenal ganglion. 3. Least -- arises from the last thoracic ganglion, and, piercing the diaphragm, ends in the renal plexus. Important: Thoracic splanchnic nerves (specifically the greater splanchnic nerve) to the celiac plexus consist primarily of preganglionic visceral efferent fibers. The postganglionic fibers arise from the excitor cells in the celiac plexus and are distributed to the smooth muscle and glands of the viscera.

A patient with DiGeorge syndrome can present with cleft palate, autism, heart defects, and a hypoplastic: j • Thyroid gland • Thymus gland • Pituitary gland • Pancreas

Thymus gland *** Defects in chromosome 22 (cause of most cases of DiGeorge syndrome) may cause a baby's thymus gland to be smaller than normal (hypoplastic). In some cases, children with DiGeorge syndrome don't have a thymus gland at all. Remember: The primary function of the thymus is the processing and maturation of spe¬cial lymphocytes (white blood cells) called T lymphocytes or T cells, which are associated with antibody production. T lymphocytes migrate from the bone marrow to the thymus, where they mature and differentiate until activated. While in the thymus, the lymphocytes do not respond to pathogens and foreign agents. After the lymphocytes have matured, they enter the blood and go to other lymphatic organs, where the lymphocytes help pro¬vide defense against disease. The thymus also produces a hormone, thymosin, which stimulates the maturation of lymphocytes in other lymphatic organs. Note: The thymus gland also produces thymic lymphopoietic factor (TLF), which confers immunological competence on thymus-dependent cells and induces lympho-poiesis. The thymus gland is a primary lymphoid organ (along with the spleen, tonsils, lymph nodes, and Peyer's patches) that consists of two lobes surrounded by a thin layer of connective tissue. The thymus gland is located deep to the sternum in the superior mediastinum. This gland consists of an outer cortex that is primarily lymphocytes. The inner medulla also contains lymphocytes and Hassall's corpuscles. These corpuscles are thought to be vestiges of epithelium; their function is unknown. Important: This organ appears to be the master organ in immunogenesis in the young and is believed by some (but not all) to monitor the total lymphoid system throughout life.

Follicular "colloid" is a protein substance that stores: • Thyroglobulin • Triiodothyronine • Thyrotropin • Thyroxine

Thyrogjobulin Thyroid epithelial cells (follicular cells) -- the cells responsible for synthesis of thyroid hormone -- are arranged in spheres called thyroid follicles. These follicles are filled with colloid. Colloid is composed of thyroglobulin and iodine and is the storage form of the thyroid hormones T3 (iodothyronine) and T4 (thyroxine or tetraiodothyronine). When the pituitary gland secretes thyrotropin, the colloid becomes active, and thyroglobulin molecules are released and taken back into the follicular cells by endocytosis, where the molecules are broken down into thyroid hormones, thyroxine (T4) and triiodothyronine (T3). Note: The T3 and T4 are collectively referred to as the thyroid hormones. This hormone then passes out of the follicular cells and enters the bloodstream. Within the bloodstream, almost all of the thyroid hormones are bound to plasma proteins such as thyroid-binding globulin (TBG). The thyroid normally produces about 10% T3 and 90% T4. In the tissues, however, much of the T4 is converted to T3, which is the major active form of the thyroid hormones at the cellular level. Follicular cells remain inactive at times of low thyroid hormone need and can be activated when it is necessary for the mobilization of colloid found within the thyroid follicle. Note: Metabolically inactive follicular colloid will stain acidophilic (stains strongly with acid stains) while metabolically active follicular colloid will stain basophilic (stains strongly with basic stains).

Dentin is considered a living tissue because of odontoblastic cell processes known as: • Triacetate fiber • Tomes' fiber • Tag fiber • Korff's fiber

Tomes' fiber These odontoblastic processes (Tomes' fibers) occupy the dentinal tubules. There is one per odontoblast. It is because of these odontoblastic cell processes that dentin is considered a living tissue, with the capability to react to different stimuli and produce secondary, sclerotic, and/or reparative dentin. Dentin sensitivity is not well understood. One theory is that Tomes' fibers are receptors and transmit an impulse to pulpal nerves. The preferred theory is that fluid movement within the tubules, in response to a stimulus, triggers the pulpal nerves. Remember: The odontoblasts begin dentin formation (dentinogenesis) immediately before enamel formation by the ameloblasts. Dentinogenesis begins with the odontoblasts laying down a dentin matrix or predentin, moving from the DEJ inward toward the pulp. The most recently formed layer of dentin is always adjacent to the pulpal surface. Note: Predentin or dentin matrix is a mesenchymal product consisting of nonmineralized collagen fibers. Remember: Amelogenesis is the process of enamel matrix formation that occurs during the appositional stage of tooth development. Enamel matrix is produced by ameloblast cells. These cells are columnar cells that differentiate during the apposition stage in the crown area. The enamel matrix is secreted from each ameloblast from its Tomes' process. The Tomes' process is the secretory surface of the ameloblast that faces the dentinoenamel junction (DEJ). 1. The cell body of the odontoblast lies in the pulp cavity. Notes 2. The dentinal tubules are S-shaped (curvature) in the crown due to overcrowding of odontoblasts. This curvature of the tubules decreases in root dentin.

Histologically, the dentin of the root is distinguished from the dentin of the crown by the presence of: • Incremental lines of Retzius • Rete pegs • Tomes' granular layer • Sharpey's fibers

Tomes' granular layer (also called the granular layer of Tomes) Important: Histologically, the dentin of the root is distinguished readily from the dentin of the crown by the presence of Tomes' granular layer. Tomes' granular layer is most often found in the peripheral portion of the dentin beneath the root's cementum, adjacent to the dentinocemental junction (DCJ). This area only looks granular because of its spotty microscopic appearance. The cause of the change in this region of dentin is unknown. It may be due to less calcified areas of dentin similar to interglobular dentin or loops of the terminal portions of branching dentinal tubules found near the DCJ similar to that of the DEJ. Interglobular dentin differs from Tomes' granular layer in that interglobular dentin usually occurs a short distance inside the DEJ. Remember: Enamel formation begins at the future cusp and spreads down the cusp slope. As the ameloblasts retreat in incremental steps, the ameloblasts create an artifact in the enamel called the lines of Retzius. Where these lines terminate at the tooth surface, they create tiny valleys on the tooth surface that travel circumferentially around the crown known as perikymata or imbrication lines of Pickerill. One of the lines of Retzius is accentuated and is more obvious than the others. It is the neonatal line that marks the division between enamel fonned before birth and that which is produced after birth -- this neonatal line is found in all deciduous teeth and in the larger cusps of the permanent first molars. 1. Globular dentin: refers to areas of both primary and secondary mineraliza-Notest tion in dentin. 2. Interglobular dentin: refers to areas in dentin where only primary mineral-ization has occurred within the predentin. Interglobular dentin is slightly less mineralized than globular dentin. Interglobular dentin is especially evident in coronal dentin and near the DEJ.

Which type of epithelium, characterized by multiple layers that can contract and expand, would be found lining the urinary bladder? • Simple squamous epithelium • Stratified columnar epithelium • Stratified cuboidal • Transitional epithelium

Transitional epithelium Simple squamous epithelium -- single layer of thin, flat cells; functions in gas exchange; lines blood vessels and various membranes: • Endothelium lining the cardiovascular system • Epithelium lining the alveoli in lungs • Mesothelium lining body cavities and coats organs of these cavities Simple cuboidal epithelium-- single layer of cube-shaped cells; carries on secretion and absorption: • Epithelium lining collecting ducts, proximal, and distal tubules of the kidney • Epithelium lining thyroid follicles Simple columnar epithelium -- elongated cells; functions in protection, secretion and absorption: • Lining of the small and large intestine, the gallbladder, and the stomach • Uterine epithelium • Salivary gland striated ducts • Internal lining of the majority of the tubular gastrointestinal tract Stratified squamous epithelium -- composed of many layers of cells; protects underlying cells from environmental fluctuations: • Epidermis of the skin (keratinized) • Lining of the esophagus (usually not keratinized) Stratified cuboidal epithelium -- composed of many layers of cube-shaped cells: • Ducts of the sweat glands Stratified columnar epithelium -- composed of many layers of elongated cells: • Large ducts of salivary glands • Male urethra Specialized epithelium: - Pseudostratified columnar epithelium: elongated cells atop one another with nuclei located at two or more levels within cells; may have cilia that function to move fluids past the cells: • Lining of the upper respiratory tract • Ureter - Transitional epithelium -- specialized to undergo distension; helps prevent urinary fluids from diffusing outwards: • Bladder • Lining of parts of the male reproductive system

