bhsc 1200 final exam
explain the difference between conducting and respiratory zones
-conducting zone: a series of interconnecting cavities and tubes both outside and within the lungs; nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles; filter, warm, and moisten air and conduct it into the lungs -respiratory zone: tubes and tissues within the lungs where gas exchange occurs; respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli; main sites of gas exchange between air and blood
functions of large intestine
-haustral churning, peristalsis, and mass peristalsis drive the contents of colon into rectum -bacteria in large intestine covert proteins to amino acids, break down amino acids, and produce some B vitamins and vitamin K -absorption of some water, ions, and vitamins -formation of feces -defecation
corpus callosum
a broad band of white matter containing axons that extend between the hemispheres and connect them
inferior vena cava
carries blood from lower regions of the body to right atrium
pulmonary arteries
carry deoxygenated blood out of the right ventricle and into the lungs
pulmonary veins
carry the oxygenated blood from the lungs into the left atrium of the heart
clinical significance of dermatomes
knowing which spinal cord segments supply each dermatome makes it possible to locate damaged regions of the spinal cord
vocal folds
-component of larynx -principle structures of voice production -nonkeratinized stratified squamous epithelium
functions of GnRH
-gonadotropin releasing hormone -stimulates gonadotrophs on anterior pituitary to increase their secretion of the two gonadotropins: luteinizing hormone and follicle stimulating hormone
structure of uterine wall
- 3 layers: perimetrium, myometrium, and endometrium -perimetrium: outer layer; simple squamous epithelium and areolar connective tissue; laterally, becomes broad ligament; anteriorly, covers urinary bladder and forms vesicouterine pouch (a shallow pouch); posteriorly, covers the rectum and forms rectouterine pouch (shallow pouch between rectum and uterus) -myometrium: middle layer; three layers of smooth muscle fibres that are thickest in the fundus and thinnest in the cervix; thicker middle layer is circular; inner and outer layers are longitudinal or oblique; coordinated contractions of myometrium in response to oxytocin from the posterior pituitary during childbirth and labor help expel the fetus from the uterus -endometrium: inner layer; highly vascularized; 3 components = innermost layer composed of simple columnar epithelium lines the lumen, underlying endometrial stroma (thick region of lamina propria), and endometrial glands develop as invaginations of the luminal epithelium and extend almost to the myometrium; divided into 2 layers = stratum functionalis (lines uterine cavity and sloughs off during menstruation) and stratum basalis (permanent and gives rise to new stratum functionalis after every menstruation)
composition and function of saliva
-99.5% water and 0.5% solutes (ions = sodium, potassium, chloride, bicarbonate, phosphate, and dissolved gasses, IgA, mucus) -water in saliva provides a medium for dissolving foods so that they can be tasted by gustatory receptors and so that digestive reactions can begin -chloride ions in saliva activate salivary amylase which starts the breakdown of starch in the mouth -bicarbonate and phosphate ions buffer acidic foods that enter the mouth so saliva is slightly acidic (6.35-6.85) -mucus lubricates food
alpha cells
-A cells -constitute about 17% of pancreatic islets -secrete glucagon
beta cells
-B cells -constitute about 70% of pancreatic islets -secrete insulin
explain Boyle's law and the relationship between lung volume and pressure
-Boyle's law: the volume of gas varies inversely with pressure, assuming that temperature remains constant -air moves into the lungs when the air pressure inside the lungs is less than the air pressure in the atmosphere; air moves out of the lungs when the air pressure inside the lungs is greater than the air pressure in the atmosphere
somatic nervous system vs autonomic nervous system neurotransmitter effects
-SNS: all somatic motor neurons release ACh; effect is always stimulatory -ANS: preganglionic fibres release ACh; postglanglionic fibres release NE (SANS) or ACh (PANS) at effectors; effect is either stimulatory or inhibitory, depending on type of receptors
describe how cerebrospinal fluid is circulated
-CSF formed in the choroid plexuses of each lateral ventricle flows into the third ventricle through two narrow, oval openings (interventricular foramina); more CSF is added by the choroid plexus in the roof of the third ventricle -fluid then flows through the aqueduct of the midbrain, which passes through the midbrain, and into the fourth ventricle -choroid plexus of the fourth ventricle contributes more CSF -CSF enters subarachnoid space through three openings in the roof of the fourth ventricle: a single median aperture, and paired lateral apertures (one on each side) -CSF then circulates in the central canal of the spinal cord and in the arachnoid space around the surface of the brain and spinal cord
systemic vascular resistance
-aka total peripheral resistance -all of the vascular resistances offered by the systemic blood vessels -larger blood vessels have smaller resistance; smaller blood vessels has greater resistance -centre for regulation of SVR is the vasomotor center in the brain stem
discuss the role of intracellular proteins in establishing the resting membrane potential
-ECF is rich in Na+ and Cl-; ICF is rich in K+ -plasma membrane has more K+ leak channels than Na+ leak channels so the inside of membrane becomes increasingly negative as more K+ leave the cell than Na+ enter -this is why the resting membrane potential is negative
classify the organs of the digestive system as being part of the GI tract or an accessory organ
-GI tract: mouth, pharynx, esophagus, stomach, duodenum, transverse colon, jejunum, descending colon, ascending colon, ileum, cecum, sigmoid colon, appendix, rectum, anal canal, anus -accessory organ: teeth, tongue, salivary glands, liver, gallbladder, pancreas
characteristics and function of oligodendrocytes
-branched cells -processes wrap CNS nerve fibres, forming insulating myelin sheaths thicker nerve fibres
transportation of O2 and CO2 in the blood
-O2: carried on hemoglobin -CO2: carried on hemoglobin; HCO3- in plasma; CO2 dissolved directly
relate the timing of the heart sounds to ECG waves and the phases of the cardiac cycle
-S1 (lubb): caused by blood turbulence associated with closure of the AV valves soon after ventricular systole begins -S2 (dupp): caused by blood turbulence associated with closure of the SL valves at the beginning of ventricular diastole
somatic nervous system vs autonomic nervous system efferent pathways and ganglia
-SNS: cell body is in CNS; a single, thick myelinated group A axon extends in spinal or cranial nerves directly to skeletal muscle -ANS: pathway uses a two-neuron chain: 1) preganglionic neuron = cell body in CNS with thin, lightly myelinated preganglionic axon extending to ganglion, 2) postganglionic neuron = cell body synapses with preganglionic axon in autonomic ganglion with nonmyelinated postganglionic axon that extends to effector organ
target, regulation, and function of epinephrine and norepinephrine
-adrenal medulla hormones -target: heart, blood vessels, lungs, reticular formation -regulation: sympathetic preganglionic neurons release acetylcholine, which stimulates secretion -function: enhance effects of sympathetic division of autonomic nervous system during stress
define absolute and relative refractory periods and explain their significance
-absolute refractory period = when voltage-gated Na+ channels open, neuron cannot respond to another stimulus; time from opening of Na+ channels to resetting of the channels; ensures that each AP is an all-or-none event; enforces one-way transmission of nerve impulses -relative refractory period = period of time during which a second AP can be initiated, but only by a larger-than-normal stimulus; coincides with the period when the voltage-gated K+ channels are still open after inactivated Na+ channels have returned to their resting state significance: act as a protective mechanism so we can't have multiple AP constantly firing
neurotransmitter: endocannabinoids
-act at same receptors as THC (active ingredient in marijuana); most common G protein-linked receptors in brain -lipid soluble -synthesized on demand -believed involved in learning and memory -may be involved in neuronal development, controlling (promoting) appetite, and suppressing nausea
neurotransmitter: purines
-adenosine triphosphate -adenosine: potent inhibitor in brain; caffeine blocks adenosine receptors -act in both CNS and PNS -produce fast or slow responses -induce Ca2+ influx in astrocytes
target, regulation, and function of mineralocorticoids (aldosterone)
-adrenal gland hormone -target: kidney, parotid, colon -regulation: increased blood K+ level and angiotensin II stimulate secretion -function: increase blood Na+ and water; decrease blood level of K+
target, regulation, and function of glucocorticoids (cortisol)
-adrenal gland hormone -target: pituitary gland -regulation: ACTH stimulates release; corticotropin-releasing hormone (CRH) promotes ACTH secretion in response to stress and low blood levels of glucocorticoids -function: increase protein breakdown, stimulate gluconeogensis and lipolysis, provide resistance to stress, dampen inflammation, depress immune responses
paranasal sinuses
-air-filled cavities lined with mucous membrane -produce and drain mucous; resonating chambers for sound -located in the bones of the skull -4 sinuses: frontal, ethmoid, sphenoid, maxillary
describe the routes of solute and water reabsorption
-along renal tubules, tight junctions surround and join neighbouring cells to one another; apical membrane contacts the tubular fluid and basolateral membrane contacts interstitial fluid -paracellular reabsorption: fluid leaks between the cells; tight junction in cells of PCT are leaky and permit some reabsorbed substances to pass between cells into peritubular capillaries -transcellular reabsorption: substance passes from the fluid in the tubular lumen through the apical membrane of a tubule cell, across the cytosol, and out into interstitial fluid through the basolateral membrane
glomerular filtration rate
-amount of filtrate formed in all renal corpuscles of both kidneys each minute -125 mL/min in males; 105 mL/min in females -if too high: needed substances may pass so quickly through the tubules that they are not reabsorbed and instead lost in the urine -if too low: nearly all filtrate may be reabsorbed and certain waste products may not be adequately excreted
role of angiotensin II and natriuretic peptide in GFR regulation
-angiotensin II: reduces GFR; potent vasoconstrictor that narrows both afferent and efferent arterioles and reduces renal blood flow -natriuretic peptide: increases GFR; secreted by cells in the atria of the heart in response to stretching (i.e. when blood volume increases); by causing relaxation of the glomerular mesangial cells, ANP increases capillary surface area available for filtration
identify the posterior, lateral, and anterior white columns
-anterior and posterior gray horns divide the white matter into these columns -each column contains distinct bundles of axons having a common origin or destination and carrying similar information
frontal lobe
-anterior part of brain -functions in motor function, problem solving, memory, language, judgement, social and sexual behaviour, and impulse control
target, regulation, and function of adrenocorticotropic hormone (corticotropin)
-anterior pituitary -target: adrenal cortex -regulation: corticotropin-releasing hormone (CRH) from the hypothalamus stimulates secretion of ACTH, and stress-related stimuli (i.e. low blood glucose, physical trauma, interleukin-1) can stimulate secretion of ACTH; glucocorticoids inhibit CRH and ACTH release via negative feedback -function: stimulate secretion of glucocorticoids (mainly cortisol) by adrenal cortex
target, regulation, and function of growth hormone (somatotropin)
-anterior pituitary -target: liver and other tissues -regulation: 1) GHRH is secreted from hypothalamus; causes include hypoglycaemia, decreased blood levels of fatty acids, increased blood levels of amino acids, sympathetic activity, deep sleep 2) GHRH enters the hypophyseal portal system and flows to the anterior pituitary, where it stimulates somatotrophs to secrete GH 3) GH acts directly on various cells to promote certain metabolic reactions (ex. in liver, bone, skeletal muscle, cartilage, it is converted to IGFs to promote growth) 4) elevated levels of GH and IGFs inhibit release of GHRH and GH 5) GHIH is secreted from hypothalamus; causes include hyperglycaemia, increased blood levels of fatty acids, decreased blood levels of amino acids, obesity, aging 6) after being secreted, GHIH enters the hypophyseal portal system and flows to the anterior pituitary, where it prevents the somatotrophs from secreting GH by interfering with the singling pathway used by GHRH -function: stimulates liver, muscle, cartilage, bone, and other tissues to synthesize and secrete IGFs, which in turn promote growth of body tissues; GH acts directly on target cells to enhance lipolysis and decrease glucose uptake
target, regulation, and function of follicle-stimulating hormone
-anterior pituitary -target: ovary and testis -regulation: gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates FSH release; release of GnRH and FSH is suppressed by estrogen in females and testosterone in males through negative feedback systems (no gonadotropin-inhibiting hormone) -function: in females = initiates development of oocytes and induced ovarian secretion of estrogens; in males = stimulates testes to produce sperm
target, regulation, and function of luteinizing hormone
-anterior pituitary -target: ovary and testis -regulation: secretion controlled by GnRH, as in FSH -function: in females = stimulates secretion of estrogens and progesterone, ovulation, and formation of corpus luteum; in males = stimulates testes to produce testosterone
target, regulation, and function of thyroid-stimulating hormone (thyrotropin)
-anterior pituitary -target: thyroid gland -regulation: thyrotropin-releasing hormone (TRH) from the hypothalamus controls TSH secretion; high levels of T3 and T4 inhibit secretion of TRH; there is no thyrotropin-inhibiting hormone -function: stimulates synthesis and secretion of thyroid hormones by thyroid gland
pituitary gland structures
-anterior pituitary: accounts for 75% of weight of gland; epithelial tissue; consists of 2 parts = pars distalis and pars tuberalis -posterior pituitary: neural tissue; consists of 2 parts = pars nervosa and the infundibulum -infundibulum: a stalk attaching the pituitary gland to the hypothalamus -hypophyseal portal system: hormones carried by this system allow communication between the hypothalamus and anterior pituitary and establish an important link between the nervous and endocrine system -hypophyseal fossa: the deepest part of the sella turcica of the sphenoid bone; holds the pituitary gland
temporal lobe
-anterior, lateral, inferior part of the brain -primary auditory cortex
location, structure, and function of semilunar valves
-aortic valve (left ventricle and aorta) and pulmonary valve (right ventricle and pulmonary artery) -made up of three crescent moon-shaped cusps -SL valves allow ejection of blood from the heart into arteries but prevent backflow of blood into the ventricles -ventricles contract, pressure builds up within chambers- semilunar valve opens when pressure in ventricles exceeds the pressure in the arteries, permitting ejection of blood from the ventricles into the pulmonary trunk and aorta -ventricles relax, blood starts to flow back toward the heart- backflowing blood fills the valve cusps which causes free edges of SL valves to contact each other tightly and close the opening between the ventricle and artery
ventilation
-breathing -flow of air into or out of the lungs -air flows between the atmosphere and the alveoli of the lungs because of alternating pressure differences caused by contraction and relaxation of respiratory muscles -rate of airflow and amount of effort needed for breathing are influenced by alveolar surface tension, compliance of the lungs, and airway resistance
filum terminale
-arises from the conus medullaris -extension of the pia mater that extends inferiorly, fuses with the arachnoid mater and dura mater -anchors the spinal cord to the coccyx
compare the structure and function of arteries, arterioles, metarterioles, capillaries, venules, and veins
-arteries: carry blood away from the heart to other organs; large, elastic arteries leave the heart and divide into medium-sized, muscular arteries that divide into smaller arteries, which then divide into arterioles -arterioles: smaller arteries; branch into tissue, becoming capillaries -metarteriole (capillaries): thin walls; exchange of substances between the blood and body tissues -venules: groups of capillaries within a tissue; form veins -veins: carry blood from the body back to the heart
discuss the pressure and changes that occur during the cardiac cycle
-atrial contraction: volume increases; pressure increases -isovolumetric contraction: opening of aortic valve; no change in volume; left ventricular pressure increases; aortic pressure increases; left atrial pressure increases slightly -ventricular ejection: volume drops; aortic pressure increases then decreases; left ventricular pressure increases then decreases; left atrial pressure decreases, then increases slightly -isovolumetric relaxation: no change in volume; aortic pressure increases, then decreases; left ventricular pressure decreases; no change in left atrial pressure -ventricular filling: increase in volume; aortic pressure drops; no change in left atrial pressure; no change in left ventricular pressure
AV bundles
-atrioventricular bundle; bundle of His -only site where action potentials can conduct from the atria to the ventricles; everywhere else, the fibrous skeleton of the heart electrically insulates the atria from the ventricles
AV node
-atrioventricular node -located in the interatrial septum, just anterior to the opening of the coronary sinus
location and function of pacemaker cells
-autorhythmic fibres in SA node of right atrial wall, inferior and lateral to opening of the superior vena cava -functions: i) act as pacemaker by setting the rhythm of electrical excitation that causes contraction of the heart, ii) form the cardiac conduction system (network of specialized cardiac muscle fibres that provide a path for each cycle of cardiac excitation to progress through the heart)
structural and functional characteristics of cardiac muscle
-autorhythmic; self-excitatory; involuntary -contracts about 100 times a minute -has intercalated discs -striated -single nucleus -branched fibres
mean arterial pressure
-average blood pressure in arteries -roughly one-third of the way between diastolic and systolic pressures -MAP = diastolic BP + 1/3 (systolic BP - diastolic BP)
describe how bile is stored and modified in the gallbladder
-bile enters gallbladder through hepatic and cystic ducts -active transport of Na+ removes water and electrolytes
adrenergic receptors
-bind both norepinephrine and epinephrine -two main types: alpha receptors and beta receptors which are found in visceral effectors innervated by most sympathetic postganglionic axons -further classified into a1, a2, B1, B2, B3 based on the specific responses they elicit and by their selective binding of drugs that activate or block them
pulmonary arteriole
-blood flows from arterioles into capillaries in the lungs -carry deoxygenated blood
discuss pressures that regulate the movement of fluids between capillaries and interstitial spaces
-blood hydrostatic pressure (BHP): pressure that water in the blood plasma exerts against blood vessels; ~35mmHg at arterial end and ~16mmHg at venous end of capillary; opposing pressure of interstitial fluid is called interstitial fluid hydrostatic pressure (IFHP) and pushes fluid from interstitial spaces into capillaries -interstitial fluid osmotic pressure (IFOP): pulls fluid out of capillaries into interstitial fluid; very small (~0.1-5mmHg) because there is very little protein in interstitial fluid; opposes blood colloid osmotic pressure (BCOP) which is a force caused by the colloidal suspension of large plasma proteins (~26mmHg) NFP = (BHP+IFOP) [pressures that promote filtration] - (BCOP+IFHP) [pressures that promote reabsorption] at arterial end = 10mmHg at venous end = -9mmHg
role of sympathetic nervous system in GFR
-blood vessels in kidneys supplies by sympathetic ANS fibres that release NE -NE causes vasoconstriction through activation of alpha 1 receptors, which are found in smooth muscle fibres of afferent arterioles -at rest, sympathetic stimulation is low, afferent and efferent arterioles are dilated, renal auto regulation of GFR prevails -with moderate sympathetic stimulation, both afferent and efferent arterioles constrict to the same degree; blood flow into and out of the glomerulus is restricted to the same extent, lowering GFR slightly -with greater sympathetic stimulation (i.e. exercise or hemorrhage), vasoconstriction of afferent arterioles predominates; blood flow into glomerular capillaries is greatly decreased and GFR drops; lowering of renal blood flow has two consequences: 1) reduces urine output which helps conserve blood volume, and 2) permits greater blood flow to other tissues
relate the structure of the nasal cavity to its function
-bony and cartilaginous framework of the nose help keep the vestibule and nasal cavity patent, allowing air to enter and exit -coarse hairs in vestibule help filter out large dust particles
compare cranial and spinal meninges
