Anatomy & Physiology Final Exam

saddle joint

In a synovial joint called a saddle joint or sellar joint, the articular surface of one bone is saddle-shaped, and the articular surface of the other bone fits into the "saddle" as a sitting rider would sit. The movements at this joint are the same as those at a condyloid joint: biaxial (flexion-extension and abduction-adduction) -An example of this joint is the carpometacarpal joint between the trapezium of the carpus and metacarpal of the thumb.

synovial fluid

The synovial membrane secretes _____________, a viscous, clear or pale yellow fluid named for its similarity in appearance and consistency to uncooked egg white. Synovial fluid consists of hyaluronic acid secreted by fibroblast-like cells in the synovial membrane and interstitial fluid filtered from blood plasma. It forms a thin film over the surfaces within the articular capsule. Its functions include reducing friction by lubricating the joint, absorbing shocks, and supplying oxygen and nutrients to and removing carbon dioxide and metabolic wastes from the chondrocytes within articular cartilage. This fluid also contains phagocytic cells that remove microbes and the debris that results from normal wear and tear in the joint.

loss of water, bacterial infection, reduced circulation, decreased production of urine, diminished immune responses

The systemic effects of a burn may include:

myoglobin

This protein, found only in muscle, binds oxygen molecules that diffuse into muscle fibers from interstitial fluid. It releases oxygen when it is needed by the mitochondria for ATP production. The mitochondria lie in rows throughout the muscle fiber, strategically close to the contractile muscle proteins that use ATP during contraction so that ATP can be produced quickly as needed

RNA polymerase

enzyme used to unzip DNA so mRNA can copy

diaphysis

the bone's shaft or body—the long, cylindrical, main portion of the long bone.

introns

the non coding segments of DNA that need to be spliced out

bulk phase endocytosis

"Cell drinking"; movement of extracellular fluid into a cell by infolding of plasma membrane to form a vesicle. Solutes in extracellular fluid are transported in this way.

phagocytosis

"Cell eating"; movement of a solid particle into a cell after pseudopods engulf it to form a phagosome. Bacteria, viruses, and aged or dead cells are transported into the cell this way.

fat

A ____ is a triglyceride that is a solid at room temperature. The fatty acids of a _(same)_ are mostly saturated. Because these saturated fatty acids lack double bonds in their hydrocarbon chains, they can closely pack together and solidify at room temperature.

reflex

A _________ is a fast, involuntary, unplanned sequence of actions that occurs in response to a particular stimulus. -Some are inborn, such as pulling your hand away from a hot surface before you even feel that it is hot

membrane

A ___________ is a sheet-like structure in the body. THere are three kinds in the body, connective and epithelial, as well as cutaneous.

disaccharide

A _____________ is a molecule formed from the combination of two monosaccharides by dehydration synthesis. For example, molecules of the monosaccharides glucose and fructose combine to form a molecule of sucrose (table sugar).

control center

A ______________ in the body, for example, the brain, sets the range of values within which a controlled condition should be maintained (set point), evaluates the input it receives from receptors, and generates output commands when they are needed. Output from the control center typically occurs as nerve impulses, or hormones or other chemical signals. This pathway is called an efferent pathway.

somatic cell

A ______________ is any cell of the body other than a germ cell.

10, 25

According to the American Burn Association's classification of burn injury, a major burn includes third-degree burns over __% of body surface area; or second-degree burns over __% of body surface area; or any third-degree burns on the face, hands, feet, or perineum.

primary active transport

Active process in which a substance moves across the membrane against its concentration gradient by pumps (carriers) that use energy supplied by hydrolysis of ATP. many cations are transported this way

tight junctions, adherens junctions, desmosomes, hemidesmosomes, gap junctions

Cell junctions are contact points between the plasma membranes of tissue cells. What are the five different ones?

nicotinic receptors, muscarinic receptors

Cholinergic neurons release the neurotransmitter acetylcholine (ACh). In the ANS, the cholinergic neurons include (1) all sympathetic and parasympathetic preganglionic neurons, (2) sympathetic postganglionic neurons that innervate most sweat glands, and (3) all parasympathetic postganglionic neurons The two types of cholinergic receptors, both of which bind ACh, are _______________ and ________________. -The former are present in the cell bodies and dendrites of both sympathetic and parasympathetic postganglionic neurons, plasma membranes of chromaffin cells, and in motor end plate of NMJ. - The latter are present in the plasma membranes of all effectors (smooth muscle, cardiac muscle, and glands) innervated by parasympathetic postganglionic axons. In addition, most sweat glands receive their innervation from cholinergic sympathetic postganglionic neurons and possess muscarinic receptors.

ribosome

Composed of two subunits containing ribosomal RNA and proteins; may be free in cytosol or attached to rough ER. Their function is protein synthesis

golgi apparatus

Consists of 3-20 flattened membranous sacs called cisternae; structurally and functionally divided into entry (cis) face, medial cisternae, and exit (trans) face. Entry (cis) face accepts proteins from rough ER; medial cisternae form glycoproteins, glycolipids, and lipoproteins; exit (trans) face modifies molecules further, then sorts and packages them for transport to their destinations.

anaphase

During the _____________ phase of mitosis, the centromeres split, separating the two members of each chromatid pair, which move toward opposite poles of the cell. Once separated, the chromatids are termed chromosomes. As the chromosomes are pulled by the microtubules of the mitotic spindle during anaphase, they appear V-shaped because the centromeres lead the way, dragging the trailing arms of the chromosomes toward the pole.

telophase

During the final stage of mitosis, ____________, which begins after chromosomal movement stops, the identical sets of chromosomes, now at opposite poles of the cell, uncoil and revert to the threadlike chromatin form. A nuclear envelope forms around each chromatin mass, nucleoli reappear in the identical nuclei, and the mitotic spindle breaks up.

nitrogenous base, pentose sugar, phosphate group

Each nucleotide of DNA consists of three parts:

epidermal wound healing

Even though the central portion of an epidermal wound may extend to the dermis, the edges of the wound usually involve only slight damage to superficial epidermal cells. Common types of ___________________ include abrasions, in which a portion of skin has been scraped away, and minor burns. In response to an epidermal injury, basal cells of the epidermis surrounding the wound break contact with the basement membrane. The cells then enlarge and migrate across the wound. The cells appear to migrate as a sheet until advancing cells from opposite sides of the wound meet. When epidermal cells encounter one another, they stop migrating due to a cellular response called contact inhibition. Migration of the epidermal cells stops completely when each is finally in contact with other epidermal cells on all sides. As the basal epidermal cells migrate, a hormone called epidermal growth factor stimulates basal stem cells to divide and replace the ones that have moved into the wound. The relocated basal epidermal cells divide to build new strata, thus thickening the new epidermis.

hypothalamus

Functions of the ________________: 1. control of the ANS 2. production of hormones 3. regulation of emotional and behavioral patterns 4. regulation of eating and drinking 5. control of body temperature 6. regulation of circadian rhythms and states of consciousness

pivot joints

In synovial joints called ______________, or trochoid joints, the rounded or pointed surface of one bone articulates with a ring formed partly by another bone and partly by a ligament. -such a joint is uniaxial because it allows rotation only around its own longitudinal axis. -examples include the atlanto-axial joint, in which the atlas rotates around the axis and permits the head to turn from side to side as when you shake your head "no", and the radioulnar joints that enable the palms to turn anteriorly and posteriorly as the head of the radius pivots around its long axis in the radial notch of the ulna.