Most of the muscles that act on the shoulder girdle and upper limb joints are supplied by branches of the brachial plexus. Which of the following is not? • Levator scapulae • Rhomboid major • Rhomboid minor • Trapezius • Serratus anterior • Pectoralis minor • Subclavius

Trapezius -- is innervated by the accessory nerve (CN XI)

In an automobile accident, an anatomy professor fractures his humerus. He notices that he is unable to extend his forearm, but still is able to flex the forearm. Which muscle of the upper arm primarily extends the forearm? I • Biceps brachii • Coracobrachialis • Brachialis • Triceps brachii

Triceps brachii At the shoulder, important muscles involved in the movement include the deltoid, which makes the rounded contour over the upper surface of the arm and shoulder. At the elbow joint, important muscles for flexion include biceps brachii and brachialis, while the main extensor muscle is the triceps. Note: The radial nerve is most commonly injured in a mid-humeral shaft fracture, because this nerve runs in the radial (spiral) groove of the humerus. The biceps brachii participates in flexion at both the glenohumeral and humeroulnar joints.

Which cranial nerve supplies the muscles derived from the first pair of branchial arches? • Oculomotor • Facial • Trigeminal • Glossopharyngeal • Vagus

Trigeminal

cA 62-year-old woman complains of an "excruciating, stabbing pain" on the right side of her face on her cheek, lip, and nose. She complains that this is the worst pain she has felt in her life. The pain is triggered by light contact, chewing, or even drafts of cold air. The working diagnosis is a neuralgia of what cranial nerve (the principal sensory nerve to the head and face)? • Facial nerve (CN VII) • Abducens nerve (CN VI) • Glossopharyngeal nerve (CN IX) • Trigeminal nerve (CN V)

Trigeminal nerve (CN The trigeminal nerve exits the inferolateral pons as a sensory and motor root. The larger sensory root enters the trigeminal (semilunar, gasserian) ganglion in the middle cranial fossa. The three sensory divisions of the nerve arise from the ganglion and leave the cranial cavity through foramina in the sphenoid bone. The smaller motor root passes under the ganglion and joins the mandibular division as it exits through the foramen ovale. The mandibular division innervates eight muscles. Somatic sensory cell bodies of the ganglion's sensory fibers enter the: • Ophthalmic division (V-1) to supply general sensation to the orbit and skin of face above eyes • Maxillary division (V-2) to supply general sensation to the nasal cavity, maxillary teeth, palate, and skin over maxilla • Mandibular division (V-3) to supply general sensation to the mandible, TMJ, mandibular teeth, floor of mouth, tongue, and skin of mandible The axons of the neurons enter the pons through the sensory root and terminate in one of the three nuclei of the trigeminal sensory nuclear complex. • Mesencephalic nucleus mediates proprioception (ex: muscle spindle) • Chief or pontine nucleus mediates discriminative sensation (ex: light touch) • Spinal nucleus (mediates pain and temperature from the head and neck) can be divided into three regions along its length; the region closest to the mouth is called subnucleus oralis, the middle region is called subnucleus interpolaris, and the region closest to the tail is called subnucleus caudalis. The pain fibers actually synapse in subnucleus caudalis. Note: Proprioceptive fibers from muscles and the TMJ are found only in the mandibular division. The cell bodies of proprioceptive first order neurons are found in the mesencephalic nucleus, not the trigeminal ganglion. Branchiomeric (meaning derived from embryonic branchial arches) motor fibers innervate the temporalis, masseter, medial and lateral pterygoid, anterior belly of the digastric, mylohyoid, tensor tympani, and tensor veli palatini (palati).

The semilunar ganglion is a large, flattened, sensory ganglion of the , lying close to the cavernous sinus in the middle cranial fossa. • Hypoglossal nerve (CN XII) • Facial nerve (CN VII) • Oculomotor nerve (CN III) • Trigeminal nerve (CN V)

Trigeminal nerve (CN 1) The trigeminal nerve, or CN V, is the most voluminous of all of the cranial nerves. Part of the first branchial arch or mandibular arch, the trigeminal nerve is sensorial for the fa¬cial regions and motor for the masticatory muscles. The trigeminal nerve exits the inferolateral pons as a sensory and motor root. The larger sensory root enters the trigeminal (semilunar or Gasser) ganglion in the middle cranial fossa. The three sensory divisions of the nerve arise from the ganglion and leave the cranial cavity through foramina in the sphenoid bone. The smaller motor root passes under the ganglion and joins the mandibular division as it exits through the foramen ovale. The mandibular division innervates eight muscles. Remember: The geniculate ganglion is an L-shaped collection of fibers and sensory neurons of the facial nerve located in the facial canal of the head. The ganglion receives fibers from the motor, sensory, and parasympathetic components of the facial nerve and sends fibers that will innervate the lacrimal glands, submandibular glands, sublingual glands, tongue (anterior two-thirds), palate, pharynx, external auditory meatus, stapedius, posterior belly of the digastric muscle, stylohyoid muscle, and muscles of facial expression. The greater petrosal nerve (branch of the facial nerve) arises from the geniculate ganglion. This nerve is the parasympathetic root of the pterygopalatine ganglion. It runs through the facial canal and groove on the petrous portion of the temporal bone beside the foramen lacerum through the pterygoid canal to reach the pterygopalatine ganglion. Important: This nerve carries preganglionic parasympathetic fibers to the pterygopalatine ganglion (for the lacrimal glands as well as glands of the palate and nasal cavity). 1. Taste fibers to the posterior one-third of the tongue are from the glosso¬Notes pharyngeal nerve. 2. Loss of lacrimation (dry eye) can be due to an injury to the greater petrosal nerve.

Name the molecule that lies along the surface of F-actin and physically covers actin binding sites during the resting state. • G-actin • Tropomyosin • Troponin • Light meromyosin • Heavy meromyosin

Tropomyosin The main contractile system of all muscular tissue is based on the interactions of two proteins, actin and myosin. The system of these proteins is sometimes called the actin-myosin contractile system. Actin filaments (thin myofilaments, 5-8 nm in diameter) are composed of: • Actin: globular actin (G-actin) molecules are arranged into double helical chains called fibrous actin (F-actin) • Tropomyosin: long, thread-like molecules, lie along the surface of F-actin strands and physically cover actin binding sites during the resting state • Troponin: a small, oval-shaped molecule attached to each tropomyosin Myosin filaments (thick myofilaments, 12-18 nm in diameter) are composed of: • Myosin, which has two components: 1. Light meromyosin (LMM) makes up the rod-like backbone of myosin fila-ments. 2. Heavy meromyosin (HMM) forms the shorter globular lateral cross-bridges, which link to the binding sites on the actin molecules during contraction. Skeletal muscle contracts when a stimulus from the nervous system excites the individual muscle fibers. This starts a series of events that lead to interactions between the myosin (thick filaments) and actin (thin filaments) of the sarcomeres of the fibers.

During the fourth week of prenatal development, within the embryonic perio tongue development begins as a triangular median swelling, called the: • Foramen cecum • Sulcus terminalis • Tuberculum impar • Epiglottic swelling

Tuberculum impar or median tongue bud The tuberculum impar is a triangular median swelling that is located in the midline, on the floor of the primitive pharynx, in the embryo's conjoined nasal and oral cavities. This structure gives the first indication of tongue development at about the fourth week of embryonic life. Soon, two distal tongue buds (lateral lingual swellings) develop on each side of the median tongue bud. All of these anterior swellings are from the growth of mesenchyme of the first branchial arches (or mandibular arches) and fuse to form the anterior two-thirds or body of the tongue. The posterior one-third or base of the tongue is formed by a pair of swellings, the copula ((from the third and parts of the fourth branchial arches). Even farther posterior to the copula is the projection of a third median swelling, the epiglottic swelling, which develops from the mesenchyme of the posterior parts of the fourth branchial arches. This swelling marks the development of the most posterior region of the tongue and of the future epiglottis. Remember: The branchial (pharyngeal) arches are stacked bilateral swellings of tissue that appear inferior to the stomodeum during the fourth week of embryonic development. These branchial arches are six pairs of U-shaped bars with a core mesenchyme formed by neural crest cells that migrate to the neck region. The branchial arches are covered externally by ectoderm and lined internally by endoderm. These arches support the lateral walls of the primitive pharynx. 1. Bifid tongue is the result of lack of fusion of the distal tongue buds (or lateral swellings). This seems to be common in South American infants. 2. The fifth branchial arches are so rudimentary that they are absent in humans or are included with the fourth branchial arches. Between the sixth and eighth weeks of prenatal development, the three major salivary glands begin as epithelial proliferations, or buds, from the ectodermal lining of the primitive mouth (stomodeum). The rounded terminal ends of these epithelial buds grow into the underlying mesenchyme, producing the secretory cells, or glandular acini, and the ductal system. The parotid glands appear early in the sixth week and are the first to form. The submandibular glands appear late in the sixth week, and the sublingual glands appear in the eighth week.