-both have three meninges (dura mater, arachnoid mater, pia mater) -cranial dura mater has two layers: periosteal layer (outer) and meningeal layer (inner)
explain the difference between a bronchopulmonary segment and a respiratory lobule
-bronchopulmonary segment: segment of lungs that each bronchus supplies; divides into many small pulmonary lobules -respiratory lobule: where the bronchiole branches to the terminal bronchiole and then respiratory bronchioles, wrapped in lymphatics and blood vessels
describe the location of the thyroid gland
-butterfly shaped -inferior to the larynx (voice box) -composed of right and left lateral lobes, one on each side of the trachea, connected by an isthmus anterior to the trachea
neurotransmitter: biogenic amines
-catecholamines and indolamines -catecholamines: dopemine, norepinephrine (NE), and epinephrine; synthesized from amino acid tyrosine -indolamines: serotonin and histamines; serotonin synthesized from amino acid tryptophan; histamine synthesized from amino acid histidine -broadly distributed in the brain; plays roles in emotional behaviours and biological clock -some released by ANS motor neurons (especially NE) -imbalances associated with mental illness
structure of large intestine
-cecum: a small pouch hanging inferior to the ileocecal valve; ~6 cm long; open end merges with colon -colon: divided into four portions; ascending colon = ascends on the right side of the abdomen, reaches the inferior surface of the liver, and turns abruptly to the left to form the right colic flexure; transverse colon = continuation of ascending colon across the abdomen to the left side; curves beneath the inferior end of the spleen forming the left colic flexure; descending colon = continuation of transverse colon ending at level of iliac crest; sigmoid colon = begins near the left iliac crest, projects medially to the midline, and terminates as the rectum at about the level of the third sacral vertebra -rectum: ~15 cm long; lies anterior to the sacrum and coccyx -anal canal: terminal 2-3 cm of the large intestine; mucous membrane is arranged in longitudinal folds called anal columns that contain a network or arteries and veins
parts of a neuron
-cell body: contains a nucleus surrounded by cytoplasm which includes organelles -dendrite: receiving or input portions -axon: long, thin, cylindrical projection; propagates nerve impulses toward another neuron -axon hillock: cone shaped elevation; joins axon to cell body -trigger zone: junction of axon hillock and initial segment; generates nerve impulses which travel along the axon to their destination -axon terminal: numerous fine processes originating from the axon -synaptic bulb: bulb-shaped swellings of the tips of axon terminals; contain synaptic vesicles that store neurotransmitters
cervical and lumbar enlargements
-cervical enlargement: extends from C4-T1; nerves to and from the upper limbs -lumbar enlargement: extends from T9-T12; nerves to and from the lower limbs
resting membrane potential
-charge of plasma membrane at rest; potential difference across membrane of resting cell -approximately -70mV in neurons (cytoplasmic side of membrane negatively charged relative to outside) -membrane termed polarized -generated by: differences in ionic makeup of ICF and ECF; differential permeability of the plasma membrane
chemical digestion vs mechanical digestion
-chemical digestion: large carbohydrate, lipid, protein, and nucleic acid molecules in food are split into smaller molecules by hydrolysis; digestive enzymes produced by salivary glands, tongue, stomach, pancreas, and small intestine catalyze these catabolic reactions -mechanical digestion: teeth cut and grind food before it is swallowed, and then smooth muscles of the small intestine churn the food to further assist the process; food molecules dissolve and mix with digestive enzymes
explain the structural changes that occur along the bronchial tree
-ciliated pseudostratified columnar epithelium (mucous membrane in the primary, secondary, and tertiary bronchi) > ciliated simple columnar epithelium with some Goblet cells (larger bronchioles) > ciliated simple cuboidal epithelium with no Goblet cells (smaller bronchioles) > nonciliated simple cuboidal epithelium (terminal bronchioles) -plates of cartilage gradually replace the incomplete rings of cartilage in primary bronchi and finally disappear in the distal bronchioles -as amount of cartilage decreases, the amount of smooth muscle increases. smooth muscle encircles the lumen in spiral bands and helps maintain patency. however, because there is not supporting cartilage, muscle spasms can close off the airway (ex. asthma)
describe features of the small intestine that increases the surface area of the small intestine for absorption
-circular folds: folds of the mucosa and submucosa; enhance absorption by increasing surface area and causing the chyme to spiral rather than move in a straight line as it passes through the small intestine -villi: fingerlike projections of the mucosa; increases surface area of epithelium available for absorption and digestion and gives the intestinal mucosa a velvety appearance; each villus is covered by epithelium and has a core of lamina propria that contains an arteriole, a venue, a blood capillary network, and a lacteal; nutrients absorbed by the epithelial covering of the villus enter the lacteal or capillary to enter the lymph or blood -microvilli: projections of the apical membrane of the absorptive cells; form the brush border; greatly increase surface area of the plasma membrane so larger amounts of digested nutrients can diffuse into absorptive cells in a given period; also contain several brush border enzymes that have digestive functions
Leydig cells
-clusters of cells in the spaces between adjacent seminiferous tubules -secrete testosterone
acinar cells
-clusters of exocrine cells of the pancreas -produce digestive enzymes that flow into the GI tract through a network of ducts
thyroid cartilage
-component of larynx -Adam's apple -two fused plates of hyaline cartilage that form the anterior wall of the larynx and give it a triangular shape -present in both males and females, but more prominent in males due to influence of male sex hormones on its growth during puberty -thyrohyoid membrane: ligament connecting the thyroid cartilage to the hyoid bone
cricoid cartilage
-component of larynx -a ring of hyaline cartilage that forms the inferior wall of the larynx -attached to first ring of cartilage of the trachea by the cricotracheal ligament -landmark for tracheotomy
epiglottis
-component of larynx -large, leaf-shaped piece of elastic cartilage that is covered with epithelium -during swallowing, pharynx and larynx rise. elevation of the pharynx widens it to receive food or drink and elevation of larynx causes the epiglottis to move down and form a lid over the glottis, closing it off
describe the components that form the blood brain barrier and explain the function
-consists mainly of tight junctions that seal together the endothelial cells of brain blood capillaries and a thick basement membrane that surrounds capillaries -allows certain substances in blood to enter brain tissue and prevents passage to others -easily cross by diffusion: lipid soluble substances, steroid hormones, nicotine, alcohol, barbiturates, caffeine, and water molecules -cross by facilitated diffusion: water soluble substances such as glucose and ions -do not pass at all: proteins, antibiotic drugs
structure of the muscularis layer of the large intestine and haustra
-consists of an external layer of longitudinal smooth muscle and an internal layer of circular smooth muscle -teniae coli: thickening of longitudinal muscles, forming three conspicuous bands that run most of the length of the large intestine; separated by portions of the wall with less or no longitudinal muscle; contractions create haustra; single layer of circular smooth muscle lies between the teniae coli -haustra: tonic contractions of the teniae coli, gathering the colon into a series of pouches and give it a puckered appearance
organization of sensory and motor neurons of the submucosal and myenteric plexuses of the enteric nervous system
-consists of ~100 million neurons (motor, sensory, interneurons) that extend from the esophagus to the anus -neurons are arranged into two plexuses: myenteric and submucosal -myenteric plexus: located between the longitudinal and circular smooth muscle layers of the muscularis; motor neurons mostly control GI tract motility -submucosal plexus: found within the submucosa; motor neurons control secretions of the organs of GI tract -interneurons interconnect the neurons of the myenteric and submucosal plexuses -sensory neurons supply mucosal epithelium and contain receptors that detect stimuli in the lumen of the GI tract; two types: chemoreceptors (respond to certain chemicals present in food) and mechanoreceptors (activated when food distends wall of GI tract)
role of seminiferous tubules in sperm production
-contain 2 types of cells: spermatogenic cells (sperm-forming cells) and Sertoli cells (support spermatogenesis) -spermatogonia (stem cells) develop from primordial germ cells that arise from yolk sac and enter testes during the fifth week of development; primordial germ cells differentiate into spermatogonia which remain dormant during childhood and begin producing sperm at puberty -toward lumen of the seminiferous tubule are layers of progressively more mature cells: primary spermatocytes, secondary spermatocytes, spermatids, and sperm cells -after a sperm cell has formed, it is released into the lumen of the seminiferous tubule
compare continuous and saltatory conduction
-continuous conduction: step-by-step depolarization of each adjacent segment of the plasma membrane; occurs in unmyelinated axons and in muscle fibres -saltatory conduction: impulse jumps from one Ranvier's node to the next; occurs along myelinated axons due to the uneven distribution of voltage-gated channels
medulla oblongata (aka medulla)
-continuous with the superior part of the spinal cord and forms the inferior part of the brain stem; begins at the foramen magnum and extends to the inferior border of the pons -helps regulate breathing, heart, and blood vessel function, provides reflexes for vomiting, deglutition, sneezing, coughing, and hiccuping
explain how levels of hormones in the blood are regulated
-controlled through negative feedback, in which rising levels of a hormone inhibit it's further release -3 mechanisms: humoral stimuli, hormonal stimuli, and neural stimuli -humoral stimuli: refer to the control of hormonal release in response to changes in extracellular fluid levels or ion levels -hormonal stimuli: refer to the release of hormones in response to hormones released by other endocrine glands -neural stimuli: refer to the release of hormones in response to neural stimulation
describe the organization and function of the posterior column
-conveys localized sensations of fine touch, vibration, and proprioception from the skin and joints -nerve impulses for touch, pressure, vibration, and proprioception from the limbs, trunk, neck, and posterior head ascend to the cerebral cortex along the posterior column-medial lemniscus pathway -first order neurons in the PC-MLP extend from sensory receptors in the limbs, trunk, neck, and posterior head into the spinal cord and ascend to the medulla oblongata on the same side of the body -in the spinal cord, axons of the first order neurons synapse with the dendrites of second order neurons, located in the gracile nucleus or cuneate nucleus of the medulla -nerve impulses for touch, pressure, vibration, and proprioception from the upper limbs, upper trunk, neck, and posterior head propagate along axons in the cuneate fascicles and arrive at the cuneate nucleus -nerve impulses for touch, pressure, vibration, and proprioception from the lower limbs and lower trunk propagate along axons in the gracile fascicles and arrive at the gracile nucleus -axons of the second order neurons cross to the opposite side of the medulla and enter the medial lemniscus (thin ribbonlike projection tract that extends from the medulla to the ventral posterior nucleus of the thalamus) -in thalamus, the axon terminals of second order neurons synapse with third order neurons which project their axons to the primary somatosensory area of the cerebral cortex
describe the coronary circulation
-coronary arteries branch from the ascending aorta and encircle the heart -when heart is contracting, little blood flows in the coronary arteries because they are squeezed shut; when heart is relaxed, high pressure of blood in the aorta propels blood through the coronary arteries, into capillaries, and then into coronary veins -2 coronary arteries (left and right) which branch from the ascending aorta and supply oxygenated blood to the myocardium -coronary veins= deoxygenated blood from myocardium drains into coronary sinus, which is supplied by: great cardiac vein (drains areas of heart supplied by left coronary artery), middle cardiac vein (drains areas of heart supplied by posterior interventricular branch of right coronary artery), small cardiac vein (drains right atrium and right ventricle), and anterior cardiac veins (drain the right ventricle and open directly into the right atrium)
structure and function of satellite cells
-cover surface of nerve cell bodies -regulation of extracellular environment of PNS neurons
describe the protective structures of the brain
-cranium -cranial meninges: dura mater, arachnoid mater, pia mater -dura mater has two layers: periosteal layer and meningeal layer -3 extensions of the dura mater separates parts of brain: falx cerebri (separates two hemispheres of cerebrum), falx cerebelli (separates two hemispheres of cerebellum), and tentorium cerebelli (separates the cerebrum from the cerebellum)
discuss how an action potential is propagated
-depends on positive feedback loop -travel from where they arise at the trigger zone to the axon terminals -action potential keeps its strength as it spreads along the membrane (propagation) -sodium flows in, voltage gated ion channels open -action potential travels along membrane, regenerating over and over at adjacent regions of membrane from the trigger zone to the axon terminals -can only propagate in this direction because the regions it has already passed are in their absolute refractory period
determinants of blood pressure
-depends on total volume of blood in the cardiovascular system -decrease in volume = decrease in amount circulating through the arteries
types of stimuli detected by mechanoreceptors
-detect mechanical stimuli -provide sensations of touch, pressure, vibration, proprioception, and hearing and equilibrium -monitor stretching of blood vessels and internal organs
diencephalon
-diencephalon: forms a central core of brain tissue just superior to the midbrain -thalamus: consists of paired local masses of gray matter organized into nuclei with interspersed tracts of white matter; relays almost all sensory input to cerebral cortex, contributes to motor functions by transmitting information from cerebellum and basal nuclei to primary motor areas of cerebral cortex, plays role in maintenance of consciousness -hypothalamus: small part of diencephalon located inferior to thalamus; controls and integrates activities of autonomic nervous system, produces hormones (releasing hormones, liberating hormones, oxytocin, antidiuretic hormone), regulates emotional and behavioural patterns, contains feeding and satiety centres, thirst centre, and suprachiasmatic nucleus, controls body temperature by serving as body thermostat
pulse pressure
-difference between systolic and diastolic pressure -normally ~40mmHg -provides information about condition of cardiovascular system; ie. conditions such as atherosclerosis, patent ductus arteriosus -SBP: DBP: PP = 3:2:1
describe the location of the stomach and identify structures
-directly inferior to the diaphragm in the abdomen -cardia: surrounds opening of the esophagus into the stomach -fundus: rounded portion superior to and to the left of the cardia -body: large central portion inferior to the fundus -pyloric antrum: connects to the body of the stomach -pyloric canal: connects to the pylorus -pylorus: connects to duodenum -rugae: large folds of mucosa when stomach is empty -greater curvature: convex lateral border -lesser curvature: concave medial border
describe the micturition
-discharge of urine from the urinary bladder -occurs via a combination of voluntary and involuntary muscle contractions -when volume of urine in bladder exceeds 200-400mL, pressure within the bladder increases considerably and stretch receptors in the wall transmit nerve impulses into spinal cord. these impulses propagate to micturition center in sacral spinal cord segments S2 and S3 and trigger a spinal reflex called the micturition reflex -micturition reflex: parasympathetic impulses from micturition centre propagate to urinary bladder wall and internal urethral sphincter. nerve impulses cause contraction of the detrusor muscle and relaxation of the internal urethral sphincter. on contraction of the urinary bladder wall and relaxation of the sphincters, urination takes place. urinary bladder filling causes a sensation of fullness that initiates a conscious desire to urinate before the micturition reflex actually occurs -although this is a reflex, in early childhood we learn to initiate it and stop it voluntarily; through learned control of external urethral sphincter muscle and certain muscles of pelvic floor, cerebral cortex can initiate micturition or delay its occurrence for a limited period
nasal septum
-divides nasal cavity into right and left sides -anterior portion consists of hyaline cartilage; the remainder is formed by the vomer and the perpendicular plate of the ethmoid, maxillae, and palatine bones
alveolar ducts
-division of respiratory bronchiole -simple squamous epithelium
respiratory bronchioles
-division of terminal bronchiole -have alveoli at ends
identify the regions of the small intestine
-duodenum: first part of small intestine; shortest region; retroperitoneal; starts at pyloric sphincter of the stomach and is in the form of a C shaped tube that extends about 25cm until it merges with the jejunum -jejunum: 1m long; extends to ileum -ileum: 2m long; joins the large intestine at a smooth muscle sphincter called the ileocecal sphincter
describe the spinal meninges
-dura mater: most superficial of the three meninges; thick strong layer composed of dense irregular connective tissue; meningeal dura mater of brain to S2 vertebra -arachnoid mater: middle layer of meninges; thin, avascular covering comprised of cells and thin, loosely arranged collagen and elastic fibres -pia mater: innermost layer of the meninges; thin transparent connective tissue layer that adheres to the surface of the spinal cord and brain; thin squamous to cuboidal cells with interlacing bundles of collagen fibres and some fine elastic fibres; contain many blood vessels that supply oxygen and nutrients to spinal cord -subarachnoid space: space between arachnoid mater and pia mater containing cerebrospinal fluid -epidural space: space between the dura mater and the wall of the vertebral canal
describe the fight-or-flight response of the sympathetic nervous system
-during physical or emotional stress, the sympathetic nervous system dominates the parasympathetic; sympathetic tone favours body functions that can support vigorous physical activity and rapid production of ATP -release of hormones by the adrenal medullae set in motion a series of responses: pupils dilate, HR increases, force of heart contraction increases, BP increases, airways dilate, blood vessels of GI tract and kidneys constrict, blood vessels that supply organs involved in exercise or fighting off danger dilate, liver cells perform glycogenolysis, adipose tissue cells perform lipolysis, release of glucose by the liver increases blood glucose level, and processes that are not essential for meeting the stressful situation are inhibited
describe the organization of preganglionic and postganglionic neurons
-each division of ANS has two motor neurons -first: preganglionic neuron: cell body is in brain or spinal cord; axon exits CNS as part of nerve and extends to autonomic ganglion -second: postganglionic neuron: lies outside the CNS in the PNS; forms synapse with autonomic ganglion -thus, preganglionic neurons convey nerve impulses from the CNS to autonomic ganglia, and postganglionic neurons relay the impulses from autonomic ganglia to visceral effectors
organization of blood and lymphatic vessels within the intestinal villi
-each villi contains a core of lamina propria containing: an arteriole, a venule, a blood capillary network, and a lacteal (lymphatic capillary) -nutrients absorbed by epithelial cells covering the villus pass through the wall of a capillary or a lacteal to enter blood or lymph
lung compliance
-effort required to stretch the lungs and chest wall -5 factors: 1) conditionals that decrease elasticity (scarring of the lungs due to elastin being replaced with inelastic cartilage ex. pulmonary fibrosis) 2) conditions that increase the water content of the lungs (filling of lung tissue with fluid makes the lungs stiff ex. pulmonary edema) 3) conditions that impair diaphragm flattening (ex. obesity, pregnancy); 4) conditions that cause lung collapse (ex. pneumothorax = air enters pleural cavity causing an increase in Pip) 5) conditions that increase alveolar surface tension (ex. surfactant deficiency)
describe the mechanism for electrolyte and water absorption by small intestine
-electrolytes enter absorptive cells via diffusion and secondary active transport; move out of cells via pumps (Na/K pump); most electrolytes are reclaimed rather than excreted by the body -water is absorbed via osmosis from the lumen of the intestines, through the absorptive cells, and into blood capillaries; depends on absorption of electrolytes and nutrients to maintain osmotic balance in blood
identify the connective tissue coverings of a spinal nerve