pivot joints

In these synovial joints (axis of rotation in same axis as long axis of bone), rotation around longitudinal axis of bone only is permitted. Examples include the first cervical vertebra- the atlas around odontoid process of second cervical vertebra; proximal and distal articulations of the radius and ulna. These joints are also uniaxial, and they allow only one axis of movement.

condyloid joints

In this type of synovial joint, one articular surface is slightly concave, and the other is slightly convex, permitting movement in two planes. Examples include the the radius and carpals, occipital condyles on atlas, and metacarpal-phalangeal joints. These joints are biaxial, and thus allow for two axes of rotation at the joint

accessory ligaments

Many synovial joints also contain _____________ called extracapsular ligaments and intracapsular ligaments. Extracapsular ligaments lie outside the articular capsule. Examples are the fibular and tibial collateral ligaments of the knee joint. Intracapsular ligaments occur within the articular capsule but are excluded from the synovial cavity by folds of the synovial membrane. Examples are the anterior and posterior cruciate ligaments of the knee joint.

endoplasmic reticulum

Membranous network of flattened sacs or tubules. Rough ER is covered by ribosomes and is attached to the nuclear envelope; smooth ER lacks ribosomes. Functions for Rough ER include synthesizing glycoproteins and phospholipids that are transferred to cellular organelles, inserted into plasma membrane, or secreted during exocytosis; smooth ER: synthesizes fatty acids and steroids, inactivates or detoxifies drugs, removes phosphate group from glucose-6-phosphate, and stores and releases calcium ions in muscle cells.

prophase, metaphase, anaphase, telophase

Mitosis, as noted earlier, is the distribution of two sets of chromosomes into two separate nuclei. The process results in the exact partitioning of genetic information. For convenience, biologists divide the process into four stages: __________, ___________, ___________, ____________. However, mitosis is a continuous process; one stage merges seamlessly into the next.

amphipathic

Molecules that have both polar and nonpolar parts are said to be ____________.

cilia, flagella

Motile cell surface projections that contain 20 microtubules and a basal body.

transcytosis

Movement of a substance through a cell as a result of endocytosis on one side and exocytosis on the opposite side. Substances, such as antibodies, across endothelial cells. This is a common route for substances to pass between blood plasma and interstitial fluid are transported this way.

contractile proteins, regulatory proteins, structural proteins

Myofibrils are built from three kinds of proteins:

Z discs

Narrow, plate-shaped regions of dense protein material called __________ separate one sarcomere from the next.

osmosis

Passive movement of water molecules across a selectively permeable membrane from an area of higher to lower water concentration until equilibrium is reached.

polyunsaturated fats

Polyunsaturated fats contain triglycerides that mostly consist of polyunsaturated fatty acids. Corn oil, safflower oil, sunflower oil, soybean oil, and fatty fish (salmon, tuna, and mackerel) contain a high percentage of this. They are known to decrease risk of heart disease.

primary structure, secondary structure, tertiary structure, quaternary structure

Proteins exhibit four levels of structural organization: 1. ________________ is the unique sequence of amino acids that are linked by covalent peptide bonds to form a polypeptide chain. 2. The _______________ of a protein is the repeated twisting or folding of neighboring amino acids in the polypeptide chain. 3. _______________ refers to the three-dimensional shape of a polypeptide chain. Each protein has a unique shape. 4. The arrangement of the individual polypeptide chains relative to one another is the _______________.

organelle

Specialized structures with characteristic shapes within the cell. Each of these structures has a specific function

stratum spinosum

Superficial to the stratum basale is the ________________. This stratum mainly consists of numerous keratinocytes arranged in 8-10 layers. Cells in the more superficial layers become somewhat flattened. The keratinocytes in this layer, which are produced by the stem cells in the basal layer, have the same organelles as cells of the stratum basale and some retain their ability to divide. The keratinocytes of this layer produce coarser bundles of keratin in intermediate filaments than those of the basal layer. Although they are rounded and larger in living tissue, cells of this skin layer are shrink and pull apart when prepared for microscopic examination so that they appear to be covered with thorn-like spines (thus, the name). -At each spinelike projection, bundles of keratin intermediate filaments insert into desmosomes, which tightly join the cells to one another. This arrangement provides both strength and flexibility to the skin. Langerhans cells and projections of melanocytes are also present in the __(same)__.

hypodermis

The ____________ is the layer that separates muscle from skin. It is vascularized

articular cartilage

The ________________ is a thin layer of hyaline cartilage covering the part of the epiphysis where the bone forms an articulation (joint) with another bone. It reduces friction and absorbs shock at freely movable joints. Because it lacks a perichondrium and lacks blood vessels, repair of damage is limited.

central nervous system

The ______________________ consists of the brain and spinal cord. -This processes many different kinds of incoming sensory information. It is also the source of thoughts, emotions, and memories. -Most signals that stimulate muscles to contract and glands to secrete originate in this.

sarcoplasm

The cytoplasm of a muscle fiber. This includes a substantial amount of glycogen, which is a large molecule composed of many glucose molecules. This also includes myoglobin

transcription

The process of making DNA into mRNA

rhodopsin

The single type of photopigment in rods is ___________.

homologous chromosomes

The two chromosomes that make up each pair are called __________________.

gliding joints

These synovial joints are found between articular processes of vertebrae and between most carpal and tarsal bones.

messenger RNA

This type of RNA directs the synthesis of a protein

epimysium, perimysium, endomysium

Three layers of connective tissue extend from the fascia to protect and strengthen skeletal muscle:

messenger RNA, ribosomal RNA, Transfer RNA

Three types of RNA are made from the DNA template:

glycogen

Unlike simple sugars, polysaccharides usually are insoluble in water and do not taste sweet. The main polysaccharide in the human body is __________, which is made entirely of glucose monomers linked to one another in branching chains.

proteasome

Vesicle containing oxidases (oxidative enzymes) and catalase (decomposes hydrogen peroxide); new peroxisomes bud from preexisting ones. Oxidizes amino acids and fatty acids; detoxifies harmful substances, such as hydrogen peroxide and associated free radicals. It degrades unneeded, damaged, or faulty proteins by cutting them into small peptides.

lysosome

Vesicle formed from Golgi complex; contains digestive enzymes. Fuses with and digests contents of endosomes, pinocytic vesicles, and phagosomes and transports final products of digestion into cytosol; digests worn-out organelles (autophagy), entire cells (autolysis), and extracellular materials.