The walls of blood vessels are composed of the following tunics (layers):

Tunica intima - innermost layer, consists of a layer of simple squamous epithelium (called endothelium) and a thin connective-tissue basement membrane. The endothelium of this layer is the only layer present in vessels of all sizes. Note: Atherosclerosis is the emergence of plaque between the basement membrane and the endothelial cells of the tunica intima. Tunica media - middle layer, is usually very thick in arteries, and consists of smooth muscle fibers mixed with elastic fibers. Increases or decreases lumen diameter; affects blood pressure. Tunica adventitia - an outer layer of connective tissue, containing elastic and collagenous fibers. The tunica adventitia of the larger vessels is infiltrated with a system of tiny blood vessels called vasa vasorum ("vessels of the vessels') that nourish the more external tissues of the blood vessel wall.

Branches of the internal thoracic artery include:

Two anterior intercostal arteries for the upper six intercostal spaces. Perforating arteries, which accompany the termianl branches of the corresponding intercostal nerves. The pericardiacophrenic artery, which accompanies the phrenic nerve and supplies the pericardium. Mediastinal arteries to the contents of the anterior mediastinum, for example, the thymus gland. The superior epigastric artery, which enters the rectus sheath and supplies the rectus muscle as far as the umbilicus. The musculophrenic artery, which runs around the costal margin of the diaphragm and supplies the lower intercostal spaces and the diaphragm. Note: The inferior epigastric artery, a branch of the external iliac artery, anastomoses with the superior epigastric artery in the rectus sheath in the area of the umbilicus.

Which type of collagen is unique to basement membranes? • Type I • Type II • Type III • Type IV

Type IV *** 90% of the collagen in the body is in types I, II, III, and IV. Type I is associated with (bONE). Type II is associated with cartilage (carTWOilage). Type III is associated with reticular fibers (reTHREEicular). Type IV is associated with the floor (FOUR) or the basement membrane. The basement membrane is a thin, acellular structure always located between any form of epithelium and its underlying connective tissue. The basement membrane consists of two layers: • The basal lamina (produced by the epithelial cells): superficial portion of the base¬ment membrane. Consists of two layers microscopically: - The lamina lucida: clear layer, closer to the epithelium - The lamina densa: dense layer, closer to the connective tissue • The reticular lamina: this layer is a thin layer composed of type IV collagen (which is unique to basement membranes) fibers as well as reticular fibers produced and se¬creted by the underlying connective tissue. Attachment mechanisms are also part of the basement membrane. These involve hemidesmosomes with their attachment plaque, tonofilaments from the epithelium, and the anchoring collagen fibers from the connective tissue.

Oxygenated blood leaves the placenta and enters the fetus through the: • Foramen ovale • Ductus venosus • Umbilical arteries • Ductus arteriosum • Umbilical vein

Umbilical vein Blood leaves the placenta and enters the fetus through the umbilical vein. It is the only fetal vessel to carry blood that is rich in oxygen and nutrients. All of the other vessels carry a mixture of arterial and venous blood. After circulating in the fetus, the blood returns to the placenta through the umbilical arteries.

Oxytocin and vasopressin are synthesized in the hypoyhalamus and are transported to the pituitary gland for storage by way of: • Myelinated nerve fibers • Both myelinated and unmyelinated nerve fibers • Unmyelinated nerve fibers

Unmyelinated nerve fibers As opposed to the anterior lobe (adenohypophysis), which presents epithelial characteristics, the posterior lobe (neurohypophysis) consists of about 100,000 unmyelinated axons of secretory nerve cells, the cell bodies of which are housed in the supraoptic and paraventricular nuclei of the hypothalamus. The secretory products (oxytocin and vasopressin [ADM) are transported down the axons and stored in the axon terminals of these neurons in the neurohypophysis. These products are released into the bloodstream when needed. Thus, oxytocin and vasopressin are synthesized in the hypothalamus and stored in and released by the neurohypophysis (specifically, the pars nervosa). Important: The hypothalamo-hypophyseal portal tract refers to the way in which secretions by the anterior pituitary are controlled by hormones called hypothalamic releasing and inhibiting factors. These factors are secreted within the hypothalamus itself and then conducted to the anterior pituitary through the rich vascular hypophyseal portal system. This system of blood vessels links the hypothalamus and the anterior pituitary. This system allows endocrine communication between the two structures. Remember: The pituitary gland is an endocrine gland located in the sella turcica of the sphenoid bone, attached to the hypothalamus by a stalk (infundibulum). Through the infundibulum pass important nerve tracts and substances that act upon the pituitary.

why is urea produced

Urea is produced when foods containing protein, such as meat, are broken down in the body. The Urinary system removes nitrogenous waste as urea from the blood.

The most common type of urinary tract infection (UTI) is an infection of the urinary bladder called cystitis. Women more commonly get UTIs because what passageway between the urinary bladder and outside of the body is shorter in females than in males? • Ureter • Urethra • Ductus deferens • Theca interna

Urethra The urethra is a tube that conveys urine from the urinary bladder to the outside of the body. The wall of the urethra is lined with mucous membranes and contains a relatively thick layer of smooth mus¬cle tissue. It also contains numerous mucous glands, called "urethral glands," that secrete mucus into the urethral canal. The urethra being shorter in the female (about 4 cm long) than it is in the male (about 20 cm long) subjects the female to more frequent bladder infections. Because the male urethra travels in the penis, the male urethra is longer than the female urethra. This requires an invading organism to travel a greater distance to gain access to the urinary bladder. Eliminating urine by the male tends to flush the urethra before an invading organism can reach the urinary bladder. 1. The female urethra opens into the vestibule between the clitoris and the vagina. 2. In the male, the urethra also conveys semen from the reproductive organs during ejacula- tion. The male urethra is divided into three parts: - prostatic: it is the widest and most dilatable portion of the urethra - membranous: it is the shortest and least dilatable portion of the urethra - penile: it is the longest and narrowest portion; bulbourethral glands open into it 3. The ureter is a paired passageway that transports the urine from the kidney to the urinary bladder for concentration and storage until the urine is voided. Important: The accessory glands, which produce most of the semen, include the: • The seminal vesicles are paired sacs at the base of the bladder. • The bulbourethral glands (Cowper's glands), also paired, are located inferior to the prostate gland. • The prostate gland is shaped like an inverted pyramid and lies under the bladder, with the apex pointing downward. Emerging from the neck of the bladder, the urethra runs vertically through the prostate gland, and exits just in front of the apex. The prostate gland has two major groups of glands: - periurethral glands: are in the central zone surrounding the urethra - main glands: are in the peripheral zone *** All the glands open into the prostatic urethra and secrete the enzyme acid phosphatase, fib¬rinolysin, and some proteins. Prostatic secretion makes up about 25% of semen.