-epineurium: outermost covering wrapping the entire nerve; consists of fibroblasts and collagen fibres -perineurium: wraps fascicles; middle layer; thicker layer of connective tissue consisting of up to 15 layers of fibroblasts in a network of collagen fibres -endoneurium: wrap individual axons; innermost layer; consists of a mesh of collagen fibres, fibroblasts, and macrophages
structure of respiratory mucosa
-epithelium and lamina propria -pseudostratified ciliated epithelium with Goblet cells
two exceptions to neurotransmitter release in ANS
-exception 1: if the target is a sweat gland or arrector pili, the neurotransmitter at the effector will be acetylcholine (should be norepinephrine because it is part of SANS) -exception 2: if the chain is missing a post-synaptic fibre, the ganglia will release norepinephrine into the blood (found in adrenal gland medulla)
discuss how neurotransmitters excite or inhibit postsynaptic structures
-excitatory postsynaptic potential: a neurotransmitter that causes depolarization of the synaptic membrane, bringing it closer to the threshold -inhibitory postsynaptic potential: a neurotransmitter that causes hyperpolarization of the synaptic membrane, causing it to become more negative inside and even farther from the threshold
importance of elastic recoil during exhalation
-exhalation is passive process; no muscular contraction is involved so exhalation results from elastic recoil of chest wall and lungs -caused by: i) recoil of elastic fibres that were stretched during inhalation, ii) inward pull of surface tension due to the film of intrapleural fluid between the visceral and parietal plurae
midbrain
-extends from the pons to the diencephalon -conduct nerve impulses from motor areas in the cerebral cortex to the spinal cord, medulla, and pons -reflex centres for vision and hearing
vasa recta
-extensions of some efferent arterioles -long, loop-shaped capillaries that supply tubular portions of the nephron in the medulla
external and internal nares
-external nares: nostrils; lead into nasal vestibules -internal nares: two openings that allow communication between the nasal cavity and pharynx
describe the location of the somatic sensory receptors
-exteroreceptors: located at or near the external surface of the body; sensitive to stimuli originating outside the body and provide information about the external environment; ex. sensations of hearing, vision, smell, taste, touch, pressure, vibration -interoreceptors: located in blood vessels, visceral organs, muscles, and the nervous system and monitor conditions in the internal environment -proprioceptors: located in muscles, tendons, joints, and the inner ear; provide information about the body position, muscle length and tension, and the position and movement of your joints
describe the path of urine flow
-filtrate formed by nephrons drains into large papillary ducts (distal portion of collecting duct), which extend into the renal papillae of the pyramids -papillary ducts drain into a cuplike structure called a calyces. first, the papillary duct drains into a minor calyx, which then delivers filtrate to major calyx -once filtrate enters calyces, it becomes urine because no further reabsorption can occur due to the changes in epithelium from simple to transitional -from the major calyx, urine drains into a single large cavity called the renal pelvis, and then out through the ureter to the urinary bladder
neurotransmitter: acetylcholine
-first identified and best understood -released at neuromuscular junctions by some ANS neurons and some CNS neurons -synthesized from acetic and choline by enzyme choline acetylltransferase -degraded by enzyme acetylcholinesterase (AChE)
graded potential vs action potential
-graded potential: small deviation from the resting membrane potential that makes the membrane either more polarized or less polarized; occurs when a stimulus causes mechanically-gated or ligand-gated channels to open or close in an excitable cell's plasma membrane -action potential (aka impulse): a sequence of rapidly occurring events that decrease and reverse the membrane potential and then eventually restore it to the resting state; occurs in the axon of a neuron when depolarization reaches a certain level termed the threshold (-55mV)
describe the organization of first, second, and third-order neurons in somatic sensory pathways
-first order neurons: sensory neurons that conduct impulses from somatic sensory receptors into the brainstem or spinal cord; from the face, nasal cavity, oral cavity, teeth, and eyes, somatic sensory impulses propagate along the cranial nerves into the brainstem; from the neck, trunk, limbs, and posterior aspect of the head, somatic sensory impulses propagate along spinal nerves into the spinal cord -second order neurons: conduct impulses from the brainstem or spinal cord to the thalamus; axons decussate as they course through the brainstem or spinal cord before descending to the thalamus -third order neurons: conduct impulses from the thalamus to the primary somatosensory area on the same side; as impulses reach the primary somatosensory area, perception of the sensation occurs; because second order axons decussate as they pass through the brainstem or spinal cord, somatic sensory information on one side of the body is perceived by the primary somatosensory area on the opposite side of the brain
list the hormones released by follicular cells and parafollicular cells of the thyroid gland
-follicular cells: tetraiodothyronine (T4) and triiodothyronine (T3) -parafollicular cells: calcitonin
describe the organization and function of the corticobulbar tract
-formed by axons of UMNs from the cerebral cortex -descends along with the corticospinal tracts through the internal capsule of the cerebrum and cerebral peduncle of the midbrain -some axons decussate; others do not -axons terminate in motor nuclei of nerves III, IV, V, VI, VII, IX, X, XI, and XII; LMNs of cranial nerves convey impulses that control precise, voluntary movements of the eyes, tongue, and neck, plus chewing, facial expression, speech, and swallowing
locate and describe structure and function of left atrium
-forms most of the base of the heart -receives blood from lungs through 4 pulmonary veins -blood passes from LA to LV through bicuspid (mitral) valve
locate and describe structure and function of right atrium
-forms right surface of heart -receives blood from three veins: superior vena cava, inferior vena cava, and coronary sinus -blood passes from RA to RV through tricuspid valve (composed of dense connective tissue covered by endocardium)
surfactant
-found in alveolar fluid -complex mixture of phospholipids and lipoproteins -lowers the surface tension of alveolar fluid, which reduces the tendency of alveoli to collapse and thus maintains their patency
functions of respiratory system
-gas exchange -helps regulate body pH -produces sounds -participates in olfactory senses -excretes a little bit of heat and moisture
describe the reflex pathways of the enteric nervous system
-gastrointestinal reflex pathways -regulate GI secretion and motility in response to stimuli present in the lumen of the GI tract -initial components = sensory receptors (chemoreceptors and mechanoreceptors) associated with the sensory neurons of the ENS -axons of these sensory neurons can synapse with other neurons located in the ENS, CNS, or ANS informing these regions of the nature of the content and the degree of distension of the GI tract; these neurons subsequently activate or inhibit GI gland and smooth muscle, altering GI secretion and motility
histological features of the different segments of the renal tubule and collecting duct
-glomerular capsule: visceral layer consists of podocytes = modified simple squamous epithelial cells containing footlike projections that wrap around the single layer of endothelial cells of the glomerular capillaries and form the inner wall of the capsule; parietal layer consists of simple squamous epithelium and forms the outer wall of the capsule -renal tubule and collecting duct: PCT = simple cuboidal epithelial cells with a prominent brush border of microvilli on their apical surface; descending loop and first part of ascending loop = simple squamous epithelium; thick ascending loop = simple cuboidal to low columnar epithelium; in each nephron, final part of ascending limb makes contact with afferent arteriole, so columnar tubule cells are crowded together, known as macula densa; alongside macula densa, wall of afferent arteriole contains modified smooth muscle fibres called juxtaglomerular cells; distal part of DCT and collecting ducts = principal cells (have receptors for ADH and aldosterone) and intercalated cells (homeostasis of blood pH); collecting ducts drain into large papillary ducts = simple columnar epithelium
structure and function of renal corpuscle
-glomerulus: capillary network -glomerular capsule: double-walled epithelial cup that surround the glomerular capillaries; blood plasma is filtered and then filtered fluid is passed into renal tubules
neurotransmitter: amino acids
-glutamine -aspartate -glycine -GABA (gamma-aminobutyric acid) -released by CNS
structure of mature sperm
-head: contains nucleus with 23 highly condensed chromosomes; covering anterior 2/3s of the nucleus is the acrosome (cuplike vesicle filled with enzymes [hyaluronidase and proteases] that help sperm penetrate secondary oocyte) -tail: 4 parts = neck, middle piece, principal piece, and end piece; neck = constricted region just behind the head that contain centrioles (form microtubules); middle piece = contains mitochondria arranges in a spiral which provide ATP for locomotion of sperm to site of fertilization and for sperm metabolism; principal piece = longest portion of the tail
discuss the shock response assuming that the trigger is a severe injury and massive hemorrhage
-hemorrhage causes decrease in blood volume and blood pressure -kidneys secrete renin which converts angiotensin (plasma protein in liver) into angiotensin I -angiotensin-converting enzyme (ACE) in capillaries of lungs converts angiotensin I into the hormone angiotensin II -angiotensin II stimulates the adrenal cortex to secrete aldosterone -aldosterone increases reabsorption of Na+ in the kidneys, which in turns causes reabsorption of water. as a result, less water is lost in the urine. aldosterone also stimulates kidneys to secrete K+ and H+ into the urine -with increased water reabsorption by the kidneys, blood volume increases causing BP to return to normal -angiotensin II also stimulates contraction of smooth muscle in the walls of arterioles. the resulting vasoconstriction of the arterioles increases BP, raising it to normal
describe the blood supply to the liver
-hepatic artery carries oxygenated blood -hepatic portal vein contain deoxygenated blood containing newly absorbed nutrients, drugs and possibly microbes and toxins from the GI tract -branches from both blood vessels carry blood into hepatic sinusoids, where oxygen, most of the nutrients, and certain toxic substances are taken up by the hepatocytes -products manufactured by hepatocytes and nutrients needed by other cells are secreted back into the blood, which drains into a central vein and then into a hepatic vein
histological components of the liver
-hepatocytes: major functional cells of the liver; perform a wide array of metabolic, secretory, and endocrine functions; membrane has grooves which provide spaces for canaliculi into which the hepatocytes secrete bile -hepatic sinusoids: highly permeable blood capillaries between rows of hepatocytes that receive oxygenated blood from branches of the hepatic artery and nutrient rich deoxygenated blood from branches of the hepatic portal vein; converge and deliver blood into a central vein where it flows into the hepatic veins which drain into the inferior vena cava -portal triad: a bile duct, branch of the hepatic artery, and branch of the hepatic vein -bile canaliculi: small ducts between hepatocytes that collect bile produced by the hepatocytes; from canaliculi, bile passes into bile ductules and then into bile ducts which merge and form right and left hepatic ducts. these unite and exit the liver as the common hepatic duct which joins the cystic duct from the gallbladder to form the common bile duct which carries bile to the duodenum -hepatic macrophages (stellate reticuloendothelial cells): fixed phagocytes located in the hepatic sinusoids; destroy worn out white and red blood cells, bacteria, and other foreign matter in the venous blood draining from the GI tract
structure and function of urinary bladder
-hollow, distensible muscular organ situated in the pelvic cavity posterior to the pubic symphysis -folds of peritoneum hold urinary bladder in place -capacity of 700-800mL -trigone: small triangular area in the floor of the urinary bladder; contains two ureteral openings -3 layers: mucosa, muscularis, adventitia -mucosa: deepest layer; mucous membrane composed of transitional epithelium (permits stretching) and an underlying lamina propria -muscularis (detrusor muscle): intermediate layer; consists of inner longitudinal, middle circular, and outer longitudinal smooth muscle layers; circular fibres form internal urethral sphincter; skeletal muscle forms external urethral sphincter -adventitia: superficial layer; areolar connective tissue continuous with that of the ureters
blood pressure
-hydrostatic pressure exerted by blood on the walls of a blood vessel -highest in the aorta and large systemic arteries -systolic blood pressure: highest pressure attained in the arteries during systole -diastolic blood pressure: lowest arterial pressure during diastole
describe the relationship between the hypothalamus and pituitary gland
-hypothalamus thought of as "master" of pituitary gland -pituitary gland secretes seven different hormones; hypothalamus secretes nine different hormones -together, these hormones play important roles in regulation of virtually all aspects of growth, development, metabolism, and homeostasis
describe where the spinal cord begins and terminates
-in adults: medulla oblongata to the superior border of L2 -in newborns: medulla oblongata to L2/L3
laryngopharynx
-inferior portion of the pharynx -begins at level of the hyoid bone -opens into the esophagus posteriorly and the larynx anteriorly -both a respiratory and digestive pathway -lined by nonkeratinized stratified squamous epithelium
locate and describe structure and function of right ventricle
-inside contains a series of ridges formed by raised bundles of cardiac muscle fibres called trabeculae carneae -blood passes from the RV through the pulmonary valve into a large artery called the pulmonary trunk, which divides into right and left pulmonary arteries and carries blood to the lungs
cholinergic receptors
-integral membrane protein in the postsynaptic plasma membrane -2 types (both bind ACh): nicotinic and muscarinic -nicotinic receptors are present in both sympathetic and parasympathetic postganglionic neurons, chromaffin cells of the adrenal medullae, and in the motor end plate at the NMJ; nicotine binds to these receptors -muscarinic receptors are present in all effectors innervated by parasympathetic postganglionic axons -ACh activates both receptors -ACh activation causes depolarization and thus excitation of the postsynaptic cell in nicotinic receptors -ACh activation can cause depolarization (excitation) or hyper polarization (inhibition) in muscarinic receptors
ANS receptor
-integral membrane proteins located in the plasma membrane of the postsynaptic neuron or effector cell
oropharynx
-intermediate portion of pharynx -lies posterior to oral cavity and extends from soft palate inferiorly to the level of the hyoid bone -only opening is the fauces (opening from mouth) -has both respiratory and digestive functions; common passageway for food, air, and drink -lined with nonkeratinized stratified squamous epithelium because it is subject to abrasion by food -2 pairs of tonsils: palatine and lingual
intestinal juice vs gastric juice
-intestinal juice: neutralizes HCl coming from the stomach; releases gastrointestinal hormones into the bloodstream; contains digestive enzymes that facilitate the digestion and absorption of food -gastric juice: contain HCl; digest proteins, lipids, and carbohydrates; absorption of extrinsic factor which assists in haemopoesis; helps form chyme
explain how the larynx functions in sound production
-intrinsic laryngeal muscles attach to vocal folds; as they contract and relax, air passing through them produces sound -pitch is controlled by the tension on the vocal folds; when pulled taught, they vibrate more rapidly and a higher pitch results; decreasing muscular tension causes them to vibrate slower and produce lower pitched sounds -due to androgens, vocal folds are usually thicker and longer in males and vibrate slower, which is why males have deeper voices -pharynx, mouth, nasal cavity, and paranasal sinuses all act as resonating chambers -produce vowel sounds by constricting and relaxing muscles in wall of pharynx; muscles of face, lips, and tongue help us enunciate -whispering is accomplished by closing all but the posterior portion of the rima glottidis
pancreatic islets
-islets of Langerhans -tiny clusters of endocrine tissue scattered among acini
isovolumetric contraction vs isovolumetric relaxation
-isovolumetric: no change in volume -isovolumetric contraction: exact point when systole is about to start but no valves have opened -isovolumetric relaxation: when systole has finished and the heart hasn't relaxed enough to start sucking the blood in
location and structure of the juxtaglomerular apparatus
-juxtaglomerular cells and macula densa -helps regulate blood pressure within the kidneys
life cycle of erythrocyte
-kidney senses lack of RBCs and/or low O2 in blood = releases EPO -EPO goes to bone marrow = myeloid stem cell differentiates into RBC -RBC ejects nucleus and organelles, becoming biconcave -RBC lasts 120 days since it has no organelles for repair -goes through the liver/spleen and gets filtered; if it doesn't go through, macrophages come and eat it -RBCs are broken down into globin and heme; globin is recycled to liver; heme gets excreted in bile
structures of the urinary system
-kidneys: paired, reddish, kidney bean-shaped organs located just above the waist between the peritoneum and the posterior wall of the abdomen; retroperitoneal -ureters: duct through which urine passes from the kidneys to the bladder -urinary bladder: muscular sac which functions in storage of urine -urethra: tube which carries urine from the bladder out of the body
identify the intervertebral foramen
-large hole in vertebra -allows for the passage of the spinal cord -protects spinal cord
purkinje fibres
-large-diameter fibres -carry action potential from left and right branches to the myocardium of the ventricles
describe the organization and function of the corticospinal tract
-lateral corticospinal tract = corticospinal axons that decussate in the medulla form this tract in the lateral white column of the spinal cord; control movements of the distal parts of the limbs -anterior corticospinal tract = corticospinal axons that do not decussate in the medulla form this tract in the anterior white column of the spinal cord; control movements in the trunk and proximal parts of the limbs
parietal lobe
-lateral parts of brain -functions in processing of sensory information, interpreting visual information, and processing language and mathematics
discuss the role of ion channels in establishing the resting membrane potential
-leak channels: gated channels that randomly open and close; found in nearly all cells -ligand-gated channels: gated channels that open in response to binding of ligand (chemical) stimulus; found in dendrites of some sensory neurons and dendrites and cell bodies of interneurons and motor neurons -mechanically-gated channels: gated channels that open in response to mechanical stimulus (i.e., touch, pressure, vibration, or tissue stretching); found in dendrites of some sensory neurons -voltage-gated channels: gated channels that open in response to voltage stimulus (change in membrane potential); found in axons of all types of neurons
structure and function of the glomerular filtration membrane
-leaky barrier composed of glomerular capillaries and podocytes -permits filtration of water and small solutes but prevents filtration of most plasma proteins and blood cells -consists of 1) fenestrations of glomerular endothelial cells: prevents filtration of blood cells but allows all components of blood plasma to pass through, 2) basement membrane: prevents filtration of larger proteins, 3) slit membrane between pedicels: prevents filtration of medium sized proteins
pons
-lies directly inferior to the medulla and anterior to the cerebellum -bridge that connects parts of the brain with one another by bundles of axons -autonomic respiratory control centre
describe the anatomical location of the heart
-lies in mediastinum (anatomical region that extends form sternum to the vertebral column, from first rib to diaphragm, and between the lungs) -about 2/3 of the heart lies to the left of the midline -apex rests on the diaphragm; base is opposite the apex
location and structure of the esophagus
-lies posterior to the trachea -pierces diaphragm through an opening called the esophageal hiatus -collapsible muscular tube; ~25 cm long
chemical digestion of lipids in the small intestine
-lipases: molecules that splits triglycerides and phospholipids -most lipid digestion occurs in small intestine through pancreatic lipase -triglycerides are broken down by pancreatic lipase into fatty acids and monoglycerides; liberated fatty acids can be either short-chain fatty acids or long-chain fatty acids -emulsification: process in which a large lipid globule is broken down into several small lipid globules, providing a large surface area that allows pancreatic lipase to function more effectively