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

What are the layers of thick skin, starting at the dermis?

stratum basale, stratum spinosum, stratum granulosum, stratum corneum

What are the layers of thin skin, starting at the dermis?

gliding joints, hinge joints, pivot joints, condyloid joints, saddle joints, ball and socket joints

What are the six types of synovial joints?

development of the cartilage model, growth of the cartilage model, development of primary ossification center, development of the medullary cavity, development of secondary ossification centers, formation of articular cartilage and epiphyseal growth plate

What are the steps of endochondral ossification?

development of ossification center, calcification, formation of trabeculae, development of periosteum

What are the steps of intramembranous ossification?

receptor, control center, effector

What are the three components of a feedback system?

transcription, translation

What are the two main steps of protein synthesis?

transcription

Which occurs first in protein synthesis, transcription or translation?

creatine phosphate, creatine,

While muscle fibers are relaxed, they produce more ATP than they need for resting metabolism. Most of the excess ATP is used to synthesize ________________, an energy-rich molecule that is found in muscle fibers. The enzyme creatine kinase (CK) catalyzes the transfer of one of the high-energy phosphate groups from ATP to creatine, forming creatine phosphate and ADP. ___________ is a small, amino acid-like molecule that is synthesized in the liver, kidneys, and pancreas and then transported to muscle fibers. -When contraction begins and the ADP level starts to rise, CK catalyzes the transfer of a high-energy phosphate group from creatine phosphate back to ADP. This direct phosphorylation reaction quickly generates new ATP molecules. -Since the formation of ATP from creatine phosphate occurs very rapidly, creatine phosphate is the first source of energy when muscle contraction begins. The other energy-generating mechanisms in a muscle fiber (the pathways of anaerobic and aerobic cellular respiration) take a relatively longer period of time to produce ATP compared to creatine phosphate. -Together, stores of creatine phosphate and ATP provide enough energy for muscles to contract maximally for about 15 seconds.

hemidesmosomes

__________________ resemble desmosomes, but they do not link adjacent cells. The name arises from the fact that they look like half of a desmosome. However, the transmembrane glycoproteins in these cell junctions are integrins rather than cadherins. On the inside of the plasma membrane, integrins attach to intermediate filaments made of the protein keratin. On the outside of the plasma membrane, the integrins attach to the protein laminin, which is present in the basement membrane (discussed shortly). Thus, these junctions anchor cells not to each other but to the basement membrane.

adenosine triphosphate

____________________ is the "energy currency" of living systems

fascia

_________is a dense sheet or broad band of irregular connective tissue that lines the body wall and limbs and supports and surrounds muscles and other organs of the body. - It also holds muscles of similar functions together.

peptide bonds

amino acids are joined together by what bonds?

monosaccharides

simple sugars are the monomers of carbohydrates. They are known as?

transcription

takes place in the nucleus (transcription or translation)?

metaphyses

the regions between the diaphysis and the epiphyses. In a growing bone, each one contains an epiphyseal (growth) plate, a layer of hyaline cartilage that allows the diaphysis of the bone to grow in length. When a bone ceases to grow in length at about ages 18-21, the cartilage in the epiphyseal plate is replaced by bone; the resulting bony structure is known as the epiphyseal line.

sex chromosomes

x and y chromosomes are called

glycoprotein, opsin, retinal

All photopigments associated with vision contain two parts: a ___________ known as _________ and a derivative of vitamin A called _________.

oil

An ______ is a triglyceride that is a liquid at room temperature. The fatty acids of an _(same)_ are mostly unsaturated.

effector

An ___________ is a body structure that receives output from the control center and produces a response or effect that changes the controlled condition. Nearly every organ or tissue in the body can behave as this. When your body temperature drops sharply, your brain (control center) sends nerve impulses (output) to your skeletal muscles (effectors). The result is shivering, which generates heat and raises your body temperature.

agonist

An _____________ is a substance that binds to and activates a receptor, in the process mimicking the effect of a natural neurotransmitter or hormone

antagonist

An ______________ is a substance that binds to and blocks a receptor, thereby preventing a natural neurotransmitter or hormone from exerting its effect.

autonomic efferent pathways

-sensory input is from the interoreceptors. -The control of motor output is from the hypothalamus, limbic system, brain stem, and spinal cord; limited control from cerebral cortex. -motor neuron pathway is usually two-neuron pathway: Preganglionic neurons extending from CNS synapse with postganglionic neurons in autonomic ganglion, and postganglionic neurons extending from ganglion synapse with visceral effector. Alternatively, preganglionic neurons may extend from CNS to synapse with chromaffin cells of adrenal medullae. -neurotransmitters and hormones: All sympathetic and parasympathetic preganglionic neurons release ACh. Most sympathetic postganglionic neurons release NE; those to most sweat glands release ACh. All parasympathetic postganglionic neurons release ACh. Chromaffin cells of adrenal medullae release epinephrine and norepinephrine. -effectors: Smooth muscle, cardiac muscle, and glands. responses: Contraction or relaxation of smooth muscle; increased or decreased rate and force of contraction of cardiac muscle; increased or decreased secretions of glands.

joint

A _________ is a place where two bones come in contact with each other; a bone is any continuous

receptor

A __________ is a body structure that monitors changes in a controlled condition and sends input to a control center. This pathway is called an afferent pathway.

synapse, synaptic cleft, neurotransmitter

A ___________ is a region where communication occurs between two neurons, or between a neuron and a target cell—in this case, between a somatic motor neuron and a muscle fiber. At most synapses a small gap, called the ______________, separates the two cells. Because the cells do not physically touch, the action potential cannot "jump the gap" from one cell to another. Instead, the first cell communicates with the second by releasing a chemical called a ________________.

stretch reflex

A _____________ causes contraction of a skeletal muscle (the effector) in response to stretching of the muscle. This type of reflex occurs via a monosynaptic reflex arc. The reflex can occur by activation of a single sensory neuron that forms one synapse in the CNS with a single motor neuron. -These reflexes can be elicited by tapping on tendons attached to muscles at the elbow, wrist, knee, and ankle joints.

germ cell

A _____________ is a gamete (sperm or oocyte) or any precursor cell destined to become a gamete.

negative feedback system,

A ______________ reverses a change in a controlled condition, to bring it back to a controlled state. Consider the regulation of blood pressure. Blood pressure (BP) is the force exerted by blood as it presses against the walls of blood vessels. When the heart beats faster or harder, BP increases. If some internal or external stimulus causes blood pressure (controlled condition) to rise, Baroreceptors (the receptors), pressure-sensitive nerve cells located in the walls of certain blood vessels, detect the higher pressure. The baroreceptors send nerve impulses (input) to the brain (control center), which interprets the impulses and responds by sending nerve impulses (output) to the heart and blood vessels (the effectors). Heart rate decreases and blood vessels dilate (widen), which cause BP to decrease (response). This sequence of events quickly returns the controlled condition—blood pressure—to normal, and homeostasis is restored. Notice that the activity of the effector causes BP to drop, a result that negates the original stimulus (an increase in BP).

first degree burn

A _______________ involves only the epidermis. It is characterized by mild pain and erythema (redness) but no blisters. Skin functions remain intact. Immediate flushing with cold water may lessen the pain and damage caused. Generally, healing of this type of burn will occur in 3 to 6 days and may be accompanied by flaking or peeling. One example is mild sunburn.