Tubal ligation is the permanent sterilization of women in which this structure, where fertilization occurs, is severed and sealed. • Ovaries • Uterine tubes • Uterus • Labia majora

Uterine tubes -- also called fallopian tubes

The most minor manifestation of a cleft palate would result in a bind: ) • Soft palate • Hard palate • Uvula • Glossopalatine arch • Pharyngopalatine arch

Uvula The palate is the roof of the oral cavity, consisting anteriorly of the bony hard palate and posteri¬orly of the soft palate. Transverse ridges, called palatal rugae, are located along the mucous membranes of the hard palate, where they serve as friction bands against which the tongue is placed during swallowing. The uvula is suspended from the soft palate. During swallowing, the soft palate and uvula are drawn upward, closing the nasopharynx and preventing food and fluid from entering the nasal cavity. The neurovascular bundle of the soft palate is the lesser palatine vein, artery, and nerve. The pharyngeal plexus of nerves supplies the uvular area. 1. The aperture by which the mouth communicates with the pharynx is called the isth¬mus faucium. It is bounded, above, by the soft palate; below, by the dorsum of the tongue; and on either side, by the glossopalatine arch. 2. The glossopalatine (palatoglossus) arch (anterior pillar of fauces or anterior faucial pillar) on either side runs downward, lateralward, and forward to the side of the base of the tongue, and is formed by the projection of the palatoglossus muscle with its cover¬ing mucous membrane. 3. The pharyngopalatine (palatopharyngeal) arch (posterior pillar of fauces or poste¬rior faucial pillar) is larger and projects farther toward the middle line than the anteri¬or; the pharyngopalatine arch runs downward, lateral, and backward to the side of the pharynx, and is formed by the projection of the palatopharyngeus muscle, covered by mucous membrane. On either side, the two arches are separated below by a triangular interval, in which the palatine tonsil is lodged. 3. The palatal salivary glands are found beneath the mucous membrane of the hard and soft palate. They are mostly of the mucous type and contribute to the oral fluid. 4. Bifid uvula results from failure of complete fusion of the palatine shelves. A unilat¬erally damaged pharyngeal plexus of nerves causes the uvula to deviate to the opposite side. This is because the uvular muscle shortens the uvula when it contracts and the mus¬cle on the intact side pulls the uvula toward that side.

Which cranial nerve (which technically does not arise from the brain) is the only nerve to start in the cranium and extend below to the head, and innervates the viscera? • Trigeminal (CN V) • Facial (CN VII) • Vagus (CN .X) • Hypoglossal (CN XII)

Vagu s (CA/ X) The vagus nerve is a mixed nerve that leaves the brain from the medulla and passes out of the cranial cavity through the jugular foramen. The vagus nerve descends in the neck in the carotid sheath behind the internal and common carotid arteries and the internal jugular vein. Both right and left vagal trunks pass through the posterior mediastinum on the esophagus and enter the abdominal cavity with the esophagus. The vagus nerves supply the viscera of the neck, thorax, and abdomen to the left colic (splenic) flexure of the large intestine. 1. The abdominal viscera below the left colic flexure and the pelvic and genitalia are Notes supplied with parasympathetic preganglionics from the pelvic splanchnic nerves. 2. The pharyngeal plexus of nerves contains both motor and sensory components. The motor nerves are believed to come from the vagus nerve.

Which of the following travels with the esophagus through the esophageal opening in the diaphragm? • Aorta • Thoracic duct • Azygos vein • Vagus nerve • Right phrenic nerve

Vagus nerve *** You can remember this because the vAGUS travels with the esophAGUS. The diaphragm is a flat muscle in a dome-like shape that separates the chest cavity from the abdominal cavity. The diaphragm is pierced by several structures that pass between the two cavities. The three largest of these structures are the esophagus, the aorta, and the inferior vena cava. The central part of the diaphragm is the central tendon, which is fibrous rather than muscular. The undersurface of the diaphragm forms the roof of the abdominal cavity, and lies over the stomach on the left and the liver on the right. When the diaphragm contracts, it pulls down into the abdomen, thus creating a vacuum in the chest cavity that draws air into the lungs. Exhaling is done by contracting the mus¬cles of the abdomen to force the diaphragm upward when it is relaxed. During inspira¬tion the diaphragm moves down, increasing the volume in the thoracic cavity. During expiration the diaphragm moves up, decreasing the volume in the thoracic cavity. The upper surface is in contact with the heart and lungs; the lower surface contacts the liver, stomach, and spleen. Important: The esophagus passes through the diaphragm, while the aorta, azygos vein, and thoracic duct pass posterior to it. The diaphragm has three openings: 1. Aortic opening: transmits the aorta, the thoracic duct, and the azygos vein. 2. Esophageal opening: transmits the esophagus and right and left vagus nerves. 3. Caval opening: transmits the inferior vena cava and the right phrenic nerve. Other respiratory muscles include the external, internal and innermost intercostals, sub-costal, and transversus thoracis. These muscles are all innervated by the intercostal nerve while the diaphragm is innervated by the phrenic nerve. Note: The phrenic nerve travels through the thorax between the pericardium and the pleura.

Simple squamous epithelium is most likely found lining the: • Upper respiratory tract • Urinary bladder • Vasculature • Esophagus

Vasculature Epithelial tissues can be classified into two main categories on the basis of their arrangement into layers or cells: 1. Simple: consists of a single layer of epithelial cells. The further classification of tissue in¬volves different types of epithelial cells according to shape; they can be: • Simple squamous epithelium: consists of flattened, platelike epithelial cells. Lines blood and lymphatic vessels, heart, and serous cavities and lines the air sacs (alveoli) of the lungs • Simple cuboidal epithelium: consists of cube-shaped cells that line the ducts of various glands, such as certain portions of the salivary gland ducts. • Simple columnar epithelium: consists of rectangular or tall cells, such as in the lining of other salivary ducts, as well as the inner enamel epithelium, whose cells become ameloblasts 2. Stratified: consists of two or more layers of cells, with only the lower level contacting the basement membrane. Only the shape of the surface layer is used to determine the classification of stratified epithelium: • Stratified squamous epithelium: most of the epithelial tissues in the body are of this type, which include the superficial portion of the skin and oral mucosa. Can be keratinized or nonkeratinized *** Stratified epithelium can also be cuboidal or columnar or a combination of types. Epithelial tissue can also be classified as pseudostratified epithelium. This epithelium falsely ap¬pears as multiple layers because the cells' nuclei appear at different levels. This type of epithelium lines the upper respiratory tract, including the nasal cavity and paranasal sinuses. This type of epithelial tissue may be ciliated or nonciliated at the tissue surface. Note: Pseudostratified ciliated columnar epithelial cells help trap and transport particles brought in through the nasal passages and lungs. Remember: Transitional epithelium, which lines the urinary bladder, ureters, and part of the urethra, makes up specialized tissue that allows for the expansion of an organ with only minimal resistance from the tissue.

In a cardiac tamponade caused by trauma, the pericardial sac fills up with fluid. The increased pressure on the heart prevents the pumping chambers from filling up properly and in turn causes inadequate pumping of blood. The pumping chambers of the heart are anatomically known as: • Vena cavae • Ventricles • Nodes • Atria

Ventricles The adult heart is a hollow, four-chambered muscular organ that is about the size of a closed fist. About two-thirds of the heart'smass is to the left of the body midline. The heart and its peri¬cardium make up the contents of the middle mediastinum. The pericardium is a tough dou¬ble-walled fibrous membranous sac that surrounds the heart. The outer wall of the sac is called the parietal pericardium; the inner wall of the sac is called the visceral pericardium (epi¬cardium). The parietal and visceral pericardia are continuous. This continuity takes place at the points where the major blood vessels enter and leave the heart. In between these walls is the pericardial cavity, which contains serous fluid that minimizes friction as the heart beats. The anterior surface of the heart is also known as the sternocostal surface. The anterior sur¬face shows parts of each of the four chambers of the heart: • Right atrium (RA) I are small and located toward the superior region of the heart and • Left atrium (LA) are separated by the thin, muscular interatrial septum. • Right ventricle (RV) I are larger and are located at the apex of the heart and are sepa- • Left ventricle (LV) I rated by the thick, muscular interventricular septum. Three borders of the heart: • Right border: made up of the right atrium • Inferior border: made up of right atrium, right ventricle, and left ventricle • Left border: made up of the left ventricle The left and right ventricles make up the diaphragmatic surface of the heart. This part rests on the fibrous part of the diaphragm. The left atrium makes up the so-called base of the heart. When the body is in the supine po¬sition (lying on its back), the heart rests on its base, and the apex of the heart (the tip of the left ventricle) projects up and to the left and fits into a depression on the diaphragm.