describe the differences between lipid-soluble and water-soluble hormones in terms of blood transport
-lipid-soluble: most are bound to transport proteins in the blood -water-soluble: flow freely in the plasma
location and anatomy of liver and gallbladder
-liver: inferior to the diaphragm; occupies most of the right hypochondriac and part of the epigastric region of the abdominal cavity; right and left lobes, quadrate lobe, caudate lobe -gallbladder: pear-shaped sac located in a depression of the posterior surface of the liver; 7-10cm long; fundus, body, and neck
identify lung structures
-lobes: sections of the lungs; right = 3 lobes, left = 2 lobes -apex: narrow superior portion of the lung -base: broad inferior portion of the lung; concave shape and fits over the convex area of the diaphragm -costal surface: surface of lung lying against the ribs; matches rounded curvature of ribs -mediastinal surface: contains a region called the hilium through which bronchi, pulmonary blood vessels, lymphatic vessels, and nerves enter and exit -cardiac notch: concavity in left lung in which the apex of the heart lies
describe the process of mechanical digestion through segmentation contractions in the small intestines
-localized, mixing contractions -occur in portions of the intestine distended by a large volume of chyme -mixes chyme with digestive juices and bring the particles of food into contact with the mucosa for absorption; they do not push intestinal contents along the tract -segmentation starts with contractions of circular muscle fibres in a portion of the small intestine, causing the small intestine to constrict into segments. next, muscle fibres that encircle the middle of each segment also contract, dividing each segment again. finally, the fibres that first contracted relax, and each small segment unites with an adjoining small segment so that large segments are formed again. as this sequence of events repeats, the chyme sloshes back and forth. -occur most rapidly in the duodenum, about 12 times per minute, and progressively slow to about 8 times per minute in the ileum
location, structure, and function of trachea
-located anterior to esophagus; extends from the larynx to the superior border of T5 where it divides into right and left primary bronchi -4 layers = mucosa, submucosa, hyaline cartilage, and adventitia; mucosa consists of ciliated pseudostratified columnar epithelium and an underlying layer of lamina propria; submucosa consists of areolar connective tissue that contains seromucous glands and their ducts; 16-20 C-shaped horizontal rings of hyaline cartilage connected by dense connective tissue; opening of C-shaped rings contains trachealis muscle (smooth muscle fibres) allowing the diameter of trachea to change slightly -protection against dust; inhalation and exhalation; C-shaped rings provide support so airway doesn't collapse; adventitia joins trachea to surrounding tissues
function of uterus
-located between urinary bladder and rectum -pathway for sperm deposited in the vagina to reach the uterine tubes -site of implantation of a fertilized ovum, development of the fetus during pregnancy, and labor -source of menstrual flow during cycles when implantation did not occur
precentral gyrus
-located immediately anterior to the central sulcus -primary motor area of the cerebral cortex
postcentral gyrus
-located immediately posterior to the central sulcus -primary somatosensory area of the cerebral cortex
structure of ovarian follicle
-located in cortex -consist of oocytes in various stages of development plus the cells surrounding them; surrounding cells nourish developing oocyte and begin to secrete estrogens as the follicle grows larger -follicular cells: cells surrounding oocytes form a single layer -granulosa cells: later in development, cells surrounding oocytes form several layers
describe the location, hormones released and functions of the testes
-location: oval glands that lie in the scrotum -hormones released: testosterone, inhibin testosterone = stimulates descent of testes before birth; regulates sperm production; promotes development and maintenance of male secondary sex characteristics inhibin = inhibits secretions of FSH from anterior pituitary
describe the location, hormones released and functions of the ovaries
-location: paired oval bodies located in the female pelvic cavity -hormones released: estrogens and progesterone, relaxin, inhibin estrogens and progesterone = regulate female reproductive cycle, maintain pregnancy, prepare mammary glands for lactation, and promote development and maintenance of female secondary sex characteristics relaxin = increases flexibility of pubic symphysis during pregnancy; helps dilate uterine cervix during labour and delivery inhibin = inhibits secretion of FSH from anterior pituitary
describe the organization of upper and lower motor neurons in somatic motor pathways
-lower motor neurons (LMNs): motor neurons that extend out of the brainstem and spinal cord to innervate skeletal muscles in the body; all excitatory and inhibitory signals that control movement converge on LMNs; have their cell bodies in the lower parts of the CNS (brain and spinal cord) -upper motor neurons (UPMs): send input to local circuit neurons and LMNs; have cell bodies in motor processing centres in the upper parts of the CNS
functional significance of mucus produced by goblet cells of large intestine
-lubricates the passage of colonic contents -protects the intestinal wall from irritating acids and gasses released by bacteria in the colon
functions of LH and FSH
-luteinizing hormone: stimulates interstitial cells in-between the seminiferous tubules to secrete testosterone -follicle stimulating hormone: acts indirectly to stimulate spermatogenesis
structure of gallbladder wall and functional significance of the rugae and muscle layer
-mucosa consists of simple columnar epithelium arranged in rugae -wall lacks submucosa -middle, muscular coat of wall consists of smooth muscle that contracts to eject the contents of the gallbladder into the cystic duct -rugae allow the volume to change
describe secretions released by intestinal glands and enteroendocrine cells of the small intestine
-lysozyme: bactericidal enzyme; capable of phagocytosis; regulates microbial population in small intestine -secretin: inhibits secretion of gastric acid by parietal cells of stomach; stimulates production of bicarbonate from the ductal cells of the pancreas; regulates pH of duodenum -cholecystokinin: stimulated by HCl; stimulates the gallbladder to release bile into the small intestine -glucose-dependent insulinotropic peptide: stimulates release of insulin
describe how cerebrospinal fluid is synthesized
-majority of production is from the choroid plexus (network of blood capillaries in the walls of the ventricles; ependymal cells joined by tight junctions cover the capillaries of the choroid plexuses) -selected substances (mostly water) from the blood plasma are filtered from the capillaries and secreted by the ependymal cells to produce the cerebrospinal fluid
describe the digestive processes that occur in the mouth (mechanical and chemical)
-mechanical digestion: mastication = food is manipulated by tongue, ground by teeth, and mixed with saliva forming a bolus -chemical digestion: salivary amylase are secreted by salivary glands and initiate the breakdown of starch from disaccharides into monosaccharides; lingual lipase is secreted by the lingual glands and is activated in the acidic environment of the stomach, starting to work after food is swallowed to break down triglycerides into diglycerides
digestive processes that occur in the stomach (mechanical and chemical)
-mechanical: peristalsis causes propulsion (gastric contents move from body into antrum) and retropulsion (contents are forced back into body) -chemical: salivary amylase continues to digest; churning action mixes chyme with acidic gastric juice, inactivating salivary amylase and activating lingual lipase which starts to digest triglycerides; pepsin breaks down proteins; gastric lipase breaks down lipids
how central chemoreceptors monitor and regulate breathing
-medulla regulates breathing -chemoreceptors are part of PNS and are sensitive to changes in PO2, H+, and PCO2 in blood -axons of sensory neurons in aortic body are part of vagus (X) nerve; axons of sensory neurons in carotid body are part of glossopharyngeal (IX) nerve -because CO2 is lipid soluble, it diffuses across the blood brain barrier into the CSF where it combines with water to form carbonic acid (H2CO3). carbonic acid quickly breaks down into H+ and HCO3-. an increase in H+ and an increase in CO2 indicates that breathing is too slow, and the medulla produces a response to breathe faster. a decrease in H+ and a decrease in CO2 indicates fast breathing and stimulates the medulla to slow down the breathing
regulation of breathing
-medullary rhythmicity area: controls the basic rhythm of breathing; receives input from the pons, higher brain centres, and sensory neurons; contains motor neurons that control respiratory muscles (dorsal respiratory group [motor neurons for muscle control of quiet breathing] and ventral respiratory group [determines rhythm of breathing]) -respiratory centre in the pons modifies the rate and depth of breathing set and receives input from sensory neurons (chemoreceptors, baroreceptors, lung stretch volume receptors, airway irritant receptors, proprioceptors) and higher brain centres (limbic system, hypothalamus, cerebral cortex)
locate and describe structure and function of pericardium
-membrane surrounding and protecting the heart -confines heart to its position while allowing sufficient freedom of movement for vigorous and rapid contraction -consists of 2 main parts: 1) fibrous pericardium: tough, inelastic, dense irregular connective tissue that prevents overstretching of the heart, provides protection, and anchors the heart in the mediastinum, and 2) serous pericardium: thinner, more delicate membrane that forms a double layer around the heart with a serous fluid in between that lubricates and prevents friction of the heart as it contracts
stages of oogenesis
-mitosis: occurs during early fetal life; oogonium differentiates into primary oocyte -meiosis I: begins during fetal development; after puberty, primary oocytes complete meiosis I, producing secondary oocyte and a first polar body (smaller cell of discarded nuclear material) that may or may not divide again -meiosis II: secondary oocyte begins meiosis II; secondary oocyte and first polar body is ovulated; after fertilization, meiosis II resumes; oocyte splits into an ovum and a second polar body -nuclei of sperm cell and ovum unite forming a diploid (2n) zygote
functions of stomach
-mixes saliva, food, and gastric juice to form chyme -serves as reservoir for food before release into small intestine -secretes gastric juice which contains HCl (kills bacteria and denatures proteins), pepsin (begins the digestion of proteins), intrinsic factor (aids absorption of vitamin B12), and gastric lipase (aids digestion of triglycerides) -secretes gastrin into blood
general transport mechanisms used for absorption of monosaccharides, amino acids and peptides, and lipids and bile salts by intestinal epithelial cells
-monosaccharides: facilitated diffusion (ie. fructose) or active transport (ie. glucose and galactose) -amino acids and peptides: active transport -lipids and bile salts: simple diffusion
describe the route of transport of absorbed nutrients from the small intestine
-most absorbed nutrients and water diffuse into capillary blood; carried to liver first via hepatic portal vein -large hydrophobic nutrients leave intestinal epithelial cells by exocytosis and enter lacteals in the villus, eventually draining into the subclavian veins
characteristics and function of astrocytes
-most abundant, versatile, and highly branched glial cells -cling to neurons, synaptic endings, and capillaries -functions: support and brace neurons; play role in exchanges between capillaries and neurons through BBB; guide migration of young neurons; respond to nerve impulses and neurotransmitters; influence neuronal functioning
diaphragm
-most important muscle in inhalation -dome-shaped skeletal muscle that forms floor of thoracic cavity -innervated by fibres of the phrenic nerves, which emerge from spinal cord at C3, C4, and C5
describe the process in which contents are moved through the large intestine
-movements begin when substances pass the ileocecal sphincter, filling the cecum and accumulating in the ascending colon -haustral churning: haustra remain relaxed and become distended when they fill up. when the distension reaches a certain point, the walls contract and squeeze the contents into the next haustrum -mass peristalsis: final movement where a strong peristaltic wave that begins at about the middle of the transverse colon quickly drives the contents of the colon into the rectum
function of MALT in lamina propria of small intestine
-mucosa-associated lymphoid tissue -initiate immune responses to ingested and inhaled antigens; prevent bacteria from entering bloodstream -contain both T and B lymphocytes -solitary lymphatic nodules are most numerous in distal part of the ileum -Peyer's patches are also present in ileum
structural classification of neurons
-multipolar: have several dendrites and one axon; brain and spinal cord -bipolar: one main dendrite and one axon; retina of eye, inner ear, olfactory area of brain -unipolar: have dendrites and one axon that are fused together to form a continuous process that emerges from the cell body; function as sensory receptors
histological features of the stomach wall that differ from other areas of the GI tract
-muscularis has three layers of smooth muscle rather than the two layers in the esophagus and small and large intestine -mucosa is thicker due to depth of gastric pits -gastric pits lead to gastric gland that secrete gastric juice
compare control of body functions by the nervous system and endocrine system
-nervous system: acts through nerve impulses conducted along axons of neurons; at synapses, nerve impulses trigger the release of neurotransmitters -endocrine system: controls body activities by releasing hormones
define nerve plexus
-networks of axons on both the left and right sides of the vertebral body -nerves branch off from this
neurotransmitter: gasotransmitters
-nitric oxide (NO), carbon monoxide (CO) -bind with G protein-coupled receptors in the brain -lipid soluble -synthesized on demand -NO involved in learning and formation of new memories, brain damage in stroke patients, smooth muscle relaxation in intestine
compare quiet and forceful breathing
-normal quiet breathing: inhalation = diaphragm and external intercostals contract; exhalation = diaphragm and external intercostals relax -forceful breathing: inhalation = sternocleidomastoid, scalene, and pectoralis minor also contract; exhalation = abdominal and internal intercostal muscles contract
obligatory water reabsorption vs facultative water reabsorption
-obligatory: water movement that cannot be prevented; usually recovers 85% of filtrate produced -facultative: allows precise control of water reabsorption; occurs in DCT and collecting system
cerebellum
-occupies the inferior and posterior aspects of the cranial cavity -highly folded surface that increases the surface area of its outer gray matter cortex, allowing for a greater number of neurons -regulates muscle movement and posture; plays a role in motor learning
locate the primary somatosensory area in the cerebral cortex and explain its function in somatic sensation
-occupies the postcentral gyrus of the parietal lobes -each region in this area receives sensory input from a different part of the body -relative sizes of these regions are proportional to the number of specialized sensory receptors within the corresponding part of the body
locate the primary motor area and explain its function in movement
-occupies the precentral gyrus of the frontal lobe -electrical stimulation of any point in the primary motor area causes contraction of specific muscles on the opposite side of the body -controls muscles by forming descending pathways that extend to the spinal cord and brainstem
describe peristalsis
-occurs during the esophageal stage of swallowing -progression of coordinated contractions and relaxations of the circular and longitudinal layers of the muscularis -moves bolus onward
cranial nerves (12)
-olfactory (I) nerve: sensory nerve; conducts nerve impulses for olfaction -optic (II) nerve: sensory nerve; conducts nerve impulses for vision -oculomotor (III) nerve: motor nerve; controls movements of the eyeball and upper eyelid -trochlear (IV) nerve: motor nerve; controls movement of the eyeball -trigeminal (V) nerve: mixed nerve; sensory = carry nerve impulses for touch, pain, and thermal sensations; motor = mastication -abducens (VI) nerve: motor nerve; controls abduction of the eyeball -facial (VII) nerve: mixed nerve; sensory = relay touch, pain, and thermal sensations; motor = contraction of facial muscles -vestibulocochlear (VIII) nerve: sensory nerve; carries impulses for equilibrium and hearing -glossopharyngeal (IX) nerve: mixed nerve; sensory = taste, monitor BP in carotid sinus, conveys touch, pain, and thermal sensations; motor = assist in swallowing and secretes saliva -vagus (X) nerve: mixed nerve; sensory = touch, pain, and thermal sensations of the external ear, conveys hunger, fullness, and discomfort, baroreceptors and chemoreceptors in carotid sinus; motor = swallowing, vocalization, and coughing -accessory (XI) nerve: motor nerve; coordinates head movements -hypoglossal (XII) nerve: motor nerve; speech and swallowing
define neurotransmitter
-one of a variety of molecules within axon terminals that are released into the synaptic cleft in response to a nerve impulse that changes the membrane potential of the postsynaptic neuron -based on the neurotransmitter they produce and release, autonomic neurons are classified as either cholinergic or adrenergic
oogonia vs primary oocytes vs secondary oocytes
-oogonia: developed from primordial germ cells during early fetal development; diploid (2n) -primary oocyte: develop from oogonia at birth -secondary oocyte: at puberty, FSH and LH cause development of secondary oocytes from primary oocytes
vascular resistance
-opposition of blood flow due to friction between blood and the walls of blood vessels -influenced by: 1) size of lumen = smaller the lumen, the greater its resistance to blood flow 2) blood viscosity = higher the viscosity, the higher its resistance 3) total blood vessel length = the longer the blood vessel, the greater the resistance
identity and describe the structure of the oral cavity
-oral cavity: formed by cheeks, hard and soft palates, and tongue -palate: wall or septum that separates the oral cavity from the nasal cavity, and forms the roof of the mouth; hard palate = anterior portion of the roof of the mouth formed by maxillae and palatine bones and covered by a mucus membrane; soft palate = forms posterior portion of roof of mouth and is an arch-shaped muscular partition between the oropharynx and nasopharynx that is lined with mucus membrane -salivary glands: parotid glands (inferior and anterior to ears), submandibular glands (found in floor of mouth), and sublingual glands (beneath tongue, superior to submandibular glands)
describe the composition of the outer cortex and inner medulla of the ovaries
-outer cortex: deep to tunica albuginea; consists of ovarian follicles surrounded by dense irregular connective tissue containing collagen fibres and fibroblast like cells called stromal cells -inner medulla: deep to ovarian cortex; consists of more loosely arranged connective tissue and contains blood vessels, lymphatic vessels, and nerves
describe the location of the adrenal glands
-paired -one lies superior to each kidney in the retroperitoneal space -flattened pyramid shape
ovaries
-paired glands -produce gametes, secondary oocytes that develop into mature ova after fertilization -produce hormones including progesterone and estrogen, inhibin, and relaxin
locate the testes and describe its organization into lobules
-paired oval glands in the scrotum -septa divide testes into 200-300 lobules -each lobule contains 1-3 tightly coiled tubules (seminiferous tubules) where sperm are produced
organization of endocrine and exocrine cells in the pancreas
-pancreas is made up of small clusters of glandular epithelial cells -endocrine: pancreatic islets; ~1%; secrete glucagon, insulin, somatostatin, and pancreatic polypeptide -exocrine: acini; ~99%; secrete a mixture of fluid and digestive enzymes (pancreatic juice)
target, regulation, and function of glucagon
-pancreatic hormone -target: liver -regulation: decreased blood level of glucose, exercise, and mainly protein meals stimulate secretion; somatostatin and insulin inhibit secretion -function: raises blood glucose level by accelerating breakdown of glycogen into glucose in liver (glycogenolysis), converting other nutrients into glucose in liver (gluconeogenesis), and releasing glucose into blood
target, regulation, and function of insulin
-pancreatic hormone -target: liver and almost all other organs -regulation: increased blood level of glucose, acetylcholine, arginine, and leucine, glucagon, GIP, GH, and ACTH stimulate secretion; somatostatin inhibits secretion -function: lowers blood glucose level by accelerating transport of glucose into cells, converting glucose into glycogen (glycogenesis), and decreasing glycogenolysis and gluconeogenesis; increases lipogenesis and stimulates protein synthesis
anatomy of the duct system connecting the pancreas to the duodenum