positive feedback system

A _______________ tends to strengthen or reinforce a change in one of the body's controlled conditions. In a positive feedback system, the response affects the controlled condition differently than in a negative feedback system. The control center still provides commands to an effector, but this time the effector produces a physiological response that adds to or reinforces the initial change in the controlled condition. Normal childbirth provides a good example. The first contractions of labor (stimulus) push part of the fetus into the cervix, the lowest part of the uterus, which opens into the vagina. Stretch-sensitive nerve cells (receptors) monitor the amount of stretching of the cervix (controlled condition). As stretching increases, they send more nerve impulses (input) to the brain (control center), which in turn re- leases the hormone oxytocin (output) into the blood. Oxytocin causes muscles in the wall of the uterus (effector) to contract even more forcefully. The contractions push the fetus farther down the uterus, which stretches the cervix even more. The cycle of stretching, hormone release, and ever-stronger contractions is interrupted only by the birth of the baby. Then, stretching of the cervix ceases and oxytocin is no longer released.

second degree burn

A _________________ destroys the epidermis and part of the dermis. Some skin functions are lost. In this type of burn, redness, blister formation, edema, and pain result. In a blister the epidermis separates from the dermis due to the accumulation of tissue fluid between them. Associated structures, such as hair follicles, sebaceous glands, and sweat glands, usually are not injured. If there is no infection, these burns heal without skin grafting in about 3 to 4 weeks, but scarring may result.

third degree burn

A _________________ or full-thickness burn destroys the epidermis, dermis, and subcutaneous layer. Most skin functions are lost. Such burns vary in appearance from marble-white to mahogany colored to charred, dry wounds. There is marked edema, and the burned region is numb because sensory nerve endings have been destroyed. Regeneration occurs slowly, and much granulation tissue forms before being covered by epithelium. Skin grafting may be required to promote healing and to minimize scarring.

articular capsule, fibrous, synovial

A sleevelike ______________ surrounds a synovial joint, encloses the synovial cavity, and unites the articulating bones. It is composed of two layers: The outer ___________ membrane, and the inner ____________ membrane

triad

A transverse tubule and the two terminal cisterns on either side of it form a _______.

glycerol, fatty acid

A triglyceride consists of two types of building blocks, a single ___________ molecule and three ___________ molecules.

release of acetylcholine, activation of acetylcholine receptors, production of muscle action potential, termination of acetylcholine activity

A nerve impulse (nerve action potential) elicits a muscle action potential in the following way:

excitatory postsynaptic potential

A neurotransmitter that causes depolarization of the postsynaptic membrane is excitatory because it brings the membrane closer to threshold. A depolarizing postsynaptic potential is called an _________________. -Although a single one normally does not initiate a nerve impulse, the postsynaptic cell does become more excitable.

inhibitory postsynaptic potential

A neurotransmitter that causes hyperpolarization of the postsynaptic membrane is inhibitory -During hyperpolarization, generation of an action potential is more difficult than usual because the membrane potential becomes inside more negative and thus even farther from threshold than in its resting state. - A hyperpolarizing postsynaptic potential is termed an __________________.

nucleotides

A nucleic acid is a chain of repeating monomers called ___________.

saturated fat

A fat (triglyceride) that mainly consists of saturated fatty acids is called a _____________. Although these occur mostly in meats (especially red meats) and non-skim dairy products (whole milk, cheese, and butter), they are also found in a few plant products, such as cocoa butter, palm oil, and coconut oil. Diets that contain large amounts of _____(same)_____ are associated with disorders such as heart disease and colorectal cancer.

sarcoplasmic reticulum

A fluid-filled system of membranous sacs called the ____________, encircles each myofibril. Dilated end sacs of the sarcoplasmic reticulum called terminal cisterns, butt against the T tubule from both sides. In a relaxed muscle fiber, this structure stores calcium ions (Ca2+). Release of Ca2+ from the terminal cisterns of the sarcoplasmic reticulum triggers muscle contraction.

feedback system

A group of receptors and effectors communicating with their control center forms a _____________ that can regulate a controlled condition in the body's internal environment. In a feedback system, the response of the system "feeds back" information to change the controlled condition in some way, either negating it (negative feedback) or enhancing it (positive feedback).

active transport

Active process in which a cell expends energy to move a substance across the membrane against its concentration gradient by transmembrane proteins that function as carriers. Polar or charged solutes are transferred this way.

transport in vesicles

Active process in which substances move into or out of cells in vesicles that bud from plasma membrane; requires energy supplied by ATP.

excitation contraction coupling

As a muscle action potential propagates along the sarcolemma and into the T tubules, it causes Ca2+ release channels in the SR membrane to open. When these channels open, Ca2+ flows out of the SR into the sarcoplasm around the thick and thin filaments. As a result, the Ca2+ concentration in the sarcoplasm rises tenfold or more. The released calcium ions combine with troponin, causing it to change shape. This conformational change moves tropomyosin away from the myosin-binding sites on actin. Once these binding sites are free, myosin heads bind to them to form cross-bridges, and the contraction cycle begins. The events just described are referred to collectively as ___________________.

myofibrils

At high magnification, the sarcoplasm appears stuffed with little threads. These small structures are the myofibrils, the contractile organelles of skeletal muscle. These threadlike structures are about 2 mu m in diameter and extend the entire length of a muscle fiber. Their prominent striations make the entire skeletal muscle fiber appear striped (striated).

articular fat pads

At many synovial joints the synovial membrane includes accumulations of adipose tissue, called ________________. An example is the infrapatellar fat pad in the knee

axon terminal, synaptic end bulbs, synaptic vesicles, acetylcholine

At the neuromuscular junction, the end of the motor neuron, called the ______________, divides into a cluster of ________________. Suspended in the cytosol within each __(same as blank 2)__ are hundreds of membrane-enclosed sacs called _______________. Inside each of theses sacs are thousands of molecules of _______________.

diploid cells

Because somatic cells contain two sets of chromosomes, they are called ___________.

nucleus

Consists of a nuclear envelope with pores, nucleoli, and chromosomes, which exist as a tangled mass of chromatin in interphase cells. Nuclear pores control the movement of substances between the nucleus and cytoplasm, nucleoli produce ribosomes, and chromosomes consist of genes that control cellular structure and direct cellular functions.

secondary active transport

Coupled active transport of two substances across the membrane using energy supplied by a Na+ or H+ concentration gradient maintained by primary active transport pumps. Antiporters move Na+ (or H+) and another substance in opposite directions across the membrane; symporters move Na+ (or H+) and another substance in the same direction across the membrane.