Function, location, origin, termination of the following: Lateral corticospinal (or crossed pyramidal) Anterior corticospinal (direct pyramidal) Lateral reticulospinal Medial reticulospinal Rubrospinal Vestibulospinal

Voluntary movement, contraction of individual or small groups of muscles, particularly those moving hands, fingers, feet, and toes of opposite side Same as lateral corticospinal except mainly muscles of same side Mainly facilitatory influence on motor neurons to skeletal muscles Mainly inhibitory influence on motor neurons to skeletal muscles Coordination of body movement and posture Mediates the influences of the vestibular end organ and the cerebellum upon extensor muscle tone Lateral white columns Anterior white columns Lateral white columns Anterior white columns Lateral white columns Lateral white columns Motor areas or cerebral cortex opposite side from tract location in cord Motor cortex but on same side as loca- tion in cord Reticular formation, midbrain, pons, and medulla Reticular formation, medulla mainly Red nucleus (of midbrain) Lateral vestibular nucleus (4th ventricle) Lateral or anterior gray columns Lateral or anterior gray columns Lateral or anterior gray columns Lateral or anterior gray columns Lateral or anterior gray columns Lateral or anterior gray columns

Types of Dentin: Location/Chronology, Description Peritubular dentin Intertubular dentin Mantle dentin Circumpulpal dentin Primary dentin Secondary dentin Tertiary dentin

Wall of tubules Between the tubules Outermost layer Layer around outer pulpal wall Formed before completion of apical foramen Formed after completion of apical foramen Formed as a result of injury Highly calcified Highly calcified First dentin formed Dentin formed after mantle dentin Formed more rapidly; is more mineralized than secondary Formed slower and is less mineralized than primary Irregular pattern of tubules

are specialized cells within the alveoli of the lungs that are adapted to produce surfactant. Type I pneumocytes are extremely thin epithelial cells lining the alveoli of the respiratory tree and permit gaseous diffusion with the capillaries.

When foreign objects are aspirated into the trachea, they usually pass into the right primary bronchus because it is larger, straighter, and shorter than the left. It is also in a more direct line with the trachea (important in a dental chair because if a patient swallows an object it tends to lodge in the right bronchus).

what happens when urinary bladder is full

When full, the bladder sends a message to the reflex center in the sacral part of the spinal cord, where it triggers a reflex contraction of the muscle of the bladder and causes the neck of the bladder to relax. This reflex is suppressed until there is an opportunity to relieve the bladder.

CIn which zone of the adrenal gland are mineralocorticoids secreted from? ) • Medulla • Zona glomerulosa • Zona fasciculata • Zona reticularis

Zona glomerulosa The two adrenal glands (also called suprarenal glands) are flattened, somewhat trian-gular-shaped endocrine glands resting upon the superior poles of each kidney at the back of the abdomen. Each gland has an outer part, the cortex, and a core, the medulla. The adrenal cortex is composed of three layers, or zones (endocrine cells are organized into these three areas). 1. Zona glomerulosa -- a thin layer composed of clusters of cells beneath the connec-tive tissue capsule. Cells secrete the mineralocorticoids, primarily aldosterone, which are involved with the maintenance of electrolyte and water balance. 2. Zona fasciculata -- a thick middle layer, the cells are arranged in parallel columns that run at right angles to the surface of the gland. Cells secrete the glucocorticoids, pri-marily cortisol. Small amounts of estrogenic- and androgenic- like substances are also produced. 3. Zona reticularis -- inner layer of cortex, cells are arranged in a network of inter-connecting cords. Secretes small amounts of cortisol and dehydroepiandrosterone (DHEA). Remember: The medulla of the adrenal gland really is modified nervous tissue and func-tions in a manner similar to postganglionic sympathetic cells -- stimulation of the ad¬renal medulla causes the release of large quantities of epinephrine and norepinephrine. The same effects are also caused by direct sympathetic stimulation, except the effects last longer when the medulla secretes the hormones. With or without one or the other (medulla or sympathetic nerves), the organs would still be stimulated.

Which bone anchors the muscles of mastication and facial expression?

Zygomatic bone -- also called the cheekbone or malar bone: The zygomatic bone is situated at the upper and lateral part of the face: this bone forms the prominence of the cheek, part of the lateral wall and floor of the orbit, and parts of the temporal and infratemporal fossae. The zygomatic bone presents a malar and a temporal surface; four processes, the frontosphenoidal, orbital, maxillary, and temporal; and four borders.

urinary bladder

a distensible sac that is situated in the pelvic cavity posterior to the symphysis pubis. The urinary bladder is slightly lower in the female than in the male. It concentrates and serves as a reservoir for urine, which the bladder receives from the kidneys through the ureters and discharges through the urethra.

thrombopoietin

a glycoprotein hormone made and secreted by liver and stimulates precursor cells in bone marrow to become megakaryocytes which make platelets

where are kidneys ureters and urinary bladder all located?

all located retroperitoneally. This means they are located behind the peritoneum, which is the serous membrane lining the walls of the abdominal and pelvic acvities and enclosing the viscera

Site of exit from skull, component and function for the following: Trigeminal: (CN V) V-1 Ophthalmic V-2 Maxillary V-3 Mandibular Abducens (CN VI)

a. Superior orbital fissure Foramen rotundum Foramen ovale Superior orbital fissure b. Bronchial motor (special visceral efferent) General sensory (general somatic afferent) Somatic motor (general somatic efferent) c. Innervates the muscles of mastication: • Masseter • Temporalis • Medial pterygoid • Lateral pterygoid Also innervates: • Mylohyoid • Anterior digastric • Tensor tympani • Tensor veli palatine General sensation to the major part of the head Innervates the lateral rectus muscle

Difference of thymus in adults vs children

adult thymus: blood supply isolated from paranchyma (which is the functioning portion of the gland)...this is called the blood thymus barrier in kids: blood supply is not isolated from the parenchyma

renal papilla of kidneys

apex of pyramids, here the collecting ducts pour into minor calyces

cartilaginous joint and examples

are amphiarthrosis,joined by fibrocartilage and hyaline cartilage. 2 types, synchondroses (primary cartiliginous joint ) which are joined by hyaline cartilage and permit no movement but growth in the length of the bone(epiphyseal plates within long bones and first rib of sternum), and symphyses (secondary cartiliginous joint )which are joined by a plate of fibrocartilage and are slightly movable (pubic symphysis and intervertebral discs)

synovial joints

are freely movable (diarthrodial), with movement limited only by joint surfaces, ligaments, muscles, or tendons. they are characterized by 4 features: articular cartilage, joint cavity, articular (joint) capsule, and synovial membrane

lingual tonsils

are smaller and more numerous. on the posterior portion of the dorsum of the tongue. each has a single crypt. are surrounded by non keratinized stratified squamous epithelium

Type II pneumocytes vs Type I pneumocyte

are specialized cells within the alveoli of the lungs that are adapted to produce surfactant. Type I pneumocytes are extremely thin epithelial cells lining the alveoli of the respiratory tree and permit gaseous diffusion with the capillaries.

fibrous joint and example

are synarthrosis (barely movable or not movable) joined by fibrous CT, 2 types: sutures of skull and syndesmoses (between radius and ulna)

peyers patches

are the "intestinal tonsils", found in small intestine, mainly the iluem.

inner medullary region

arranged into medullary cords which are source of plasma cells. also contain medullary sinuses

some synovial joints have...

articular discs (TMJ and sternoclavicular joint). These discs consist of fibrocartilage. they divide the cavity into 2 seperate cavities

when does yellow marrow begin to form and what happen s to the red marrow

at 7 years old it begins and grows until your an adult at which point red marrow can only be found in the bones of the skull, vertebral column, thoracic cage, girdle bones, and the head of the humerous and femur.

blood enters and drains in spleen how?