-pancreatic juices are secreted by exocrine cells into small ducts that unite to form two larger ducts, which in turn convey the secretions into the small intestine -pancreatic duct: larger of the two ducts; joins common bile duct from the liver and gallbladder and enters the duodenum as a dilated common duct called the hepatopancreatic ampulla -hepatopancreatic ampulla: opens on an elevation of the duodenal mucosa known as the major duodenal papilla -hepatopancreatic sphincter: mass of smooth muscle surrounding the ampulla that regulates the passage of pancreatic juice and bile through the hepatopancreatic ampulla into the duodenum -accessory duct: leads from the pancreas and empties into the duodenum
describe the cell types that form the intestinal glands
-paneth cells: secrete lysozyme; regulate microbial population in small intestine -S cells: secrete secretin -CCK cells: secrete cholecystokinin -K cells: secrete glucose-dependent insulinotropic peptide (GIP) -S cells, CCK cells, and K cells are all enteroendocrine cells
structure and function of pleural membranes
-parietal pleura: superficial layer; lines wall of thoracic cavity -visceral pleura: deep layer; covers lungs themselves -pleural cavity: small space between the plurae containing a small amount of lubricating fluid secreted by the membranes; prevents friction and causes the two membranes to adhere to each other
cardiac accelerator nerves
-part of the sympathetic nervous system -stimulate the SA node to increase heart rate
explain the process of pepsinogen activation in the stomach
-passage of food into stomach stimulates chief cells -chief cells produce pepsinogen -converted into pepsin when it comes into contact with HCl secreted by parietal cells or active pepsin molecules
functions of kidneys
-regulate blood volume and composition; help regulate blood pressure, pH, and glucose levels; produce two hormones (calcitriol and erythropoietin); excrete wastes in urine -ureters transport urine from kidneys to urinary bladder -urinary bladder stores urine and expels it into urethra -urethra discharges urine from the body
relate the structure of the pharynx to its functions
-relaxed skeletal muscle help keep the pharynx patent -contraction of skeletal muscle assists in deglutition
cholinergic neurons
-release the neurotransmitter acetylcholine -in ANS, includes: 1) all sympathetic and parasympathetic preganglionic neurons, 2) sympathetic postganglionic neurons that innervate most sweat glands, and 3) all parasympathetic postganglionic neurons
describe the peritoneum, omentum, and mesentary
-peritoneum = largest serous membrane of the body; consists of a layer of simple squamous epithelium (mesothelium) with an underlying supporting layer of areolar connective tissue; divided into parietal peritoneum (lines wall of abdominal cavity) and visceral peritoneum (covers organs in the cavity and is their serosa); slim space containing lubricating fluid is called peritoneal cavity; contains 5 large folds that bind the organs to one another and to the wall of the cavity -greater omentum = largest peritoneal fold; drapes over the transverse colon and coils of the small intestine; double sheet that folds back on itself giving it a total of four layers; contains adipose tissue which expands with weight gain (beer belly); lymph nodes contribute macrophages and antibody-producing plasma cells that help combat and contain infections of the GI tract -falciform ligament = attaches liver to the anterior abdominal wall -lesser omentum = anterior fold in the serosa of the stomach and duodenum and it connects the stomach and duodenum to the liver; pathway for blood vessels entering the liver and contains the hepatic portal vein, common hepatic artery, and common bile duct along with some lymph nodes -mesentery = fan-shaped fold of the peritoneum; binds jejunum and ileum of the small intestine to the posterior abdominal wall; most massive peritoneal fold and is typically laden with fat; double layer with blood, lymphatic vessels and lymph nodes in between -mesocolon = two separate folds of the peritoneum that bind the transverse colon and sigmoid colon of the large intestine to the posterior abdominal wall; carries blood and lymphatic vessels to the intestines; together with the mesentery, it holds intestines loosely in place allowing movement as muscular contractions mix and move the luminal contents along the GI tract
tonsils
-pharyngeal tonsils/adenoid (nasopharynx) -palatine and lingual tonsils (oropharynx)
describe the motor homunculus and identify the body regions with the largest representation in the primary motor area
-physical representation of the primary motor area -largest representation: muscles in the thumb, fingers, lips, tongue, and vocal cords
describe the sensory homunculus and identify the body regions with the largest representation in the primary somatosensory area
-physical representation of the primary somatosensory area -largest representation: lips, face, tongue, and hands
granulosa cells
-possess FSH receptors only -make estrogen and secrete inhibin
identify the posterior, lateral, and anterior gray horns
-posterior horns: contain axons of incoming sensory neurons as well as cell bodies and axons of interneurons -anterior horns: contain somatic motor nuclei (clusters of cell bodies of somatic motor neurons) that provide nerve impulses for contraction of skeletal muscles -lateral horns: present only in thoracic and upper lumbar segments of the spinal cord; contain autonomic motor nuclei (clusters of cell bodies of autonomic motor neurons) that regulate the activity of cardiac muscle, smooth muscle, and glands
occipital lobe
-posterior part of brain -functions in visual processing
target, regulation, and function of oxytocin
-posterior pituitary -target: uterus and mammary glands -regulation: neurosecretory cells of hypothalamus secrete OT in response to uterine distension and stimulation of nipples -function: stimulates contraction of smooth muscle cells of uterus during childbirth; stimulates contraction of myoepithelial cells in mammary glands to cause milk ejection
target, regulation, and function of antidiuretic hormone (vasopressin)
-posterior pituitary -target: kidneys, sudoriferous glands, arterioles -regulation: neurosecretory cells of hypothalamus secrete ADH in response to elevated blood osmotic pressure, dehydration, loss of blood volume, pain, or stress; inhibitors of ADH secretion include low blood osmotic pressure, high blood volume, and alcohol -function: conserves body water by decreasing urine volume; decreases water loss through perspiration; raises blood pressure by constricting arterioles
identify the posterior and anterior nerve roots
-posterior roots: contain sensory neurons which conduct nerve impulses from sensory receptors in the skin, muscles, and internal organ into the CNS; each posterior root has a swelling known as the posterior root ganglion -anterior root: contain axons of motor neurons which conduct nerve impulses from the CNS to effectors (muscles and glands)
intrapleural pressure
-pressure within the pleural cavity (space between parietal pleura and visceral pleura) -always a negative pressure (754-756mmHg) due to surface tension of alveolar fluid (fluid pulls alveoli inward (lungs recoil and pull inwards), pulling entire lung inward), elasticity of lungs, and elasticity of thoracic wall (wall pulls away from lungs)
describe the components of the synapse
-presynaptic neuron: a nerve cell that carries a nerve impulse toward a synapse -postsynaptic neuron: a cell that receives the signal -synaptic cleft: fluid-filled space separating the presynaptic and postsynaptic neurons
functions of the late distal convoluted tubule and collecting duct in reabsorption and secretion
-principal cells: reabsorb Na+ and secrete K+; have receptors for aldosterone and ADH -intercalated cells: reabsorb HCO3- and secrete H+, playing a role in blood pH regulation; reabsorb K+ -amount of water and solute reabsorbed and amount of solute secreted varies depending on the body's needs -Na+ passes through apical membrane of principal cells via Na+ leakage channels; concentration of Na+ in cytosol remains low due to Na/K pumps actively transporting Na+ across basolateral membranes; Na+ passively diffuses into peritubular capillaries from the interstitial spaces around the tubule cells -principal cells secrete variable amount of K+; basolateral Na/K pump continually bring K+ into principal cells so intracellular K+ concentration remains high; K+ leakage channels are present in both the apical and basolateral membranes so some K+ diffuses down its concentration gradient into the tubular fluid where the K+ concentration is low; main source of K+ excreted in urine
adrenergic neurons
-releases the neurotransmitter norepinephrine -released by sympathetic postganglionic neurons or released as a hormone into the blood by chromaffin cells of the adrenal medullae
compare the mucosa of the small and large intestines, including cell types and structure
-small intestine: contains plicae circularis; simple columnar epithelial tissue -large intestine: haustra; simple columnar epithelial tissue, transitional to stratified squamous epithelium in anal canal; does not have structural adaptations that increase surface area
adrenal medulla
-produces three catecholamine hormones: epinephrine, norepinephrine, and a small amount of dopamine
describe the organization of white matter into projection, association, and commissural fibres
-projection tracts: axons that conduct nerve impulses between the cerebrum and the lower parts of the CNS (thalamus, brainstem, or spinal cord) -association tracts: axons that conduct nerve impulses between gyri in the same hemisphere -commissural tracts: axons that conduct nerve impulses from gyri in one cerebral hemisphere to corresponding gyri in the other cerebral hemisphere; ex. corpus callosum, anterior commissure, posterior commissure
Sertoli cells
-protect and nourish developing sperm cell -secrete testis-determining factor which increases concentration of testosterone
main segments of renal tubule
-proximal convoluted tubule: first part of renal tubule -nephron loop: connects the PCT and DCT; descending limb of the nephron loop = begins in renal cortex and extends downward into medulla; ascending limb of the nephron loop: returns to cortex and terminates at DCT -distal convoluted tubule: last part of renal tubule; empty into collecting duct
key arteries and veins of the pulmonary circulation
-pulmonary trunk -right pulmonary artery -left pulmonary artery -pulmonary veins (4)
structure and function of venous valves and role of muscle contraction in venous blood flow
-pumping action of heart is a major factor in moving venous blood back to the heart; contraction of skeletal muscles in lower limbs helps boost venous blood return to the heart -valves: folds of tunica interna that form flaplike cusps and project into the lumen, pointing towards the heart; prevent backflow of blood
characteristics and function of ependymal cells
-range in shape from squamous to columnar -may be ciliated (cilia beat to circulate CSF) -line the central cavities of the brain and spinal column
functions of the early distal convoluted tubule in reabsorption and secretion
-reabsorbs 10-15% of filtered water, 5% of filtered Na+, 5% of filtered Cl- -Na+-Cl- symporters: reabsorb Na+ and Cl- -Na/K pumps and Cl- leakage channels in basolateral membrane permit reabsorption of Na+ and Cl- into peritubular capillaries -major site where parathyroid hormone stimulates reabsorption of Ca2+; amount reabsorbed varies depending on the body's needs
functions of the proximal convoluted tubule in reabsorption and secretion
-reabsorbs 66% of everything -Na+ symporters located in apical membrane of the first half of PCT reabsorb filtered glucose, amino acids, lactic acid, water-soluble vitamins, and other nutrients -Na+-glucose symporter: two Na+ and one glucose attach to the symporter protein which carried them from the tubular fluid into the tubule cell; glucose exits basolateral membrane via facilitated diffusion and diffuses into peritubular capillaries -Na+-H+ antiporters: carry filtered Na+ down its concentration gradient into a PCT cells as H+ is moved from the cytosol into the lumen, causing Na+ to be reabsorbed into blood and H+ to be secreted into tubular fluid -urea and ammonia are filtered at glomerulus and secreted by PCT cells into tubular fluid -deaminate glutamine to produce NH3 which is then secreted into tubular fluid
functions of the nephron loop in reabsorption and secretion
-reabsorbs about 20% of filtered water -reabsorption of water via osmosis is not automatically coupled to reabsorption of filtered solutes because part of the nephron is impermeable to water; sets stage for independent regulation of both the volume and osmolarity of body fluids -Na+-K+-2Cl- symporters: reclaim one Na+, one K+, and two Cl- from the fluid in the tubular lumen; Na+ diffuses into vasa recta; Cl- move through leakage channels into interstitial fluid then into vasa recta; K+ pass through leakage channels then back into tubular fluid
identify the three layers that surround the kidneys
-renal capsule: deep layer; smooth, transparent sheet of dense irregular connective tissue that is continuous with the other outer coat of the ureter; serves as a barrier against trauma and helps maintain the shape of the kidney -adipose capsule: middle layer; mass of fatty tissue surrounding the renal capsule; protects kidney from trauma and holds it firmly in place within the abdominal cavity -renal fascia: superficial layer; thin layer of dense irregular connective tissue that anchors the kidney to the surrounding structures and to the abdominal wall; on anterior surface of kidneys, renal fascia is deep to peritoneum
structures of the internal kidney
-renal cortex: superficial, light red region -renal medulla: deep, darker reddish-brown inner region; consists of renal pyramids -renal pyramids: cone-shaped structure in medulla; base of each pyramid faces the renal cortex; apex (renal papilla) faces renal hilum -renal columns: portions of renal cortex that extend between renal pyramids
chemoreceptors
-respond to changes in O2, CO2, and pH -central chemoreceptors: medulla oblongata; respond to a decrease in pH or an increase in CO2 in the CSF -peripheral chemoreceptors: aortic arch and carotid arteries; sensitive to decreases in O2 levels in the blood -send sensory information to the respiratory centre which activates motor neurons of respiratory muscles to increase ventilation
location and anatomy of pancreas
-retroperitoneal gland -about 12-15cm long and 2.5cm thick -lies posterior to the greater curvature of the stomach -consists of a head, body, and a tail -usually connected to the duodenum of the small intestine by two ducts
bundle branches
-right and left bundle branches -extend through the interventricular septum toward the apex of the heart
limbic system
-ring of structures on the inner border of the cerebrum and floor of the diencephalon -plays a role in a range of emotions, such as pain, pleasure, docility, affection, and anger
chemical digestion of carbohydrates in the small intestines
-salivary amylase may continue to act in stomach, however acidic pH will destroy it eventually -pancreatic amylase: cleave starches not already broken down into maltose, maltotriose, and alpha-dextrins; acts on both glycogen and starches, but not cellulose -after amylase has split starch into smaller fragments, a brush-border enzyme called alpha-dextrinase acts on the resulting alpha-dextrins, clipping off one glucose unit at a time -brush-border enzymes digest disaccharides into monosaccharides: sucrase breaks sucrose into a molecule of glucose and a molecule of fructose; lactase digests lactose not a molecule of glucose and a molecule of galactose; maltase splits maltose and maltotriose into two or three molecules of glucose respectively -digestion ends with production of monosaccharides, which the digestive system can absorb
alveolar fluid
-secreted by type II alveolar cells -keeps surface between the cells and air moist
functions of the liver
-secretes bile -carbohydrate metabolism: breakdown of glycogen -lipid metabolism: store triglycerides, break down fatty acids for ATP; lipoprotein synthesis -protein metabolism: deaminate amino acids for ATP production -processing of drugs and hormones: detoxifies substances (ie. alcohol) -excretion of bilirubin: absorbed by liver and secreted into bile -synthesis of bile salts: used in small intestine for emulsification and absorption of lipids -storage: vitamins, minerals, glycogen -phagocytosis: Kupffer cells phagocytize -activation of vitamin D: synthesizes active form of vitamin D
functions of small intestine
-segmentations mix chyme with digestive juices and bring food into contact with mucosa for absorption; peristalsis propels chyme through small intestine -completes digestion of carbohydrates, proteins, and lipids; begins and completes digestion of nucleic acids -absorbs about 90% of nutrients and water that pass through digestive system
functions of nervous system
-sensory function: sensory receptors detect internal stimuli; sensory information is carried to brain and spinal cord -integrative function: nervous system processes sensory information by analyzing it and making decisions -motor function: nervous system activates effectors causing muscles to contract and glands to secrete
describe the organization and function of the anterolateral (spinothalmic) tract
-sensory pathway from the skin to the thalamus -nerve impulses for pain, temperature, itch, and tickle from the limbs, trunk, neck, and posterior head ascend to the cerebral cortex alone the anterolateral pathway -first order neurons of the anterolateral pathway connect a receptor of the limbs, trunk, neck, or posterior head with the spinal cord -axon terminals of first order neurons synapse with second order neurons whose cell bodies are located in the posterior gray horn of the spinal cord -axons of the second order neurons cross to the opposite side of the spinal cord and pass upward to the brainstem as the spinothalmic tract -axons of the second order neurons end in the ventral posterior nucleus of the thalamus, where they synapse with the third order neurons -axons of the third order neurons project to the primary somatosensory area on the same side of the cerebral cortex as the thalamus
functional classification of neurons
-sensory: afferent neurons; either contain sensory receptors at their distal ends or are located just after sensory receptors that are separate cells; forms action potentials; most are unipolar -motor: efferent neurons; convey action potentials away from CNS to effectors; most are multipolar -interneurons: association neurons; mainly located within CNS between sensory and motor neurons; process incoming sensory information and elicit motor response by activating motor neurons; most are multipolar
SA node
-sinoatrial node -located in the right atrial wall, just inferior and lateral to the opening of the superior vena cava -pacemaker of the heart
reticular formation
-small clusters of neuronal cell bodies (gray matter) interspersed among small bundles of myelinated axons (white matter); netlike arrangement of white and gray matter -consciousness, arousal, maintaining attention, filters out insignificant information to prevent sensory overload
describe the bile duct system of the liver and gallbladder
-small ducts between hepatocytes that collect bile produced by the hepatocytes -from canaliculi, bile passes into bile ductules and then into bile ducts which merge and form right and left hepatic ducts -these unite and exit the liver as the common hepatic duct which joins the cystic duct from the gallbladder to form the common bile duct which carries bile to the duodenum
structure and function of urethra
-small tube leading from the internal urethral orifice in the floor of the urinary bladder to the exterior of the body -terminal portion of urinary system and the passageway for discharging urine from the body; in males, discharges semen as well -males: subdivided into 3 anatomical regions = prostatic urethra (passes through prostate; transitional epithelium that becomes stratified columnar or psuedostratified columnar epithelium more distally), intermediate urethra (passes through deep muscles of perineum; stratified columnar or pseudostratified columnar epithelium), spongy urethra (passes through penis; stratified columnar or pseudostratified columnar epithelium); prostatic urethra contains openings of ducts that transport secretions from prostate, seminal vesicles and vas deferens; vas deferens deliver sperm and provide secretions that neutralize acidity and contribute to sperm motility and viability; openings of bulbourethral glands empty into spongy urethra and deliver alkaline substance prior to ejaculation that neutralizes acidity of urethra -females: consists of deep mucosa and superficial muscularis; mucosa = mucous membrane composed of transitional epithelium and lamina propria ; muscularis = circularly arranged smooth muscle fibres
characteristics and function of microglia
-small, ovoid cells with thorny processes that touch and monitor neurons -migrate toward injured neurons -can transform to phagocytize microorganisms and neuronal debris
function of smooth muscle and elastic tissue in blood vessels
-smooth muscle allows for vasoconstriction and vasodilation of blood vessels -elastic tissue allows blood vessels to recoil so they can return to normal after vasoconstriction and vasodilation
somatic nervous system vs autonomic nervous system effectors
-somatic nervous system innervates skeletal muscle -autonomic nervous system innervates cardiac muscle, smooth muscle, and glands
structural and functional differences between the somatic, sympathetic, and parasympathetic nervous systems
-somatic nervous sytem: consists of somatic motor neurons; voluntary control of movement -sympathetic autonomic nervous system: stimulates the body's fight-or-flight response -parasympathetic autonomic nervous system: contrasts sympathetic autonomic nervous system; SSLUDD (sexual arousal, salivation, lacrimation, urination, digestion, defecation)
olfactory epithelium