interphase

During _____________, the cell replicates its DNA through a process that will be described shortly. It also produces additional organelles and cytosolic components in anticipation of cell division. It is a phase of high metabolic activity; it is during this time that the cell does most of its growing. It consists of three phases: G1, S, and G2. -The G1 phase is the interval between the mitotic phase and the S phase. During G1, the cell is metabolically active; it replicates most of its organelles and cytosolic components but not its DNA. Replication of centrosomes also begins in the G1 phase. Virtually all the cellular activities described in this chapter happen during G1. For a cell with a total cell cycle time of 24 hours, G1 lasts 8 to 10 hours. However, the duration of this phase is quite variable. It is very short in many embryonic cells or cancer cells. Cells that remain in G1 for a very long time, perhaps destined never to divide again, are said to be in the G0 phase. Most nerve cells are in the G0 phase. Once a cell enters the S phase, however, it is com- mitted to go through the rest of the cell cycle. -The S phase, the interval between G1 and G2, lasts about 8 hours. During the S phase, DNA replication occurs. As a result of DNA replication, the two identical cells formed during cell division later in the cell cycle will have the same genetic material. -The G2 phase is the interval between the S phase and the mitotic phase. It lasts 4 to 6 hours. During G2, cell growth continues, enzymes and other proteins are synthesized in preparation for cell division, and replication of centrosomes is completed. When DNA replicates during the S phase, its helical structure partially uncoils, and the two strands separate at the points where hydrogen bonds connect base pairs. Each exposed base of the old DNA strand then pairs with the complementary base of a newly synthesized nucleotide. A new DNA strand takes shape as chemical bonds form between neighboring nucleotides. The un- coiling and complementary base pairing continues until each of the two original DNA strands is joined with a newly formed complementary DNA strand. The original DNA molecule has become two identical DNA molecules.

transcription

During _______________, which occurs in the nucleus, the genetic information represented by the sequence of base triplets in DNA serves as a template for copying the information into a complementary sequence of codons.

aerobic cellular respiration

During periods of rest or light to moderate exercise, a sufficient amount of oxygen is available to skeletal muscle fibers. In such cases, ATP used for muscular activity is produced from a series of oxygen-requiring reactions called _________________. -During this process, pyruvic acid enters the mitochondria, where it is completely oxidized in reactions that generate ATP, carbon dioxide, water, and heat. -Although aerobic cellular respiration is slower than glycolysis, it yields much more ATP. One molecule of glucose yields about 36 molecules of ATP via aerobic cellular respiration, but yields only 2 molecules of ATP via anaerobic glycolysis.

metaphase

During the ____________ phase of mitosis, the microtubules of the mitotic spindle align the centromeres of the chromatid pairs at the exact center of the mitotic spindle. This midpoint region is called the __(same as above)__ plate.

prophase

During the early part of this phase of mitosis, the chromatin fibers condense and shorten into chromosomes that are visible under the light microscope. The condensation process may prevent entangling of the long DNA strands as they move during mitosis. Because longitudinal DNA replication took place during the S phase of interphase, each prophase chromosome consists of a pair of identical strands called chromatids. A constricted region called a centromere holds the chromatid pair together. At the outside of each centromere is a protein complex known as the kinetochore. Later in prophase, tubulins in the pericentriolar material of the centrosomes start to form the mitotic spindle, a football-shaped assembly of microtubules that attach to the kinetochore. As the microtubules lengthen, they push the centrosomes to the poles (ends) of the cell so that the spindle extends from pole to pole. The mitotic spindle is responsible for the separation of chromatids to opposite poles of the cell. Then, the nucleolus disappears and the nuclear envelope breaks down.

muscle fibers

Each of your skeletal muscles is a separate organ composed of hundreds to thousands of cells, which are called ___________ because of their elongated shapes.

articular discs, menisci

Inside some synovial joints, such as the knee, crescent-shaped pads of fibrocartilage lie between the articular surfaces of the bones and are attached to the fibrous capsule. These pads are called _____________, or ___________

calsequestrin

Inside the SR, molecules of a calcium-binding protein, appropriately called _______________, bind to the Ca2+, enabling even more Ca2+ to be sequestered or stored within the SR. As a result, the concentration of Ca2+ is 10,000 times higher in the SR than in the cytosol in a relaxed muscle fiber.

receptor mediated endocytosis

Ligand-receptor complexes trigger infolding of a clathrin-coated pit that forms a vesicle containing ligands. Ligands: transferrin, low-density lipoproteins (LDLs), some vitamins, certain hormones, and antibodies are transferred this way.

desmosomes

Like adherens junctions, _____________ contain plaque and have transmembrane glycoproteins (cadherins) that extend into the intercellular space between adjacent cell membranes and attach cells to one another. However, unlike adherens junctions, the plaque of these junctions does not attach to microfilaments. Instead, a plaque attaches to elements of the cytoskeleton known as intermediate filaments, which consist of the protein keratin. The intermediate filaments extend from these junctions on one side of the cell across the cytosol to other of these on the opposite side of the cell. This structural arrangement contributes to the stability of the cells and tissue. These spot-weld-like junctions are common among the cells that make up the epidermis (the outermost layer of the skin) and among cardiac muscle cells in the heart. These cell junctions prevent epidermal cells from separating under tension and cardiac muscle cells from pulling apart during contraction.

bone remodeling

Like skin, bone forms before birth but continually renews itself thereafter. ________________ is the ongoing replacement of old bone tissue by new bone tissue. It involves bone resorption, the removal of minerals and collagen fibers from bone by osteoclasts, and bone deposition, the addition of minerals and collagen fibers to bone by osteoblasts. Thus, bone resorption results in the destruction of bone extracellular matrix, while bone deposition results in the formation of bone extracellular matrix. -This process also takes place at different rates in different regions of the body. The distal portion of the femur is replaced about every four months. By contrast, bone in certain areas of the shaft of the femur will not be replaced completely during an individual's life. Even after bones have reached their adult shapes and sizes, old bone is continually destroyed and new bone is formed in its place. - This process also removes injured bone, replacing it with new bone tissue. Remodeling may be triggered by factors such as exercise, sedentary lifestyle, and changes in diet. - This process has several other benefits. Since the strength of bone is related to the degree to which it is stressed, if newly formed bone is subjected to heavy loads, it will grow thicker and therefore be stronger than the old bone. Also, the shape of a bone can be altered for proper support based on the stress patterns experienced during the remodeling process. Finally, new bone is more resistant to fracture than old bone.

diffusion

Movement of molecules or ions down a concentration gradient due to their kinetic energy until they reach equilibrium.

active

Movement of substances against a concentration gradient; requires cellular energy in the form of ATP. These are called ___________ processes.

passive

Movement of substances down a concentration gradient until equilibrium is reached; do not require cellular energy in the form of ATP. These are called ___________ processes.

endocytosis

Movement of substances into a cell in vesicles.

exocytosis

Movement of substances out of a cell in secretory vesicles that fuse with the plasma membrane and release their contents into the extracellular fluid. Neurotransmitters, hormones, and digestive enzymes are transported this way.

glucose

If a molecule of __________ is completely broken down, the chemical energy in its bonds can be used to produce as many as 38 molecules of ATP. The energy transferred to the ATP molecules is then used to drive endergonic reactions needed to build body structures, such as muscles and bones.

denaturation

If a protein encounters an altered environment, it may unravel and lose its characteristic shape (secondary, tertiary, and quaternary structure). This process is called _____________.

rule of nines

If the burn area of a victim exceeds more than 70%, more than half the victims die. A quick means for estimating the surface area affected by a burn in an adult: 1. Count 9% if both the anterior and posterior surfaces of the head and neck are affected. 2. Count 9% for both the anterior and posterior surfaces of each upper limb (total of 18% for both upper limbs). 3. Count four times nine, or 36%, for both the anterior and posterior surfaces of the trunk, including the buttocks. 4. Count 9% for the anterior and 9% for the posterior surfaces of each lower limb as far up as the buttocks (total of 36% for both lower limbs). 5. Count 1% for the perineum. This is known as?