at the hilium through the splenic artery and is drained by the splenic vein which joins the superior mesenteric vein to form the hepatic portal vein to the liver

some bitch ass mofo crashed his whip and he goes to the ER and he can nod his head to say yes but cant nod to say no: which joint allows maximum rotational movement of the head about its vertical axis (saying no)

atlantoaxial joint does...it is the synovial articulation between the inferior articulating facets of the atlas (first cervical vertebra) and the superior articulating facets of the axis (second cervical vertebra)

articular (joint) capsule

double layered with outer layer of fibrous CT that encloses the joint

which leukocytes is the least abundant

basophil

submental lymph nodes

behind chin and on mylohyoid muscle. receive lymph from tip of tomgue, floor of mouth beneath tip of tongue, mandibular incisor teeth and associated gingiva, center part of lower lip, and the skin over the chin. the efferent lymph vessels drain into the submandibular and deep cervical nodes

submandibular lymph nodes

between submandibular gland and mandible, recieve lymph from front of scalp, nose, adjacent cheek, upper and lower lip (except the center part), paranasal sinuses, maxillary and mandibular teeth (except the mandibular incisors), anterior two thirds of the tongue (except tip), floor of the mouth and vestibule, and the gingiva. the efferent lymph vessels drain into the deep cervical nodes

splenic pulp

between trabeculae, made of lymphocytes and macrophages

under the microscope RBCs appear as...and what is there lifespan

biconcave discs without nuclei...they also lack mitochondria average lifespan is 120 days

erythrocytes

biconcave, anuclear cells that transport oxygen..made via erythropoiesis stimulated by hormone called erythropoietin

Whats the thymus

bilobed lymphoid organ in superior mediastinum with no lymphatics. its large in newborns, grows until puberty then regresses in adults. main function to develop Tcells

serum

blood plasma without fibrinogen (after coagulation)

what are the components of the lymphatic system

bone marrow, spleen, thymus gland, lymph nodes, tonsils, appendix, peyers patches, lymph, lymphatic vessels

how are the spleen and the thymus similar

both have only efferent lymphatic vessels

where and by what is lymph cleansed

cleansed in the cortical sinuses of the lymph node by macrophages, lymphocytes, and plasma cells

sutures

connected by fibrous CT and found between flat bones of skull

syndesmoses

connected by fibrous CT and occur as the inferior tibiofibular and tympanostapedial syndesmoses

part of blood thats not plasma

consists of formed elements including erythrocytes (RBCs), leukocytes (WBCs) and platelets

urinary system

consists of the kidneys, the ureters, the urinary bladder, and the urethra. This system filters the blood and maintains the volume and chemical composition of the blood.

Respiratory bronchioles

continuing from terminal bronchioles, branch nearer to the alveolar ducts and sacs and have occasional alveoli in their walls. These bronchioles capable of respiring are the first generation of passageways of the respiratory portion of the bronchial tree.

anterior surface of spleen

covered in peritoneum, and enclosed in a fibroelastic capsule that dips into the spleen itself, forming trabeculae. between the trabeculae you have splenic pulp

Examination of a patient with an ulcerative carcinoma of the posterior third of the tongue revealed bleeding from the lesion and difficulty swallowing (dysphagia). The bleeding was seen to be arterial; which of the following arteries was involved?

dorsal lingual artery

Which lymph node groups extend from the base of the skull to the root of the neck

deep cervical nodes

since lymphatic system has no pump, how does lymph move around

depends on contractions of skeletal muscle, valves in lymphatic vessels (lsimilar to those in veins), breathing, and gravity move fluid through body

how does spleen develop?

develops from mesenchymal cells of the mesentary attached to the primitive stomach

which structure leaves each individual lymph node at the hilus

efferent vessels

The most prominent functional component in the tunica media of large arteries is the:

elastic fibers. Key: If the question referred to small arteries, the answer would have been smooth muscle cells.

A 71-year-old woman presents to the dentist with multiple blisters on the oral mucosa. She states that the physician has diagnosed her with bullous pemphigoid (BP), an autoimmune disease in which the body targets certain intercellular junctions. In BP, the junctions that are targeted are those that anchor the basal cells of the epithelia to the underlying basal lamina, causing the epidermis to detach. Which junctions are affected in BP? • Desmosomes • Hemidesmosomes • Adherens junctions

emidesmosome Bricks in a building must be stuck together and also tied somehow to the foundation. Similarly, cells within tissues and organs must be anchored to one another and attached to components of the extracel-lular matrix. Cells have developed several types of intercellular junctions to serve these functions, and in each case, anchoring proteins extend through the plasma membrane to link cytoskeletal proteins in one cell to cytoskeletal proteins in neighboring cells as well as to proteins in the extracellular matrix. An intercellular junction between cells is a desmosome. The desmosome appears to be disc-shaped and can be likened to a "spot weld." Another type of intercellular junction is a hemidesmosome, which involves an attachment of a cell to an adjacent noncellular surface. Important: This type of attachment is present with the gingival epithelium that attaches to the tooth surface (called the junctional epithelium of the epithelial attachment) as well as in that which occurs between nails and nail beds. Note: The clinical condition known as bullous pemphigoid involves the disruption of hemidesmosomes and consequent separation of the epithelium from the basal lamina. Another type of intercellular junction is what is called an adherens junction (also called zonula ad-herens). These junctions share the characteristic of anchoring cells through their cytoplasmic actin fil-aments. There is considerable morphologic diversity among adherens junctions. Those that tie cells to one another are seen as isolated streaks or spots, or as bands that completely encircle the cell. The band-type of adherens junctions is associated with bundles of actin filaments that also encircle the cell just below the plasma membrane. Spot-like adherens junctions help cells adhere to the extracellular matrix. Adherens junctions are thought to participate in folding and bending of epithelial cell sheets.

vestibulocochlear nerve

enters the internal acoustic meatus and remains within the temporal bone, to the cochlear duct (hearing), semicircular ducts, and maculae (balance).

facial nerve and stylomastoid foramen

enters the internal acoustic meatus, the facial canal in the temporal bone, and emerges from the stylomastoid foramen. The stylomastoid foramen lies between the styloid and mastoid processes of the temporal bone.

which is there more of: afferent or efferent vessels?

fewer efferent then afferent per node

joints classified by type of associated CT

fibrous, cartiligenous, and synovial

spleens function

filters blood and removes abnornmal cells (i.e. old RBCs), and makes disease fighting components of immune system (i.e. antibodies and lymphocytes)

tubular portion of kidney...tell me about the process

filtrate from bowmans capsule goes into PCT in cortex where glucose/AA's/metabolites/electrolytes are absorbed from filtrate and brought back into circulation. then filtrate goes to loop of henle where filtrate is concentrated through electrolyte exchange and reabsorption to produce a hyperosmolar fluid..then to DCT where sodium is reabsorbed thanks to aldosterone. then to collecting duct which is distal end of nephron and site of final concentration of filtrate then empties into papillary ducts deep within medulla.

bursa

fluid filled sac lined with synovial membrane. job is to reduce friction (i.e. between a tendon and bone). inflammation of bursa is bursitis

what happens after filtration (kidney)

fluid in tubules of nephron undergo 2 more processes both in the peritubular capillaries: tubular reabsorption and tubular secretion. some blood isnt filteres and passes into the efferent vessels and peritubular capillaries from the tubules by reabsorption often at high rates. waste products are retained and emptied into a collecting tubule, which is discharged to the ureters.

spleen: how its formed and where it lies

formed by reticular and lymphatic tissue. is the largest lymph organ. it lies in the left hypochondriac region of the abdominal cavitiy between the fundus of the stomach and the diaphragm

where would you most liely find yellow bone marrow and whats its function

found in center of ling bones and is a site for fat storage

diarthrosis

freely movable synovial joint

NOTE

from card 274 I just started copying and pasting

lymph node structure

has an outer cortical region and an inner medullary region

what type of cartiliage does the TMJ have

has fibrocartilage, not hyaline

outer cortical region

has germinal centers (nodules) which are source of lymphocytes. also contains subscapular and cortical sinuses

bone marrow stem cells

has pluripotent stem cells which become lymphocytes (then become B cells and mature in bone marrow or T cells which travel from bone marrow to thymus to mature) or phagocytes

medulla of kidney

has renal pyramids that are seperated by renal columns (extensions of renal cortex)

cortex of kidney

holds glomeruli and proximal and distal convoluted tubules. site of blood filtration

granulocyte colony stimulating factor

hormone that stimulates precursor cells in bone marrow to become WBCs (leukocytes)

supporting ligaments

i.e. capsular, extracapsular, and intracapsular ligaments) maintain the normal position of the bones

venous sinusoids

in spleen, along with th power of the spleen to contract provides a method for expelling the contained blood to meet increased circulatory demands

reticuloendothelial tissue

in spleen, does phagocytosis of erythrocytes and cell debris from blood. can also produce foci of hemopoiesis when RBCs are needed

what is a hallmark of lymphatic vessels?

in the upper limb, lymphatic vessels follow the veins

leukocytes

include granulocytes (neutro/eosino/basophils) and agranulocytes (monocytes and lymphocytes)

The structures of the upper respiratory tract

include the nose, mouth, nasopharynx, oropharynx, laryngopharynx, and larynx. Besides warming and humidifying inhaled air, these structures provide for taste, smell, and the chewing and swallowing of food.