-specialized epithelial tissue in the nasal cavity that is involved in smell -olfactory receptor cells, supporting cells, basal cells -contains cilia but not Goblet cells
briefly describe the stages of spermatogenesis
-spermatogonia undergo mitosis where some remain near the basement membrane to serve as a reservoir for future cell division, while others squeeze through the tight junctions of the blood-testis barrier and differentiate into primary spermatocytes -primary spermatocyte replicates its DNA and meiosis begins. meiosis I: homologous pairs of chromosomes line up at metaphase plater and crossing over occurs, meiotic spindle pulls them apart, creating two cells called secondary spermatocytes -secondary spermatocytes begin meiosis II: chromosomes line up along metaphase plate, two chromatids of each chromosome separate, creating four haploid cells called spermatids -cytokinesis fails and cells remain in contact via cytoplasmic bridges -spermiogenesis: final stage; development of haploid spermatids into sperm; spherical spermatids transform into elongated, slender sperm: acrosome forms, flagellum develops; mitochondria multiply -sperm are released from their connections to sustentacular cells (spermiation) -sperm enter lumen of seminiferous tubule and fluid secreted nu sustentacular cells pushes sperm along their way towards the testes
spermatogonia vs primary spermatocytes vs spermatids vs spermatozoa
-spermatogonia: stem cells that squeeze through the blood-testis barrier and differentiate into primary spermatocytes; diploid (2n) -primary spermatocytes: diploid (46 chromosomes); begins meiosis and divides into secondary spermatocytes -spermatids: four haploid cells arising from meiosis II -spermatozoa: haploid cells undergo spermatogenesis and become sperm
discuss the role of the Na/K pump in establishing the resting membrane potential
-stabilizes resting membrane potential -maintains concentration gradient for Na+ and K+ -3 Na+ pumped out of cell; 2 K+ pumped in
chemical digestion of proteins in the small intestines
-starts in stomach where proteins are fragmented into peptides by the action of pepsin -enzymes in pancreatic juice (trypsin, chymotrypsin, carboxypeptidase, elastase) continue to break down proteins into peptides -trypsin, chymotrypsin, and elastase all cleave the peptide bond between a specific amino acid and its neighbour -carboxypeptidase splits off the amino acid at the carboxyl end of a peptide -protein digestion is completed by two peptidases in the brush border: aminopeptidase (cleaves off the amino acid at the amino end of a peptide) and dipeptidase (splits dipeptides [two amino acids joined by peptide bond] into single amino acids)
spermatogonia
-stem cells -develop from primordial germ cells -undergo spermatogenesis to form mature spermatozoa
functions of testosterone
-steroid hormone synthesized from cholesterol in the testes -principal androgen -via negative feedback, suppresses secretion of LH and GnRH -5 alpha reductase converts testosterone into another androgen called dihydrotestosterone
explain the process of acid secretion by parietal cells
-stimulated by i) acetylcholine released by parasympathetic neurons ii) gastrin secreted by G cells, iii) histamine secreted by mast cells in the lamina propria -histamine acts synergistically to enhance the effects of ACh and gastrin, in turn releasing more HCl
define threshold, depolarization, repolarization, and hyperpolarization
-threshold: -55mV in most neurons; action potential occurs when this level is reached -depolarization: negative membrane potential becomes less negative, reaches zero, and then becomes positive -repolarization: membrane potential is restored to resting state of -70mV -hyperpolarization: membrane potential temporarily becomes more negative than the resting level
functional significance of histological features of esophageal wall
-stratified squamous epithelium: protection against abrasion and wear and tear from food particles that are chewed, mixed and swallowed -submucosal glands: secrete mucus that protects the esophagus from stomach acid -muscularis layer of smooth and skeletal muscle: skeletal muscle forms upper esophageal sphincter (regulates movement of food from pharynx into esophagus); smooth muscle forms lower esophageal sphincter (regulates movement of food from esophagus into stomach) -adventita: superficial layer of esophagus; attaches esophagus to surrounding structures
neurotransmitter: neuropeptides
-substance P: mediator of pain signals -endorphins: beta endorphin, dynorphin, and enkephalins; act as natural opiates; reduces pain perception -gut-brain peptides: somatostatin and cholecystokinin -released by CNS neurons
nasopharynx
-superior portion of the pharynx -lies posterior to the nasal cavity and extends to the soft palate, forming posterior portion of the roof of the mouth -5 openings: two internal nares, two openings leading into the auditory tubes, opening into oropharynx -posterior wall also contains pharyngeal tonsils (adenoids) -receives air and packages of dust-laden mucous from the nasal cavity; exchanges small amount of air with the auditory tubes to equalize pressure between the middle ear and atmosphere -lined with ciliated pseudo stratified columnar epithelium
route of blood flow through the heart and the systemic and pulmonary circulations
-superior vena cava (blood from above heart), inferior vena cava (blood from below heart), and coronary sinus (blood from the heart) deliver blood to right atrium -right atrium pumps blood to right ventricle through tricuspid valve -right ventricle pumps blood to pulmonary artery through pulmonary valve, which delivers deoxygenated blood to lungs -pulmonary veins deliver oxygenated blood to left atrium -left atrium pumps blood to left ventricle through bicuspid (mitral) valve -left ventricle pumps blood to aorta through aortic valve, which delivers blood to the entire body and back to right atrium eventually
describe the rest-and-digest response of the parasympathetic nervous system
-support body functions that conserve and restore body energy during times of rest and recovery -in the quiet intervals between period of exercise, parasympathetic impulses to the digestive glands and smooth muscle of GI tract predominate over sympathetic impulses -allows energy-supplying food to be digested and absorbed while reducing body functions that support physical activity -SLUDD: salivation, lacrimation, urination, digestion, defecation
locate the scrotum and discuss its function in regulating the temperature for sperm production
-supporting structure for the testes; consists of loose skin and underlying subcutaneous layer that hands from the root of the penis -normal sperm production requires temperature of ~34C; maintained within the scrotum because it is outside the pelvic cavity -in response to cold temperatures, cremaster muscles contract and move the testes closer to the body where they absorb body heat; contraction of dartos muscle causes scrotum to become tight, reducing heat loss -exposure to warmth reverses these reactions
secretions of cells of the gastric glands and their functions
-surface mucous cells & mucous neck cells: secrete mucus = forms protective barrier that prevents digestion of stomach wall; absorption = small quantity of water, ions, and fatty acids -parietal cells: secrete intrinsic factor = absorption of vitamin B12; secret HCl = kills microbes in food, denatures proteins, coverts pepsinogen into pepsin -chief cells: secrete pepsinogen = pepsin (active form) breaks down proteins into peptides; secrete gastric lipase = splits triglycerides into fatty acids and monoglycerides -G cells: secrete gastrin = stimulates parietal cells to secrete HCl and chief cells to secrete pepsinogen; contracts lower esophageal sphincter, increases motility of stomach, and relaxes pyloric sphincter
identify the posterior root ganglion
-swellings at the ends of posterior nerve roots -contain the cell bodies of sensory neurons
define systole and diastole
-systole: phase of contraction -diastole: phase of relaxation
targets, regulation, and function of thyroid hormone [triiodothyronine and tetraiodothyronine (T3 and T4)]
-target: tissues all throughout the body -regulation: secretion is increased by thyrotropin-releasing hormone (TRH), which stimulates release of thyroid-stimulating hormone (TSH) in response to low thyroid hormone levels, low metabolic rate, cold, pregnancy, and high altitudes; TRH and TSH secretions are inhibited in response to high thyroid hormone levels; high iodine level suppresses T3/T4 secretion -function: increase basal metabolic rate; stimulate synthesis of proteins; increase use of glucose and fatty acids for ATP production; increase lipolysis; enhance cholesterol excretion; accelerate body growth; contribute to development of nervous system
chordae tendineae
-tendonlike cords that are connected to cusps of tricuspid valve and to papillary muscles (cone-shaped trabeculae carneae) -found in right ventricle
identify the respiratory airways of the bronchial tree
-terminal bronchioles and lobules (compartments of bronchiopulmonary segments) subdivide into microscopic branches called respiratory bronchioles -respiratory bronchioles subdivide into alveolar ducts; simple squamous epithelium
alveolar sacs
-terminal dilation of alveolar ducts -composed of outpouchings called alveoli -"cluster of grapes"
interatrial septum
-thin partition separating the left and right atria -fossa ovalis: oval depression in the interatrial septum, a remnant of the foramen ovale (opening in the fetal heart that closes after birth)
basal nuclei
-three nuclei (masses of gray matter) deep within each cerebral hemisphere -two of the basal nuclei lie side by side, just lateral to the thalamus (globus pallidus); putamen is lateral to globus pallidus; together, they make up the lentiform nucleus -caudate nucleus: third basal nucleus; has a large head connected to a smaller tail -lentiform and caudate nuclei form the corpus striatum
describe the structure, function, and cell types of the alveoli
-tiny air sacs at the end of bronchioles -site of gas exchange (CO2 & O2) -contains type I alveolar cells, type II alveolar cells, alveolar macrophages in walls -type I alveolar cells: more numerous; simple squamous epithelial cells; form lining of alveolar wall; main sites of gas exchange -type II alveolar cells: found between type I alveolar cells; cuboidal epithelial containing microvilli; secrete alveolar fluid and surfactant -alveolar macrophages: phagocytes that remove fine dust particles and other debris from fibres
identify the conducting airways of the bronchial tree
-trachea divides into right and left main (primary) bronchi; right primary bronchus leads to right lung; left primary bronchus leads to left lung; contain incomplete rings of cartilage and are lined with ciliated pseudostratified columnar epithelium -in the lungs, primary bronchi divide to form smaller bronchi- lobar (secondary) bronchi; one for each lobe of the lung (R=3; L=2) -secondary bronchi continue to branch, forming mental (tertiary) bronchi; supply specific bronchopulmonary segments within the lobes -segmental bronchi then divide into bronchioles -bronchioles branch repeatedly, and the smallest ones branch into even smaller tubes called terminal bronchioles; contain club (Clara) cells that protect against harmful effects of inhaled toxins and carcinogens, produce surfactant, and function as stem cells; represent end of conducting zone of the bronchial tree
structure and function of ureters
-transports urine from the renal pelvis of one kidney to the urinary bladder with the help of peristaltic contractions, hydrostatic pressure, and gravity -paired; 25-30 cm long; thick walled, narrow tubes -retroperitoneal -3 layers: mucosa, muscularis, adventitia -mucosa: deepest layer; mucous membrane with transitional epithelium and underlying lamina propria of areolar connective tissue with collagen, elastic fibres, and lymphatic tissue -muscularis: intermediate layer; inner longitudinal and outer circular smooth muscle fibres (opposite to GI tract); functions in peristalsis -adventitia: superficial layer; areolar connective tissue containing blood vessels, lymphatic vessels, and nerves that serve the muscularis and mucosa; anchors ureters in place
location, structure, and function of atrioventricular valves
-tricuspid valve (RA to RV) and bicuspid valve (LA to LV) -when AV valve is open, rounded cusps project into the ventricle- ventricles are relaxed, papillary muscles are relaxed, chordae tendineae are slack, and blood moves from a higher pressure in the atria to a lower pressure in the ventricles -when ventricles contract, pressure of blood drives the cusps upward until their edges meet and close the opening. at the same time, papillary muscles contract, which pulls on and tightens the chordae tendineae, preventing the cusps from inverting (opening into atria) in response to high ventricular pressure
describe the components of the layers of the blood vessel wall
-tunica interna: innermost lining of a blood vessel; in direct contact with blood; composed of 1) endothelial cells = inner lining; has physical influence on blood flow, secretes locally acting chemical mediators that influence the contractile state of the vessel's overlying smooth muscle, assist with capillary permeability, and their smooth surface helps avoid friction as blood passes through, and 2) basement membrane = deep to endothelium; physical support for epithelium, collagen fibres give it tensile strength, provide resilience for stretching and recoil; internal elastic lamina forms barrier between tunica interna and tunica media and facilitate diffusion of materials between the layers -tunica media: middle layer; muscular and connective tissue layer; in most vessels, a relatively thick layer comprising mainly of smooth muscle cells and elastic fibres; regulates diameter of lumen (vasoconstriction and vasodilation) and vascular spasm to prevent blood loss -tunica externa: outermost lining; consists of elastic and collagen fibres; contains numerous nerves and tiny blood vessels (vasa vasorum) that supply the tissue of the vessel wall; helps anchor vessels to surrounding tissue
function of uterine (fallopian) tubes
-two tubes that extend laterally from the uterus; ~10 cm long; lie within the folds of the broad ligaments of the uterus -transports ova from ovary to the uterus -transports fertilized egg to uterus for implantation
describe the migrating motility complex
-type of peristalsis that occurs in the small intestine after a meal has been absorbed and segmentation has stopped -begins in the lower portion of the stomach and pushes chyme forward along a short stretch of small intestine before dying out -MMC slowly migrates down the small intestine, reaching the end of the ileum in 90-120 minutes. then another MMC begins in the stomach. altogether, chyme remains in the small intestine for 3-5 hours
role of ADH and medullary osmotic gradient in the urine concentrating abilities of the kidneys
-under influence of ADH, kidneys produce a small volume of highly concentrated urine -ability of ADH to cause excretion of concentrated urine depends on osmotic gradient of solutes in interstitial fluid of renal medulla -3 major solutes that contribute to high osmolarity in renal medulla: Na+, Cl-, and urea -2 major factors of osmotic gradient: 1) differences in solute and water permeability and reabsorption in different sections of the long nephron loops and the collecting ducts, and 2) the countercurrent flow (flow of fluid in opposite directions) of fluid through tube-shaped structures in the renal medulla
identify the structures of the upper and lower respiratory tracts
-upper: nose, nasal cavity, pharynx, and associated structures -lower: larynx, trachea, bronchi, lungs
functional significance of mucus in small intestine
-used as a lubricant to help move food along -protects cells against gastric juices
effects of progesterone
-uterine endometrium becomes secretory which provides source of nutrients to blastocyte -allows cervical mucus to become thick, sealing off the uterus from further entry of sperm -allow basal body temperature to increase by 0.5-1F
describe the function of the ANS in the regulation of gastrointestinal function
-vagus (X) nerve supply parasympathetic fibres to most parts of the GI tract with the exception of the last half of the small intestine; parasympathetic nerves that supply the GI tract form neural connections with the ENS; stimulation of the parasympathetic nerves that innervate the GI tract causes an increase in GI secretion and motility by increasing the activity of ENS neurons -sympathetic nerves arise form thoracic and lumbar regions of spinal cord; form neural connections with ENS; sympathetic postganglionic neurons synapse with neurons located in the myenteric plexus and submucosal plexus; cause a decrease in GI secretions by inhibiting neurons of the ENS; emotions such as anger, fear, and anxiety may slow digestion because they stimulate the sympathetic nerves that supply the GI tract
describe how the wall layers of blood vessel walls differ between arteries and veins
-veins have thinner walls -veins lack internal or external elastic laminae found in arteries -tunica interna of veins forms flaplike cusps called valves that prevent backflow of blood -lumen of vein is larger than artery
describe the relationship between cross sectional area and the velocity of blood flow
-velocity: speed of blood flow -velocity is slowest where the total cross-sectional area is greatest because blood moves slower as it moves further away from the heart -when venules unite to form veins, the total cross-sectional area becomes smaller and the velocity increases
stroke volume
-volume of blood ejected by the ventricle during each contraction -70mL/beat in average male
cardiac output
-volume of blood ejected from the left ventricle into the aorta, or from the right ventricle into the pulmonary trunk -5.25L/min in average male -CO = SV x HR
describe the epithelial layer of the small intestine
-wall of small intestine composed of 4 layers: mucosa, submucosa, muscularis, and serosa -simple columnar epithelium that contain many different types of cells
alveoli
-walls consists of two types of alveolar epithelial cells: type I alveolar and type II alveolar; alveolar macrophages -"individual grape"
conus medullaris
-where the spinal cord terminates -tapering, cone-shaped structure which ends at the level of the intervertebral discs of L1-L2
identify anatomical features seen in a cross-sectional view of the spinal cord
-white matter: bundles of myelinated axons -anterior median fissure: wide groove on the anterior side -posterior median sulcus: narrow furrow on the posterior side -gray matter: dendrites, cell bodies of neurons, unmyelinated axons, & neuroglia -gray commissure: forms crossbow of H in gray matter -central canal: small space in gray commissure that extends the entire length of the spinal cord and is filled with cerebrospinal fluid -anterior white commissure: anterior to the gray commissure and connects the white matter of the right and left sides of the spinal cord
composition of white and gray matter
-white matter: regions of the brain and spinal cord with dense collections of myelinated fibres -gray matter: mostly neuron cell bodies and nonmyelinated fibers
characteristics and function of Schwann cells
-wrap around axon in jelly roll fashion -one cell forms one segment of myelin sheath
pulmonary capillary
-wraps around the alveoli in the lungs -gets rid of carbon dioxide and picks up oxygen
composition and function of bile
-yellow, brownish, or olive green liquid -pH of 7.6-8.6 -consists mostly of water, bile salts, cholesterol, lecithin, bile pigments, and several ions -function: digestion and absorption of lipids
explain the electrical events of a normal ECG
1) a cardiac action potential arises in the SA node, and propagates throughout the atrial muscle and down to the AV node in about 0.03 sec. as atrial contractile fibres depolarize, the P wave appears in ECG 2) after P wave begins, atria contract (atrial systole). conduction of action potential slows at the AV node because the fibres there have much smaller diameters and fewer gap junctions. resulting 0.1 sec delay gives the atria time to contract, adding to the volume of blood in the ventricles, before ventricular systole begins 3) action potential propagates rapidly before entering AV bundle. depolarization progresses down the septum, upward from the apex, and outward from the endocardial surface, producing the QRS complex. at the same time, atrial repolarization is occurring but it is not evident in ECG because larger QRS masks it 4) contraction of ventricular contractile fibres (ventricular systole) begins shortly after the QRS complex appears and continues during the S-T segment. as contraction proceeds from apex toward the base of the heart, blood is squeezed upward toward the semilunar valves 5) repolarization of ventricular contractile fibres begins at the apex and spreads throughout the ventricular myocardium. this produces the T wave in the ECG about 0.4 sec after the onset of the P wave 6) shortly after the T wave begins, the ventricles start to relax (ventricular diastole). by 0.6 sec, ventricular repolarization is complete and ventricular contractile fibres are relaxed
mechanism of action on target cells by lipid-soluble hormones
1) a free lipid soluble hormone molecule diffuses from the blood, through interstitial fluid, and through the lipid bilayer of the plasma membrane into the cell 2) if the cell is a target cell, the hormone binds to and activates receptors located within the cytosol/nucleus. the activated receptor-hormone complex then alters gene expression, turning specific genes of the nuclear DNA on or off 3) as DNA is transcribed, new mRNA forms, leaves the nucleus, and enters the cytosol. there, it directs synthesis of a new protein on the ribosomes 4) new proteins alter the cell's activity and cause the responses typical of that hormone
mechanism of action on target cells by water-soluble hormones