centrosome

Pair of centrioles plus pericentriolar material. The pericentriolar material contains tubulins, which are used for growth of the mitotic spindle and microtubule formation.

facilitated diffusion

Passive movement of a substance down its concentration gradient through the lipid bilayer by transmembrane proteins that function as channels or carriers. Polar or charged solutes: glucose; fructose; galactose; some vitamins; and ions are transported this way.

simple diffusion

Passive movement of a substance down its concentration gradient through the lipid bilayer of the plasma membrane without the help of membrane transport proteins. Nonpolar, hydrophobic solutes: oxygen, carbon dioxide, and nitrogen gases; fatty acids; steroids; and fat-soluble vitamins. Polar molecules such as water, urea, and small alcohols are transported this way.

glucose

In cellular respiration ___________ is broken down to create energy to make ADP into ATP.

oligodendrocyte

These resemble astrocytes but are smaller and contain fewer processes. ________________ processes are responsible for forming and maintaining the myelin sheath around CNS axons. As you will see shortly, the myelin sheath is a multilayered lipid and protein covering around some axons that insulates them and increases the speed of nerve impulse conduction. Such axons are said to be myelinated.

astrocytes

These star- shaped cells have many processes and are the largest and most numerous of the neuroglia. There are two main types: protoplasmic, and fibrous. The fibrous have many long unbranched processes and are located mainly in white matter. The processes make contact with blood capillaries, neurons, and the pia mater (a thin membrane around the brain and spinal cord). Features of these neuroglia: -contain microfilaments that give them considerable strength, which enables them to support neurons. - processes of these wrapped around blood capillaries isolate neurons of the CNS from various potentially harmful substances in blood by secreting chemicals that maintain the unique selective permeability characteristics of the endothelial cells of the capillaries. In effect, the endothelial cells create a blood-brain barrier, which restricts the movement of substances between the blood and interstitial fluid of the CNS. - In the embryo, they secrete chemicals that appear to regulate the growth, migration, and interconnection among neurons in the brain. - help to maintain the appropriate chemical environment for the generation of nerve impulses. -may also play a role in learning and memory by influencing the formation of neural synapses

hinge joints

These synovial joints (axis of rotation at right angles to long axis of bone) flexion-extension movements only permitted. Examples include elbow, knee (modified hinge), interphalangeal joints. In these joints, only one axis of movement is permitted.

ball and socket joints

These synovial joints are multiaxial- they allow an infinite number of axes of rotation. There are only two in the body, the hip joint, and shoulder joint.

catalytic proteins

These types of proteins act enzymes that regulates biochemical reactions. Examples: salivary amylase; sucrase; ATPase.

ATP

This molecule transfers the energy liberated in exergonic catabolic reactions to power cellular activities that require energy (endergonic reactions).

regulatory proteins

This protein functions as hormones that regulate various physiological processes; control growth and development; as neurotransmitters, mediate responses of nervous system. Examples: the hormone insulin (regulates blood glucose level); the neurotransmitter known as substance P (mediates sensation of pain in nervous system).

transfer RNA

This type of RNA binds to an amino acid and holds it in place on a ribosome until it is incorporated into a protein during translation. One end of it carries a specific amino acid, and the opposite end consists of a triplet of nucleotides called an anticodon.

ribosomal RNA

This type of RNA joins with ribosomal proteins to make ribosomes

ependymal cells

This type of neuroglia are cuboidal to columnar cells arranged in a single layer that possess microvilli and cilia. -These cells line the ventricles of the brain and central canal of the spinal cord (spaces filled with cerebrospinal fluid, which protects and nourishes the brain and spinal cord). -Functionally, they produce, possibly monitor, and assist in the circulation of cerebrospinal fluid. They also form the blood-cerebrospinal fluid barrier.

contractile proteins

This type of protein allows shortening of muscle cells, which produces movement. Examples: myosin; actin.

transport proteins

This type of protein carries vital substances throughout body. Example: hemoglobin (transports most oxygen and some carbon dioxide in blood).

structural proteins

This type of protein forms structural framework of various parts of body. Examples: collagen in bone and other connective tissues; keratin in skin, hair, and fingernails.

contractile proteins, myosin, actin

This type of protein in myofibrils is responsible for generating force during contraction. Name two types.

regulatory proteins, tropomyosin, troponin

This type of protein in myofibrils is responsible for switching the muscle contractions on and off. Name two different ones.

structural proteins

This type of protein in myofibrils keep the thick and thin filaments in the proper alignment, give the myofibril elasticity and extensibility, and link the myofibrils to the sarcolemma and extracellular matrix.

immunological proteins

This type of proteins aids responses that protect body against foreign substances and invading pathogens. Examples: antibodies; interleukins.

hypertonic solution

This type of solution has a higher concentration of solutes than does the fluid inside the cell, therefore water molecules want to move out of the cell faster than they enter, causing cell shrinkage

saddle joint

This type of synovial joint is like two saddles with concave surfaces coming in contact. The only example is the carpometacarpal joint of the thumb

gliding joints

This type of synovial joints have a simple movement in which relatively flat bone surfaces move back-and-forth and from side-to-side with respect to one another. There is no significant alteration of the angle between the bones. The movement of these joints is limited in range due to the structure of the articular articular capsule and associated ligaments and bones.

transverse tubules, interstitial fluid

Thousands of tiny invaginations of the sarcolemma, called ___________. They are filled with ______________

cone photopigments

Three different _________________ are present in the retina, one in each of the three types of cones.

enzymes are highly specific (They only bind to specific substrates), enzymes are very efficient, enzymes are subject to a variety of cellular controls

Three important properties of enzymes are as follows:

rods, cones

_____ and _______ were named for the different appearance of the outer segment—the distal end next to the pigmented layer—of each of these types of photoreceptors. The outer segments of _(first blank)_ are cylindrical or rod-shaped; those of _(second blank)_ are tapered or cone-shaped

RNA

________ the second type of nucleic acid, relays instructions from the genes to guide each cell's synthesis of proteins from amino acids.