Which fossa has no bony inferior or posterior boundary?

infratemporal fossa

where does the right lymphatic duct drain

into the junction of the right internal jugular and right subclavian veins (which is actually the beginning of the right brachiocephalic vein)

Bone in the mandible develops by:

intramembranous ossification. The first evidence of bone ossification (bone formation) occurs around the eighth week of prenatal development. Bones develop either through endochondral ossification (going through a cartilaginous stage) or through intramembranous ossification (forming directly as bone). The distinction between endochondral and intramembranous formation rests on whether a cartilage model serves as the precursor of the bone (endochondral ossification) or whether the bone is formed by a simpler method, without the intervention of a cartilage precursor (intramembranous ossification).

blood

is 8% of body weight, 4-6 liters, pH 7.35-7.45, 55% plasma and 45% formed elements

pterygopalatine fossa

is a cone-shaped paired depression deep to the infra-temporal fossa. The pterygopalatine fossa located between the pterygoid process and the maxillary tuberosity, close to the apex of the orbit. This fossa contains the maxillary artery and nerve and their branches arising here, including the infraorbital and sphenopalatine arteries, the maxillary division of the trigeminal nerve and branches, and the pterygopalatine ganglion. The pterygopalatine fossa communicates laterally with the infratemporal fossa through the pterygomaxillary fissure, medially with the nasal cavity through the sphenopalatine foramen, superiorly with the skull through the foramen rotundum, and anteriorly with the orbit through the inferior orbital fissure.

acoustic neuroma

is a tumor involving the vestibulocochlear nerve as it exits the cranial cavity. Because this tumor compresses surrounding structures or invades nearby tissues, in addition to hearing loss and equilibrium problems, a patient would most likely also demonstrate ipsilateral (same-sided) facial paralysis

gomphosis

is an examle of synarthrosis. its the joint that binds the teeth to the bony sockets (dental alveoli) in the mandible and maxilla

synovial fluid

is clear, thick fluid secreted by the synovial membrane, which fills the joint capsule and lubricates the articular cartilage at the ends of the articulating bones

synovial joint and examples

is diarthroidal, permit a degree of free movement , is a joint capsule containing a synovial membrane that secretes a synovial fluid. most joints such as TMJ are synovial

white pulp

is inside red pulp of spleen, has little lumps of lymphoid tissue where it provided lymphocytes and plasma cells where Abs are made (cellular and humoral defense)

optic canal

is located posteriorly in the lesser wing of the sphenoid. It communicates with the middle cranial fossa. It transmits the optic nerve and the ophthalmic artery.

cricothyrotomy

is preferable to tracheostomy for non-surgeons in emergency respiratory obstructions. In this procedure, an incision is made through the skin and cricothyroid membrane for the relief of acute respiratory obstruction.

The injection site for the inferior alveolar nerve block

is probed with a cotton tip applicator at the depth of the pterygomandibular space on the medial surface of the ramus. The needle is inserted into the tissues of the pterygomandibular space until the mandible is contacted. The needle is withdrawn 1 mm from the tissues to protect the periosteum, and then the injection is administered.

Laryngopharynx

is the most inferior division of the pharynx; the laryngopharynx extends from the hyoid bone to the opening of the esophagus. The laryngopharynx is lined with stratified squamous epithelium. extends from the oropharynx above to the larynx and esophagus. The laryngopharynx also serves as a passageway for food and air. Air entering the laryngopharynx goes to the larynx while food goes to the esophagus.

Nasopharynx

is the most superior division of the pharynx. It is inferior to the sphenoid bone and lies at the level of the soft palate. The pharynx is lined with ciliated pseudostratified epithelium (respiratory epithelium). The nasopharynx has four openings: two auditory (eustachian) tubes: each opening out of a lateral wall and connecting with the middle ear (tympanic cavity), and two openings of the posterior nares (choanae). The soft palate and uvula form the anterior wall of the nasopharynx. Note: The tensor veli palatini and the levator veli palatini muscles prevent food from entering the nasopharynx.

renal pelvis of kidney

joins with ureters and receives urine through the calyces

synovial joint characterized by 4 features

joint (synovial) cavity, articular cartilage, synovial membrane, and articular capsule

where does the thoracic duct empty into

junction of the left internal jugular and left subclavian veins (which is actually the beginning of the left brachiocephalic vein)

the thoracic duct usually drains into the...

junction of the left internal jugular and subclavian veins

Jugular foramen

lies between the lower border of the petrous part of the temporal bone and the condylar part of the occipital bone. The jugualr foramen transmits the following structures: the internal jugular vein, and the glossopharyngeal, vagus and spinal accessory nerves.

At the gymnastics center, a 22-year-old male doing flips on the trampoline lands incorrectly on his ankle and dislocates it. In the emergency room, the physician must provide traction to replace the ankle, and the procedure is without incident. The patient is told that although there are no fractures the bands of fibrous connective tissue that connect bone to bone are almost definitely torn. These bands are called: • Tendons • Bursae • Ligaments • Menisci

ligaments Ligaments are dense, strong, flexible bands of fibrous connective tissue that tie bones to other bones. Ligaments that connect the joint ends of bones either limit or facilitate move¬ment. Ligaments also provide stability. Tendons are strong, flexible bands of fibrous con¬nective tissue that attach muscles to the fibrous membrane that covers bones (periosteum). Tendons move bones when skeletal muscles contract. Important: When a tendon or ligament is attached to the bone, the attaching fibers are called Sharpey's fibers. They are periosteal collagen fibers that penetrate the bone ma¬trix, binding the periosteum to the bone. Remember: The periodontal ligament contains collagen fibers that are inserted on one side in the cementum and on the other side in alveolar bone. The ends of these collagen fibers are Sharpey's fibers. Bursae are small, synovial, fluid-filled sacs located around joints at friction points be-tween tendons, ligaments, and bones. Bursae act as cushions. 1. A fasciculus is a bound group of individual muscle fibers. The fasciculi are the bundles of muscle fibers composing a muscle. In turn, each muscle is sur¬rounded by a connective tissue called fascia. 2. The fascia secures the muscle to a tendon. 3. An aponeurosis is a sheetlike tendon. 4. Menisci are crescent-shaped interradicular fibrocartilages in certain joints, in¬cluding the knee.

urinary system lined with... genital and urinary system are controlled by which nerves

lined with transitional epithelium. are supplied with parasympathetic fibers from the pelvic splanchnic nerves.

what is lymph composed of

liquid part thats like blood plasma and WBCs (mostly lymphocytes) and a few RBCs

plasma

liquid portion of blood is 91% water...the 9% is various things including 7% proteins (albumin>globulin>fibrinogen) and 2% other solutes (metabolic end products, food material, respiratory gases, hormones etc, ions)

pharyngeal tonsils

located at posterior wall of nasopharynx. peak of development during childhood, and when enlarged are called adenoids. theyre surrounded by CT and by ciliated pseudostratified columnar epithelium (respiratory epithelium). they have NO crypts

palatine tonsils

located at posterolateral walls of throat, one on each side. reach max size during early childhood, but after puberty get much smaller. they enlarge alot when a person has "sore throat". they have many crypts, lymphoid follicles, but NO sinuses. surrounded by CT and non-keratinized, stratified squamous epithelium.

kidney

located at the back of the abdomen at the lower level of the ribs. function is forming urine and maintaining homeostasis. they lie on eaither side of lumbar spine and lie retroperitoneally (external to the peritoneal lining of the abdomial cavitiy) in front of the muscles attached to the vertebral column. each kidney surrounded by fibrous renal cavity and supported by adipose capsule. each kidney gets blood from renal artery, a branch of the abdominal aorta

mandibular foramen

located on the medial surface of the ramus of the mandible just below the lingula, midway between the anterior and posterior borders of the ramus. The foramen leads into the mandibular canal, which opens on the lateral surface of the body of the mandible at the mental foramen.