1) a water soluble hormone diffuses from the blood through interstitial fluid and then binds to its receptor at the exterior surface of a target cell's plasma membrane. the hormone-receptor complex activated a membrane protein called a G protein. the activated G protein in turned activates adenylyl cyclase 2) adenylyl cyclase converts ATP into cyclic AMP. because the enzyme's active site is on the inner surface of the plasma membrane, this reaction occurs in the cytosol of the cell 3) cyclic AMP activates one or more protein kinases (enzyme that phosphorylates) 4) activated proteins kinases phosphorylate one or more cellular proteins, activating some of the proteins and inactivating others 5) phosphorylated proteins in turn cause reactions that produce physiological responses. different protein kinases exist within different target cells and within different organelles of the same target cell 6) after a brief period, an enzyme called phosphodiesterase inactives cAMP. thus, the cell's response is turned off unless new hormone molecules continue to bind to their receptors in the plasma membrane
discuss the mechanics of inhalation and exhalation
1) at rest, when the diaphragm is relaxed, alveolar pressure (760mmHg) is equal to atmospheric pressure (760mmHg), and there is no air flow 2) during inhalation, the diaphragm and external intercostals contract, expanding the chest cavity. alveolar pressure (758mmHg) drops below atmospheric pressure. air flows into the lungs in response to the pressure gradient and the lung volume expands. during deep inhalation, the scalene and sternocleidomastoid muscles expand the chest further, creating a greater drop in alveolar pressure 3) during exhalation, the diaphragm and external intercostals relax. chest and lungs recoil, chest cavity contracts, and the alveolar pressure increases (762mmHg) above atmospheric pressure. air flows out of the lungs in response to the pressure gradient, and the lung volume decreases. during forced exhalations, the internal intercostals and abdominal muscles contract, reducing the size of the chest cavity further and creating a greater increase in alveolar pressure
regulation of heart rate
1) autonomic regulation: originates in cardiovascular system of medulla oblongata; proprioceptors (monitor position of limbs and muscles), chemoreceptors (monitor chemical changes in blood), baroreceptors (monitor stretching of blood vessels) 2) chemical regulation: hormones = epinephrine and norepinephrine enhance heart rate; cations = elevated blood levels of K+ and Na+ decrease heart rate, increase in Ca++ in interstitial fluid speeds heart rate 3) other regulation: age, gender, physical fitness, and body temperature influence heart rate
types of shock
1) hypovolemic shock: due to decreased blood volume 2) cardiogenic shock: due to poor heart function 3) vascular shock: due to inappropriate vasodilation 4) obstructive shock: due to obstruction of blood flow
describe the pacemaker cell action potential
1) cardiac excitation begins in the SA node. SA node cells do not have a stable resting potential, instead rapidly depolarizing to threshold spontaneously (pacemaker potential). when the pacemaker potential reaches threshold, it triggers an action potential which propagates from the SA node throughout both atria via gap junctions in the intercalated discs of atrial muscle fibres. following the action potential, the two atria contract at the same time 2) by conducting along atrial muscle fibres, the action potential reaches the atrioventricular (AV) node where it slows considerably as a result of various differences in cell structure in the AV node. this delay provides time for the atria to empty their blood into the ventricles 3) from the AV node, the action potential enter the atrioventricular (AV) bundle (aka bundle of His) 4) after propagating through the AV bundle, the action potential enters both the right and left bundle branches, which extend through the interventricular septum towards the apex of the heart 5) finally, Purkinje fibres rapidly conduct the action potential beginning at the apex of the heart upward to the remainder of the ventricular myocardium. then, ventricles contract and push the blood upward toward the semilunar valves
regulation of blood pressure
1) cardiovascular centre: helps regulate heart rate and stroke volume; controls neural, hormonal, and local negative feedback systems that regulate BP and blood flow; groups of neurons within the CV centre regulate heart rate, contractility of the ventricles, and blood vessel diameter; some neurons stimulate while some inhibit; receives input from higher brain regions and sensory receptors, and sends output along sympathetic and parasympathetic neurons 2) neural regulation: baroreceptor reflexes = pressure-sensitive sensory receptors located in the aorta, internal carotid arteries, and other large arteries in the neck and chest that send impulses to the CV centre to help regulate BP, two most important are carotid sinus reflex and aortic reflex; chemoreceptor reflexes = sensory receptors that monitor the chemical composition of blood, located near baroreceptors 3) hormonal regulation: renin-angiotensin-aldosterone (RAA) system = when blood volume falls low, kidneys secrete renin > renin and angiotensin-converting enzyme (ACE) produce angiotensin II > angiotensin II stimulates secretion of aldosterone; epinephrine and norepinephrine = in response to sympathetic stimulation, adrenal medulla secretes E & NE to increase cardiac output; antidiuretic hormone (ADH) = produced by hypothalamus and released from the posterior pituitary in response to dehydration or decreased blood volume, causing vasoconstriction; atrial natriuretic peptide (ANP) = released by the cells in the atria of the heart to lower BP by causing vasodilation and promoting the loss of salt and water in the urine 4) autoregulation: through vasodilators and vasoconstrictors, a tissue can automatically adjust its blood flow to match its metabolic demands; stimulated by physical changes (warming, cooling), and vasodilating (K+, H+, lactic acid, adenosine) and vasoconstricting (thromboxane A2, serotonin, superoxide radicals, endothelins) chemicals
organization of nervous system
1) central nervous system = brain and spinal cord -processes many different kinds of incoming sensory information -source of thoughts, emotions and memories -produces signals causing muscles to contracts and glands to secrete 2) peripheral nervous system = consists of all nervous tissue outside the CNS -further divided into sensory (afferent) division [provides information about somatic senses] and motor (efferent) division [conveys output from CNS to effectors] -efferent division is further divided: somatic nervous system (conveys output from CNS to skeletal muscle) and autonomic nervous system (conveys output from CNS to smooth muscle, cardiac muscle, and glands) -autonomic nervous system is further divided: sympathetic nervous system and parasympathetic nervous system (usually have opposing actions)
describe the three phases of digestion, and the roles of the nervous and endocrine systems in regulating these phases
1) cephalic phase: smell, sight, thought, or initial taste of food activate neural centres and prepares mouth and stomach for food to be eaten; activity of higher brain centres, acting via the vagus (X) nerve, stimulate gastric secretion 2) gastric phase: neural and hormonal mechanism promote gastric secretion and motility; secretion of HCl and pepsin is controlled by the gastric contents and by hormone gastrin, secreted by the gastric mucosa 3) intestinal phase: food enters small intestine and slows exit of chyme from stomach; stimulates flow of bile and pancreatic juice; activity of stomach is inhibited by neural reflexes and hormonal secretion from the duodenum
explain how an action potential occurs in cardiac muscle fibres
1) depolarization: contractile fibres have a stable resting membrane potential of -90mV. rapid depolarization due to Na+ inflow when voltage-gated fast Na+ channels open 2) plateau: (maintained depolarization) due to Ca2+ inflow when voltage-gated slow Ca2+ channels open and K+ outflow when some K+ channels open 3) repolarization: due to closure of Ca2+ channels and K+ outflow when additional voltage-gated K+ channels open
explain the three ways in which neurotransmitter activity is stopped
1) diffusion: some of the released neurotransmitter molecules diffuse away from the synaptic cleft. once out of reach of its receptors, the neurotransmitter can no longer exert an effect 2) enzymatic degredation: certain neurotransmitters are inactivated through enzymatic degradation; ex. acetylcholinesterase breaks down acetylcholine 3) uptake by cells: many neurotransmitters are actively transported back into the neuron that released them (reuptake) or into the neighbouring neuroglia (reuptake)
pressures that determine net filtration
1) glomerular blood hydrostatic pressure (GBHP): blood pressure in glomerular capillaries; ~55mmHg; promotes filtration by forcing water and solutes in blood plasma through the filtration membrane 2) capsular hydrostatic pressure (CHP): hydrostatic pressure exerted against filtration membrane by fluid already in the capsular space and renal tubule; opposes filtration; ~15mmHg 3) blood colloid osmotic pressure (BCOP): due to presence of proteins (albumins, globulins, fibrinogens) in blood plasma; opposes filtration; ~30mmHg net filtration = GBHP - CHP - BCOP = 10mmHg
urine formation
1) glomerular filtration: water and most solutes in blood plasma move across the wall of glomerular capillaries, where they are filtered and move into the glomerular capsule and then into the renal tubule 2) tubular reabsorption: as filtered fluid flows through renal tubules and collecting ducts, tubule cells reabsorb about 99% of the filtered water and many useful solutes. water and solutes return to blood as it flows through the peritubular capillaries and vasa recta 3) tubular secretion: as filtered fluid flows through renal tubules and collecting ducts, the renal tubules and duct cells secrete other materials, such as wastes, drugs, and excess ions, into the fluid
functions of digestive system
1) ingestion: taking food into the mouth 2) secretion: release of water, acid, buffers, and enzymes into lumen of GI tract 3) mixing & propulsion: churning and movement of food through GI tract 4) digestion: mechanical and chemical breakdown of food 5) absorption: passage of digested from GI tract into blood and lymph 6) defecation: elimination of feces from GI tract
describe the synthesis of thyroid hormone
1) iodide trapping: thyroid follicular cells trap iodide ions by actively transporting them from the blood into the cytosol 2) synthesis of thyroglobulin: while follicular cells are trapping iodide, they are also synthesizing thyroglobulin (TGB), a large glycoprotein that is produced in the rough ER, modified in the Golgi complex and packaged into secretory vesicles. the vesicles then undergo exocytosis, which releases TGB into the lumen of the follicle 3) oxidation of iodide: negatively charged iodide ions cannot bind to tyrosine (amino acid that will become iodinated in TGB) until they undergo oxidation to become iodine. as the iodine ions are oxidized, they pass through the membrane into the lumen of the follicle 4) iodination of tyrosine: as iodine atoms form, they react with tyrosines that are part of the thyroglobulin molecules. binding of one iodine atom yields monoiodotyrosine (T1) and a second iodination produces diiodotyrosine (T2). the TGB with attached iodine atoms is stored in the lumen of the thyroid follicle and is called a colloid 5) coupling of T1 and T2: during the last step in the synthesis of thyroid hormone, two T2 molecules going to form T4, or one T1 and one T2 join to form T3 6) pinocytosis and digestions of colloid: droplets of colloid reenter follicular cells by pinocytosis and merge with lysosomes. digestive enzymes in the lysosomes break down TGB, cleaving off molecules of T3 and T4 7) secretion of thyroid hormones: because T3 and T4 are lipid-soluble, they diffuse through the plasma membrane and into interstitial fluid and then into the blood
functions of cerebrospinal fluid
1) mechanical protection: serves as a shock-absorbing medium that protects tissues of the brain and spinal cord from jolts that would otherwise cause them to hit the bony walls of the cranial cavity and vertebral canal; also buoys the brain so it "floats" in cranial cavity 2) chemical protection: provides an optimal chemical environment for accurate neuronal signaling 3) circulation: exchange of nutrients and waste products between the blood and adjacent nervous tissue
structure and function of four wall layers of the GI tract
1) mucosa: inner lining; composed of: i) epithelium = mainly nonkeratinized stratified squamous epithelium and simple columnar epithelium in stomach and intestines ii) lamina propria = areolar connective tissue containing blood and lymphatic vessels iii) muscular mucosae = layer of smooth muscle that increases surface area for digestion and absorption 2) submucosa: areolar connective tissue that binds the mucosa to the muscularis; contains blood and lymphatic vessels that receive absorbed food molecules 3) muscularis: skeletal muscle in the mouth, pharynx, and superior and middle parts of the esophagus that produce voluntary swallowing; skeletal muscle of anal sphincter which allows voluntary control of defecation; throughout the rest of the tract, muscularis is smooth muscle which allows for breakdown of food, mixing of food with digestive secretions, and movement of food down the tract
steps involved in neurotransmission
1) nerve impulse arrives at synaptic end bulb of a presynaptic axon 2) depolarizing phase opens voltage-gated Ca2+ channels, causing Ca2+ to flow inward 3) increase in concentration of Ca2+ inside the presynaptic neuron serves as a signal that triggers exocytosis of synaptic vesicles. vesicle membranes merge with plasma membrane, releasing neurotransmitter molecules into the synaptic cleft 4) neurotransmitter molecules diffuse across the synaptic cleft and bind the neurotransmitter receptors in the postsynaptic neuron's plasma membrane 5) binding of neurotransmitter molecules to their receptors on ligand-gated channels opens the channels and allows particular ions to flow across the membrane 6) as ions flow through the opened channels, the voltage across the membrane changes (called a postsynaptic potential). depending on which ions the channels admit, this could be a depolarization or a hyperpolarization 7) when a depolarizing postsynaptic potential reaches threshold, it triggers an action potential in the axon of the postsynaptic neuron
regulation of stroke volume
1) preload: a greater preload (stretch) on cardiac muscle fibres prior to contraction increases their force of contraction; the more the heart fills with blood during diastole, the greater the force of contraction during systole, known as the Frank-Starling law of the heart 2) contractility: the strength of contraction at any given preload; increase contractility = positive inotropic agents, decrease contractility = negative inotropic agents; positive inotropic agents promote Ca++ inflow during cardiac action potentials; negative inotropic agents are stimulated by SANS, acidosis, anoxia, and increased K+ levels in interstitial fluid 3) afterload: the pressure that must be overcome before a semilunar valve can open; higher pressure in ventricles compared to aorta/pulmonary trunk causes blood to push the semilunar valves open; increased afterload = decreased stroke volume; increased afterload caused by hypertension and narrowing of arteries by atherosclerosis
components of reflex arc
1) sensory receptor: dendrite or an associated sensory structure; responds to specific stimulus by producing a graded potential called a generator potential (if this reaches the threshold, it will trigger one or more nerve impulses in the sensory neuron) 2) sensory neuron: nerve impulses propagate from the sensory receptor along the axon of the sensory neuron to the axon terminals. from here, relay neurons send nerve impulses to the area of the brain that allows conscious awareness that the reflex has occurred 3) integrating centre: one or more regions of gray matter within the CNS 4) motor neuron: impulses triggered nu the integrating centre propagate out of the CNS along a motor neuron to the part of the body that will respond 5) effector: part of the body that responds to the motor nerve impulse; action is called a reflex; if effector is skeletal muscle, reflex is a somatic reflex; if effector is smooth muscle, cardiac muscle, or gland, reflex is autonomic reflex
example of a reflex arc (stretch reflex)
1) slight stretching of a muscle stimulates sensory receptors in the muscle called muscle spindles. these monitor changes in the length of the muscle. 2) in response to being stretched, a muscle spindle generates one or more nerve impulses that propagate along a somatic sensory neuron through the posterior root of the spinal nerve and into the spinal cord 3) in the spinal cord, the sensory neuron makes an excitatory synapse with (and thereby activates) a motor neuron in the anterior gray horn 4) if the excitation is strong enough, one or more nerve impulses arises in the motor neuron and propagates, along its axon, which extends from the spinal cord into the anterior root and through peripheral nerves to the stimulated muscle. the axon terminals of the motor neurone form the NMJs with skeletal muscle fibres of the stretched muscle 5) acetylcholine released by the nerve impulses at the NMJs triggers one or more muscle action potentials in the stretched muscle and the muscle contracts. thus, muscle stretch is followed by muscles contraction, which relieves the stretching
factors that influence ventilation
1) surface tension of alveolar fluid: alveolar fluid coats luminal surface of alveoli and exerts force called surface tension; arises at air-water interfaces; liquid surrounds air and produces inwardly directed force causing alveoli to assume smallest possible diameter; surface tension must be overcome during breathing to expand the lungs 2) compliance of lungs: refers to how much effort is required to stretch the lungs and chest wall; low compliance = issues with elasticity and surface tension; lungs normally have high compliance due to elastic fibres and surfactant 3) airway resistance: airflow = pressure difference between the alveoli and atmosphere divided by the resistance; larger-diameter airways have decreased resistance; airway diameter is also regulated by degree of relaxation or contraction of smooth muscle in walls; signals from AND cause bronchodilation
describe the protective structures of the spinal cord
1) vertebral column: vertebrae provide a sturdy shelter for the enclosed spinal cord; vertebral ligaments, meninges, and cerebrospinal fluid all add additional protection 2) meninges: three protective, connective tissue coverings that encircle the spinal cord; from superficial to deep = dura mater, arachnoid mater, pia mater
describe the three stages involved in deglutition
1) voluntary stage: bolus is forced to the back of the oral cavity and into the oropharynx by the movement of the tongue upward and backward against the palate 2) pharyngeal stage: bolus stimulates receptors in the oropharynx which send impulses to the deglutition centre in the medulla oblongata; soft palate and uvula move upward and close off nasopharynx; epiglottis closes off the opening to the larynx and the bolus moves through the oropharynx and laryngopharynx; once the upper esophageal sphincter relaxes, the bolus enters the esophagus 3) esophageal stage: bolus enters the esophagus and peristalsis pushes it onward
myelination of neurons in CNS vs myelination of neurons in PNS
CNS: an oligodendrocyte puts forth about 15 broad, flat processes that spiral around CNS axons, forming myelin sheath PNS: a Schwann cell spirals around an axon many times, forming myelin sheath. The outer nucleated cytoplasmic layer of the Schwann cell is the neurolemma, found only in PNS
describe how cerebrospinal fluid is recycled
CSF is gradually reabsorbed into the blood through arachnoid villi (fingerlike extensions of the arachnoid mater that project into the dural venous sinuses)
role of voltage-gated Na+ channels in the depolarization phase
Na+ channels open first, allowing Na+ to rush into the cell, causing the depolarizing phase
osmolarity
a measure of the total number of dissolved particles per litre of solution
function of bulbourethral gland
adds fluids to semen during process of ejaculation
adrenal cortex
adrenal cortex -produces steroid hormones that are essential for life -subdivided into three zones, each of which secretes different hormones
role of voltage-gated K+ channels in the repolarization phase
after depolarization, K+ channels open, allowing K+ to flow out, causing the repolarizing phase
key arteries and veins of the systemic circulation
arteries -aorta and its branches: ascending aorta, arch of aorta, thoracic aorta, abdominal aorta -brachiocephalic: right and left subclavian artery, internal thoracic artery, vertebral artery, axillary artery, brachial artery, radial artery, ulnar artery, right and left common carotid, external and internal carotid artery veins -coronary sinus -superior vena cava -inferior vena cava
explain how blood pressure changes throughout the circulation
as blood leaves the aorta and flows through the systemic circulation, its pressure falls progressively as the distance from the left ventricle increases. BP in aorta and arteries is 110/70. BP decreases to ~35mmHg as blood passes from systemic arteries through systemic arterioles and into capillaries, where pressure fluctuations disappear. at the venous end of capillaries, BP drops to 16mmHg. BP continues to drop as blood enters systemic venules and then veins. finally, BP reaches 0mmHg as blood flows into the right ventricle.