DNA

_________ forms the inherited genetic material inside each human cell. In humans, each gene is a segment of _(same)_

steroids, bile salts, sex hormones, vitamins, cholesterol

__________ are lipid molecules that have 4 rings of carbon. They include: ___________, ____________, ____________, _____________.

nucleic acids

____________ are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. There are two varieties, DNA and RNA.

perimysium

____________ is also a layer of dense, irregular connective tissue, but it surrounds groups of 10 to 100 or more muscle fibers, separating them into bun- dles called fascicles

phospholipids

_____________ have a glycerol backbone and two fatty acid chains attached to the first two carbons. The head is polar. The two tails are hydrophobic and nonpolar. These __(same)___ make up much of the cell membrane

endomysium

_____________ penetrates the interior of each fascicle and separates individual muscle fibers from one another. It is mostly reticular fibers.

triglycerides

_____________ provide more than twice as much energy per gram as do carbohydrates and proteins.

cytoplasm

______________ consists of all the cellular contents between the plasma membrane and the nucleus.

globular proteins

_______________ are more or less soluble in water and their polypeptide chains are spherical in shape. These have metabolic functions. Examples include enzymes, which function as catalysts; antibodies and complement proteins, which help protect us against disease; hemoglobin, which transports oxygen; lipoproteins, which transport lipids and cholesterol; albumins, which help regulate blood pH; membrane proteins, which transport substances into and out of cells; and some hormones such as insulin, which helps regulate blood sugar level.

tight junctions

_______________ consist of web-like strands of transmembrane proteins that fuse together the outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells. Cells of epithelial tissues that line the stomach, intestines, and urinary bladder have these cell junctions. They inhibit the passage of substances between cells and prevent the contents of these organs from leaking into the blood or surrounding tissues.

adherens junctions

_______________ contain plaque (PLAK), a dense layer of proteins on the inside of the plasma membrane that attaches both to membrane proteins and to microfilaments of the cytoskeleton. Transmembrane glycoproteins called cadherins join the cells. Each cadherin inserts into the plaque from the opposite side of the plasma membrane, partially crosses the intercellular space (the space between the cells), and connects to cadherins of an adjacent cell. In epithelial cells, these cell junctions often form extensive zones called adhesion belts because they encircle the cell similar to the way a belt encircles your waist. They help epithelial surfaces resist separation during various contractile activities, as when food moves through the intestines.

carbohydrates

_______________ include sugars, glycogen, starches, and cellulose. Even though they are a large and diverse group of organic compounds and have several functions, they represent only 2-3% of your total body mass. In humans and animals, they function mainly as a source of chemical energy for generating ATP needed to drive metabolic reactions. Only a few are used for building structural units. One example is deoxyribose, a type of sugar that is a building block of deoxyribonucleic acid (DNA), the molecule that carries inherited genetic information.

homeostasis

_______________ is the condition of equilibrium (balance) in the body's internal environment due to the constant interaction of the body's many regulatory processes. ___(same as above)__ is a dynamic condition. In response to changing conditions, the body's equilibrium can shift among points in a narrow range that is compatible with maintaining life. For example, the level of glucose in blood normally stays between 70 and 110 milligrams of glucose per 100 milliliters of blood.* Each structure, from the cellular level to the system level, contributes in some way to keeping the internal environment of the body within normal limits. -

transcription, translation

_______________ is the process of converting the genetic information stored in DNA to messenger RNA (mRNA). This is performed by RNA Polymerase in the nucleus of the cell (assuming the organism is eukaryotic). At this point the mRNA is comprised of exons and introns, (i.e. expressed regions and non-expressed regions) and the introns are cut out with splicing machinery. Now the mRNA is exported from the nucleus into the cytoplasm where it meets the ribosome. The ribosome uses the information stored in the mRNA, along with transfer RNAs (tRNA) holding onto amino acids to create protein. This process is known as ______________ because you are translating from the language of nucleotides to the language of amino acids.

fibrous proteins

________________ are insoluble in water and their polypeptide chains form long strands that are parallel to each other. They have many structural functions. Examples include collagen (strengthens bones, ligaments, and tendons), elastin (provides stretch in skin, blood vessels, and lung tissue), keratin (forms structure of hair and nails and waterproofs the skin), dystrophin (reinforces parts of muscle cells), fibrin (forms blood clots), and actin and myosin (are involved in contraction of muscle cells, division in all cells, and transport of substances within cells).

vestibule, utricle, saccule, semicircular canals, ampulla, semicircular ducts

The __________ is the oval central portion of the bony labyrinth. The membranous labyrinth in the vestibule consists of two sacs called the __________ and the __________, which are connected by a small duct. Projecting superiorly and posteriorly from the vestibule are the three bony ________________, each of which lies at approximately right angles to the other two. Based on their positions, they are named the anterior, posterior, and lateral canals. The anterior and posterior canals are vertically oriented; the lateral one is horizontally oriented. At one end of each canal is a swollen enlargement called the ___________. The portions of the membranous labyrinth that lie inside the canals are called the _______________. These structures connect with the utricle of the vestibule.

ATP hydrolysis, attachment of myosin to actin to form cross bridges, power stroke, detachment of myosin from actin

The contraction cycle: 1.The myosin head includes an ATP-binding site and an ATPase, an enzyme that hydrolyzes ATP into ADP (adenosine diphosphate) and a phosphate group. This hydrolysis reaction reorients and energizes the myosin head. Notice that the products of ATP hydrolysis—ADP and a phosphate group—are still attached to the myosin head. 2.The energized myosin head attaches to the myosin-binding site on actin and releases the previously hydrolyzed phosphate group. When the myosin heads attach to actin during contraction, they are referred to as cross-bridges. 3. After the cross-bridges form, the power stroke occurs. During the power stroke, the site on the cross-bridge where ADP is still bound opens. As a result, the cross-bridge rotates and releases the ADP. The cross- bridge generates force as it rotates toward the center of the sarcomere, sliding the thin filament past the thick filament toward the M line. 4. At the end of the power stroke, the cross-bridge remains firmly attached to actin until it binds another molecule of ATP. As ATP binds to the ATP- binding site on the myosin head, the myosin head detaches from actin.

RNA polymerase

The enzyme ______________ catalyzes transcription of DNA.

ATPase

The enzyme that catalyzes the hydrolysis of ATP is called ___________.

synovial membrane

The inner layer of the articular capsule, the _________________, is composed of areolar connective tissue with elastic fibers.

labyrinth, bony labyrinth, membranous labyrinth

The internal ear is also called the __________ because of its complicated series of canals. It has two main divisions: ______________ which contains perilymph, as well as the ________________, which contains endolymph

amino acids

The monomers of proteins are ____________ Each of the 20 different ones have a hydrogen (H) atom and three important functional groups attached to a central carbon atom each: (1) an amino group (ONH2), (2) an acidic carboxyl group (OCOOH), and (3) a side chain (R group). At the normal pH of body fluids, both the amino group and the carboxyl group are ionized.

triglycerides

The most plentiful lipids in your body and in your diet are the ____________.

epimysium

The outermost layer of dense, irregular connective tissue, encircling the entire muscle, is the ___________.

reflex arc, sensory neuron, integrating center, motor neuron, effector

The pathway followed by nerve impulses that produce a reflex is a __________. - It includes the following five main components: 1. _______________ 2. _______________ 3. _______________ 4. _______________ 5. _______________

motor end plate, acetylcholine receptors

The region of the sarcolemma opposite the synaptic end bulbs, called the _____________, is the muscle fiber part of the NMJ. Within each __(same as before)__ are 30 million to 40 million ____________________, integral transmembrane proteins to which ACh specifically binds.

contraction cycle, ATP hydrolysis, attachment of myosin to actin to form cross bridges, power stroke, detachment of myosin from actin

The repeating sequence of events that causes filaments to slide past each other. What are the four steps?

endochondral ossification

The replacement of cartilage by bone is called ___________________. Although most bones of the body are formed in this way, the process is best observed in long bones.