path of lymph

lymph absorbed from tissue into lymph capillaries, then afferent vessels enter on convex surface of node, cortical sinuses of lymph node, efferent vessels, concave hilum, efferent collecting vessels, lymph trunks, and empties into either thoracic duct (drains mostly here and to left subclavian vein) or right lymphatic duct (drains right upper portion of body and goes to right subclavian vein).

arranged into medullary cords which are source of plasma cells. also contain medullary sinuses

lymph from a region drains into a primary or regional node which drains into a secondary or central node

thromboxane A2

made by activated platelets has prothrombic properties, stimulating activation of new patelets and increasing platelet aggregation

red bone marrow...where is it produced and what does it produce

made in cavities in the cranial bones, vertebrae, ribs, syernum, and the end of long bones. produces erythrocytes, leukocytes, and thrombocytes in a process called hemopoiesis. it starts with a precursor cell called hemocytoblasts (pluripotent stem cells) which give rise to various progenator cells which give rise to many other elements like proerythrocytes which become erythrocytes and megakaryocytes which become platelets.

renal corpuscle of kidney

made of glomerulus which is surrounded by bowmans capsule (collects filtrate). its the site of filtration producing cell and protein free filtrate which then goes to the PCT

synovial membrane

makes synovial fluid, and found on both bursa and articular cartilage

Which artery supplies the muscles of mastication, the maxillary and mandibular teeth, the palate, and almost all of the nasal cavity?

maxillary artery

Which branch of the internal carotid artery is most frequently implicated in a stroke?

middle cerebral artery

some dude has a calcium oxalate build up in the renal pappilla which would block filtrate flow into:

minor calyx

which leukocyte is the predominant cell type in pus, and is known as the hallmark of acute inflammation becasue of its fast immune response

neutrophil

tonsils

part of secondary immune system. lies in respiratory and alimentary canals and when it notices something foreign from food or air it stimulates B cells to make Abs, mostly IgA

where do lymph nodes generally occur

occur in clusters mainly in armpits, groin, lower abdomen, and sides of neck

what does the right lymphatic duct drain

only the lymph from the right arm, right thorax, and right side of the head)

The nasal cavity

opens on the face through the nostrils or nares and communicates with the nasopharynx through two posterior openings called the choanae. The area below each concha (superior, middle, and inferior) is referred to as a meatus. The nasal cavity receives innervation from the olfactory nerve (CN I) and branches of the trigeminal nerve (CN V). The nasal cavity's blood supply is mainly from the sphenopalatine branch of the maxillary artery. The nasal cavity also receives blood from the anterior ethmoidal branch of the ophthalmic artery and the septal branch of the superior labial branch of the facial artery.

best way to distinguish palatine from pharyngeal tonsils

pharyngeal has respiratory epithelium and palatine has non-keratinized, stratified squamous epithelium.

3 sets of tonsils

pharyngeal, palatine, and lingual

platelet plug

platelets adhere to collagen, release ADP and other chemicals from secretory vesicles that induce change to platelet surface, making platelets become sticky...then eventually a plug formes with a shitton of platelets sticking to each other

3 major functions of spleen are handled by

reticuloendothelial tissue, venous sinusoids, and white pulp

functions of lymphatic system

return tissue fluid to bloodstream (fluid in lymph capillaries is called lymph), transport absorbed fats (lymph cappilaries called lacteals in small intestine do this), provide immunological defenses against disease causing agents

interesting fact about the location of the kidneys

right kidney is slightly lower then left one due to a large size of right lobe of liver

Identify the following areas of a developing tooth bud on the schematic drawing below.

see pic 305

which components of lymphatic system do NOT have numerous afferent vessels entering them like the lymph node?

spleen, thymus, palatine/pharyngeal tonsils

Which salivary glands does the facial artery supply?

submandibular gland

external carotid artery

supplies structures within the neck, face, and scalp, and also supplies the maxilla and tongue. As with the internal carotid artery, the external carotid artery begins at the upper border of the thyroid cartilage (i.e., at the termination of the common carotid artery and the carotid sheath). The external carotid artery terminates within the parotid gland, just behind the neck of the mandible, where the artery gives off two fmal branches, the superficial temporal and the maxillary arteries. Note: At its origin, where pulsations can be felt, the external carotid artery lies within the carotid triangle.

classes of articulations (joints)

synarthrosis, amphiarthrosis, diarthrosis

most joints in the body are

synovial joints classified as diarthroses (means freely movable).

plasmapharesis

taking blood and seperating the liquid portion then returning the liqiud (plasma) portion back into blood circulation. Method is used to treat various diseases

the thoracic duct ascends through...

the aortic opening in the diaphragm, on the right side of the descending aorta. it also ascends between the aorta and the azygos vein in the thorax (btw it ascends via valves)

thoracic cavity

the thoracic cavity is surrounded by the ribs and chest muscles. It's subdivided into the pleural cavities, each of which contain a lung, and the mediastinum. The mediastinum is further divided into four areas. The middle mediastinum contains the heart and pericardial sac; the anterior, posterior, and superior areas are named according to their positions relative to the middle mediastinum.

The zygomatic bone articulates with four bones:

the frontal, sphenoidal, temporal (to form the zygomatic arch), and maxilla. Above the zygomatic arch is the temporal fossa, which is filled with the temporalis muscle. Attached to the lower margin of the zygomatic arch is the masseter muscle. Note: The temporalis muscle passes medial to the zygomatic arch before the muscle inserts into the coronoid process of the mandible. The temporal fossa is a shallow depression on the side of the cranium bounded by the temporal lines and terminating below the level of the zygomatic arch. The infratemporal crest of the greater wing of the sphenoid bone separates the temporal fossa from the infratemporal fossa below it. Important: The temporal and infratemporal fossae communicate with each other deep to the zygomatic arch. The pterygopalatine fossa communicates laterally with the infratemporal fossa through the pterygomaxillary fissure, medially with the nasal cavity through the sphenopalatine foramen, superiorly with the skull through the foramen rotundum, and anteriorly with the orbit through the inferior orbital fissure.

if you need to perform a splenectomy, where do you cut?

the left hypochondrium of the abdominal cavity between the stomach and the diaphragm

the medial wall or nasal septum is formed by the

the medial wall or nasal septum is formed by the perpendicular plate of the ethmoid bone, the vomer bone, and the septal cartilage. The rest of the framework of the nose consists of several plates of cartilage, specifically, the lateral nasal cartilage and the greater and lesser alar cartilage. The cartilage is held together by fibrous connective tissue.

celiac plexus

the nerves to the spleen accompany the splenic artery and are derived from the celiac plexus

Blood is supplied to the brain, face, and scalp via two major sets of vessels:

the right and left common carotid arteries and the right and left vertebral arteries. The right common carotid arises from the brachiocephalic trunk, while the left common carotid arises from the aortic arch directly. The common carotid lies within the carotid sheath and runs upwards in the neck to the superior border of the thyroid cartilage. Here it divides into two pairs of blood vessels, the external and internal carotid arteries. The external carotid arteries supply the face and scalp with blood. The internal carotid arteries divide further in the middle cranial fossa into the anterior and middle cerebral arteries, which supply blood to the anterior three-fifths of cerebrum, except for parts of the temporal and occipital lobes. The vertebrobasilar arteries supply the posterior two-fifths of the cerebrum, part of the cerebellum, and the brain stem.

articular cartilage

thin layer of hyaline cartilage that covers the smooth articular bone surfaces and has no blood vessels or nerves.

what develops immature Tcells into immunocompetent Tcells

thymus

The lower respiratory tract structures are the

trachea, bronchi, and lungs. Bronchi branch into bronchioles, which in turn branch into lobules. The lobule includes the terminal bronchioles and alveoli. A mucous membrane containing hair-like cilia lines the lower tract. Functionally, the lower tract is subdivided into conducting airways (the trachea and the primary, lobar, and segmented bronchi) and alveoli, the sites of gas exchange

ureters

transport urine from the pelvis of the kidney to the base of the urinary bladder. Because the left kidney is higher than the right, the left ureter is usually slightly longer than the right. The ureters are narrowest where they originate, at the renal pelvis (ureteropelvic junction). Note: Filling of the bladder constricts the ureters at the ureterovesical junction, where they enter the bladder. Peristaltic waves, occurring about one to five times each minute, move urine through the ureters.

what do peyers patches and tonsils have in common

what do peyers patches and tonsils have in common