explain how the spinal nerves are connected to the spinal cord
as spinal nerves branch from the spinal cord, they pass laterally to exit the vertebral canal through the intervertebral foramina. nerves arising from the lumbar, sacral, and coccygeal regions angle inferiorly alongside the filum terminale in the vertebral column because the spinal cord is shorter than the vertebral column so these nerves do not leave the column at the same place they exit the spinal cord.
describe the phases of a cardiac cycle
atrial systole: 1) depolarization of the SA node causes atrial depolarization, marked by the P wave in the ECG 2) atrial depolarization causes atrial systole. as the atria contract, they exert pressure on the blood within, which forces blood through the open AV valves into the ventricles 3) atrial systole contributes a final 25 mL of blood to the volume already in each ventricle (~105 mL). the end of atrial systole is also the end of ventricular diastole (relaxation). thus, each ventricle contains about 130 mL at the end of its relaxation period (diastole). this blood is called end-diastolic volume 4) the QRS complex in the ECG marks the onset of ventricular depolarization ventricular systole: 5) ventricular depolarization causes ventricular systole. as ventricular systole begins, pressure rises inside the ventricles and pushes blood up against the AV valves, forcing them shut. for about 0.5 sec, both the SL and AV valves are closed. this is the period of isovolumetric contraction. during this, cardiac muscle fibres are contracting and exerting force but are not shortening yet. thus, the muscle contraction is isometric and because all four valves are closed, the volume remains the same (isovolumic) 6) continued contraction of the ventricles causes pressure inside the chambers to rise sharply. when left ventricular pressure surpasses aortic pressure (~80mmHg) and right ventricular pressure rises above the pressure in the pulmonary trunk (~20mmHg), both SL valves open and ejection of blood from the heart begins. the period when SL valves are open is called ventricular ejection and lasts for about 0.25 sec. pressure in left ventricle rises to about 120 mmHg and pressure in right ventricle rises to about 25-30 mmHg 7) left ventricle ejects about 70mL of blood into the aorta and the right ventricle ejects the same volume of blood into the pulmonary trunk. the volume remaining in each ventricle is about 60mL and is called the end-systolic volume 8) the T wave in the ECG makes the onset of ventricular repolarization relaxation period: 9) ventricular repolarization causes ventricular diastole. as ventricles relax, pressure within the chambers falls, and blood in the aorta and pulmonary trunk begins to flow backward toward the regions of lower pressure in the ventricles. backflowing blood catches in the valve cusps and closes the SL valves. the aortic valve closes at a pressure of ~100 mmHg. rebound of blood off the closed cusps of the aortic valve produces the dicrotic wave on the aortic pressure curve. after SL valves close, there is a brief interval when ventricular blood volume does not change because all four valves are closed. this period is called isovolumetric reaction 10) a's ventricles continue to relax, the pressure falls quickly. when ventricular pressure drops below atrial pressure, the AV valves open and ventricular filling begins. the major part of ventricular filling occurs just after the AV valves open. blood that has been flowing into and building up in the atria during ventricular systole then rushes rapidly into the ventricles. at the end of the relaxation period, ventricles are about three-quarters full. the P wave appears in the ECG, signaling the start of another cardiac cycle
organization of white and gray matter in brain and spinal cord
brain: white matter = deep; gray matter = superficial spinal cord: white matter = superficial; gray matter = deep
explain the main difference between bronchi and bronchioles
bronchioles do not have cartilaginous support and are located at the beginning of the conducting airway (nasal cavity), whereas bronchi have cartilaginous support and are located at the end of the conducting airway, leading into the lungs
types of stimuli detected by thermoreceptors
detect changes in temperature
locate and describe structure and function of the heart wall layers
epicardium: external layer composed of two tissue layers; contains blood vessels, lymphatics, and vessels that supply the myocardium myocardium: middle layer; cardiac muscle tissue; responsible for the pumping action of the heart; muscle fibres are organized in bundles that swirl diagonally around the heart and generate the strong pumping action endocardium: inner layer; thin layer of endothelium overlying a thin layer of connective tissue; provides smooth lining for chambers of heart and covers valves of heart; minimizes surface friction as blood passes through the heart
structure of gastric glands within the gastric mucosa layer
epithelial cells extend down into the lamina propria, where they form columns of secretory cells called gastric glands. several gastric glands open into the bottom of narrow channels called gastric pits. secretions from several gastric glands flow into each gastric pit and then into the lumen of the stomach
define shock
failure of the cardiovascular system to deliver enough O2 and nutrients to meet cellular metabolic needs
steps of ovarian cycle
follicular phase (day 1-14): -under influence of FSH, several primordial follicles develop into primary follicles and then into secondary follicles -secondary follicles begin to secrete estrogens and inhibit -one follicle becomes dominant follicle; estrogens and inhibin secreted by DF will decrease secretion of FSH causing less well-developed follicles to stop growing and degenerate -dominant follicle becomes mature follicle and continues to enlarge until it is ready for ovulation and increases its production of estrogens ovulation (day 14): -rupture of mature follicle and release of secondary oocyte into pelvic cavity -secondary oocyte remains surrounded by its zona pellucida and corona radiata luteal phase (14-28): -mature follicle collapses and basement membrane between the granulosa cells and theca interna breaks down -theca interna cells mix with granulosa cells as they all become transformed into corpus luteum cells under influence of LH; LH stimulates corpus luteum to secrete progesterone, estrogens, relaxin, and inhibin -luteal cells also absorb blood clot -if secondary oocyte is not fertilized, corpus luteum has lifespan of two weeks and then becomes corpus albicans; progesterone, estrogens, and inhibin levels decrease, surprising GnRH, LH and FSH due to negative feedback; follicular growth resumes and new ovarian cycle begins -if secondary oocyte is fertilized and begins to divide, corpus luteum persists past its normal 2 week span; rescued from degeneration by human chorionic gonadotropin (hCG) which stimulates secretory activity of corpus luteum; presence of hCG in blood or urine = pregnancy
layers of the respiratory (alveolar-capillary) membrane
four primary components that make up exchange surface for diffusion across respiratory membrane: 1) a layer of type I and type II alveolar cells and associated alveolar macrophages that constitutes the alveolar wall 2) an epithelial basement membrane underlying the alveolar wall 3) a capillary basement membrane that is often fused to the epithelial basement membrane 4) the capillary endothelium
describe the nerve fascicle
groups of axons with their endoneurium
types of stimuli detected by proprioreceptors
information about the body position, muscle length and tension, and the position and movement of your joints
myelin sheath
lipid protein material that acts as an insulator of nerve cells and speeds up nerve conduction
describe the location of the endocrine pancreas
located in abdominal cavity behind the stomach
explain the difference between lung volume and lung capacity
lung volume: volume of air you inhale and exhale; tidal volume = volume of one breath (70% reaches respiratory zone; 30% remains in conducting zone); anatomic (respiratory) dead space = conducting airways with air that does not undergo respiratory exchange; inspiratory reserve volume (IRV) = additional inhaled air during deep breath (3100mL in males; 1900mL in females); expiratory reserve rate (ERV) = extra inhaled air during IRV; forced expiratory volume in 1 second (FEV1) = volume of air that can be exhaled from the lungs in 1 second with maximal effort following a maximal inhalation; residual volume (RV) = air remaining in lungs after ERV due to the sub atmospheric intrapleural pressure keeping alveoli slightly inflated and air remain gin in noncollapsible airways (~1200mL in males; 1100mL in females); minimal volume = air remaining after thoracic cavity is opened and intrapleural pressure rises to equal atmospheric pressure, forcing out some of the RV lung capacities: anatomical volume which you have the capacity for; inspiratory capacity = Vt+IRV; functional residual capacity (FRC) = RV+ERV; vital capacity (VC) = IRV+Vt+ERV; total lung capacity = VC+RV; minute ventilation = Vt•respiratory rate; alveolar ventilation (Va) = volume of air pre minute that actually reaches the respiratory zone
auto regulatory mechanisms that maintain GFR despite changes in blood pressure
myogenic mechanism: -occurs when stretching triggers contraction of smooth muscle cells in the walls of afferent arterioles -as BP rises, GFR also rises because renal blood flow increases, however elevated BP also stretches the walls of the afferent arterioles causing smooth muscle fibres in the walls to contract, narrowing the arterioles lumen. as a result, renal blood flow decreases, thus reducing GFR to its previous level -as BP drops, smooth muscle cells are stretched less and thus relax, causing the afferent arterioles to dilate, increasing renal blood flow, and increasing GFR. -normalizes renal blood flow and GFR within seconds after a change in blood pressure tubuloglomerular feedback: -when GFR is above normal due to elevated BP, filtered fluid flows more rapidly along renal tubules. as a result, the PCT and nephron loop have less time to reabsorb Na+, Cl-, and water. macula densa cells detect increased delivery of Na+, Cl-, and water and inhibit release of nitric oxide from cells in the juxtaglomerular apparatus. because NO causes vasodilation, afferent arterioles constrict when the level of NO declines. as a result, less blood flows into the glomerular capillaries, and GFR decreases. -when BP decreases, causing GFR to be lower than normal, the opposite sequence of events occurs, although to a lesser degree -operates more slowly than the myogenic mechanism
heart rate
number of heartbeats per minute
rima glottidis
opening between vocal folds
define summation
process by which the graded potentials add together
explain the function of cartilage in the trachea and bronchi
provide semirigid support to maintain patency so the walls of the trachea and bronchi do not collapse
explain the difference between the pulmonary and bronchial circulations
pulmonary circulation -deoxygenated blood passes through the pulmonary trunk which divides into the left and right pulmonary arteries that enter the left and right lungs; only arteries in body that carry deoxygenated blood -pulmonary veins return oxygenated blood to heart bronchial circulation -bronchial arteries carry oxygenated blood to lungs -bood enters pulmonary capillaries; site of gas exchange -blood enter bronchial veins
superior vena cava
receives blood from the head and arms and chest and empties into the right atrium of the heart
blood flow through kidneys
renal artery - segmental arteries (supply different segments of kidneys) - interlobar arteries (pass between renal lobes) - arcuate arteries (between renal medulla and cortex) - cortical radiate arteries (enter renal cortex) - afferent arterioles (each nephron receives one AA) - glomerular capillaries (tangled, ball-shaped capillary network) - efferent arterioles (carry blood out of glomerulus) - peritubular capillaries (surround tubular parts of nephron in cortex) - peritubular venules - cortical radiate veins (also receive blood from vasa recta) - arcuate veins - interlobar veins - renal vein
components of the kidney nephron
renal corpuscle and renal tubule
types of stimuli detected by nocireceptors
respond to painful stimuli resulting from physical or chemical damage to tissue
cauda equina
roots of lower spinal nerves
function of secretions of duodenal glands in submucosal layer
secrete alkaline mucus that helps neutralize gastric acid in the chyme
function of seminal vesicles
secretes fructose and most of seminal fluid
function of prostate gland
secretes watery alkaline fluid to neutralize urine
longitudinal fissure
separates the cerebrum into right and left halves called cerebral hemispheres
central sulcus
separates the frontal lobe from the parietal lobe
interventricular septum
separates the right and left ventricles
function of epididymis
site of sperm development and storage
pulmonary venule
small vein containing oxygenated blood being carried away from the alveoli and towards the heart
chyme
soupy liquid mixture of gastric contents and gastric juice
compare spatial and temporal summation
spatial summation: summation of postsynaptic potentials in response to stimuli that occur at different locations in the membrane of a postsynaptic cell at the same time temporal summation: summation of postsynaptic potentials in response to stimuli that occur at the same location in the membrane of the postsynaptic cell but at different times
describe how sympathetic and parasympathetic activation affect heart rate and stroke volume
sympathetic activation: impulses in cardiac accelerator nerves triggers the release of norepinephrine causing 1) the SA and AV node fibres speed the rate of spontaneous depolarization thus increasing heart rate, and 2) enhances Ca++ entry through voltage-gated slow Ca++ channels in contractile fibres throughout the atria and ventricles increasing contractility; with a moderate increase in HR, SV will not decline; with higher HR, SV is lower than at rest parasympathetic activation: impulses reach heart through vagus (X) nerve; releases acetylcholine which decreases HR by slowing the rate of spontaneous depolarization in autorhythmic fibres; few vagal fibres innervate ventricular muscle so there is little effect on SV
aorta
the large trunk artery that carries blood from the left ventricle of the heart to branch arteries
functional significance of the additional muscle layer in the stomach wall
the oblique layer aids in digestion by grinding the food together with the digestive juices, creatine chyme
define reflex arc
the pathway followed by nerve impulses that produce a reflex
function of vas deferens
tube for sperm development, storage, and transport
function of ejaculatory duct
tube for transporting sperm and glandular secretions
function of urethra
tube that carries urine and semen to be excreted
roots
two bundles of axons
auditory tube openings
two openings in the oropharynx
theca cells
under LH stimulation, produce androgen of which small percentage is released to the circulation and the rest enters granulosa cells
define transport maximum
upper limit of a transporter on how fast it can work (mg/min)