endochondral ossification

The replacement of cartilage by bone is called ___________________. Although most bones of the body are formed in this way, the process is best observed in long bones. The steps are as follows: -Development of the cartilage model. At the site where the bone is going to form, specific chemical messages cause the mesenchymal cells to crowd together in the general shape of the future bone, and then develop into chondroblasts. The chondroblasts secrete cartilage extracellular matrix, producing a cartilage model consisting of hyaline cartilage. A covering called the perichondrium develops around the cartilage model. -Growth of the cartilage model. Once chondroblasts become deeply buried in the cartilage extracellular matrix, they are called chondrocytes. The cartilage model grows in length by continual cell division of chondrocytes, accompanied by further secretion of the cartilage extracellular matrix. This type of cartilaginous growth, called interstitial (endogenous) growth (growth from within), results in an increase in length. In contrast, growth of the cartilage in thickness is due mainly to the deposition of extracellular matrix material on the cartilage surface of the model by new chondroblasts that develop from the perichondrium. This process is called appositional (exogenous) growth, meaning growth at the outer surface. As the cartilage model continues to grow, chondrocytes in its mid-region hypertrophy (increase in size) and the surrounding cartilage extracellular matrix begins to calcify. Other chondrocytes within the calcifying cartilage die because nutrients can no longer diffuse quickly enough through the extracellular matrix. As these chondrocytes die, the spaces left behind by dead chondrocytes merge into small cavities called lacunae. - Development of the primary ossification center. Primary ossification proceeds inward from the external surface of the bone. A nutrient artery penetrates the perichondrium and the calcifying cartilage model through a nutrient foramen in the mid-region of the cartilage model, stimulating osteogenic cells in the perichondrium to differentiate into osteoblasts. Once the perichondrium starts to form bone, it is known as the periosteum. Near the middle of the model, periosteal capillaries grow into the disintegrating calcified cartilage, inducing growth of a primary ossification center, a region where bone tissue will replace most of the cartilage. Osteoblasts then begin to deposit bone extracellular matrix over the remnants of calcified cartilage, forming spongy bone trabeculae. Primary ossification spreads from this central location toward both ends of the cartilage model. - Development of the medullary (marrow) cavity. As the primary ossification center grows toward the ends of the bone, osteoclasts break down some of the newly formed spongy bone trabeculae. This activity leaves a cavity, the medullary (marrow) cavity, in the diaphysis (shaft). Eventually, most of the wall of the diaphysis is replaced by compact bone. - Formation of articular cartilage and the epiphyseal (growth) plate. The hyaline cartilage that covers the epiphyses becomes the articular cartilage. Prior to adulthood, hyaline cartilage remains between the diaphysis and epiphysis as the epiphyseal (growth) plate, the region responsible for the lengthwise growth of long bones that you will learn about next.

calcium homeostasis

The role of bone in _________________ is to help "buffer" the blood Ca2+ level, releasing Ca2+ into blood plasma (using osteoclasts) when the level decreases, and absorbing Ca2+ (using osteoblasts) when the level rises.

calcium active transport pumps

The sarcoplasmic reticulum membrane also contains __________________ that use ATP to move Ca2+ constantly from the sarcoplasm back into the sarcoplasmic reticulum.

epidermis, dermis, hypodermis

The skin (cutaneous membrane), consists of two main parts: The superficial, thinner portion, which is composed of epithelial tissue, is the _____________. The deeper, thicker connective tissue portion is the ___________. While the epidermis is avascular, the dermis is vascular. Deep to the dermis, but not part of the skin, is the subcutaneous (subQ) layer. Also called the _____________, this layer consists of areolar and adipose tissues. Fibers that extend from the dermis anchor the skin to the subcutaneous layer, which in turn attaches to underlying fascia, the connective tissue around muscles and bones. The subcutaneous layer serves as a storage depot for fat and contains large blood vessels that supply the skin. This region (and sometimes the dermis) also contains nerve endings called pacinian (lamellated) corpuscles that are sensitive to pressure.

synovial joint

The unique characteristic of a ______________ is the presence of a space called a synovial (joint) cavity between the articulating bones. Because the synovial cavity allows considerable movement at a joint, all synovial joints are classified functionally as freely movable (diarthroses). The bones at a synovial joint are covered by a layer of hyaline cartilage called articular cartilage. The cartilage covers the articulating surface of the bones with a smooth, slippery surface but does not bind them together. Articular cartilage reduces friction between bones in the joint during movement and helps to absorb shock.

vestibular ganglia

The vestibular branch of the vestibulocochlear (VIII) nerve consists of ampullary, utricular, and saccular nerves. These nerves contain both first-order sensory neurons and motor neurons that synapse with receptors for equilibrium. The first-order sensory neurons carry sensory information from the receptors, and the motor neurons carry feedback signals to the receptors, apparently to modify their sensitivity. Cell bodies of the sensory neurons are located in the ________________.

Schwann cells

These cells encircle PNS axons. Like oligodendrocytes, they form the myelin sheath around axons. -However, a single oligodendrocyte myelinates several axons, but each Schwann cell myelinates a single axon. - A single one of these cells can also enclose as many as 20 or more unmyelinated axons (axons that lack a myelin sheath). -These cells participate in axon regeneration, which is more easily accomplished in the PNS than in the CNS.

satellite cells

These flat cells surround the cell bodies of neurons of PNS ganglia. -Besides providing structural support, these cells regulate the exchanges of materials between neuronal cell bodies and interstitial fluid.

mucous membranes

These membranes are sheets of epithelial tissue resting on a layer of connective tissue, which usually has the name "lamina propria". All lamina propria, when present is loose connective tissue, usually bearing a fair amount of lymphoid tissue. All _________________ are topologically continuous with the outside of the body but like serous membranes, __(same)__ are moist. The definition therefore is a moist tissue consisting of epithelial and connective tissue, which lines tubes or cavities continuous with the surface of the body. Thus the linings of the digestive tube, the respiratory tree, the urinary tract and so on are all made of __(same)__. Keratinized stratified squamous epithelium is the only kind of epithelium which is not part of any __(same)__.

myofilaments, thin filaments, thick filaments, sarcomeres

Within myofibrils are smaller protein structures called filaments or ____________. _____________ are 8 nm in diameter and 1-2 mu m long† and composed mostly of the protein actin, while ______________ are 16 nm in diameter and 1-2 mu m long and composed mostly of the protein myosin. Both are directly involved in the contractile process. The filaments inside a myofibril do not extend the entire length of a muscle fiber. Instead, they are arranged in compartments called _____________.

fast oxidative glycolitic fibers

_________________ are intermediate in diameter between the other two types of fibers. Like slow oxidative fibers, they contain large amounts of myoglobin and many blood capillaries. Thus, they also have a dark red appearance. - These fibers fibers can generate considerable ATP by aerobic cellular respiration, which gives them a moderately high resistance to fatigue. Because their intracellular glycogen level is high, they also generate ATP by anaerobic glycolysis. -They are "fast" because the ATPase in their myosin heads hydrolyzes ATP three to five times faster than the myosin ATPase in slow oxidative fibers, which makes their speed of contraction faster. Thus, twitches of these fibers reach peak tension more quickly than those of slow oxidative fibers but are briefer in duration—less than 100 msec. -These fibers contribute to activities such as walking and sprinting.

slow oxidative fibers

_________________ are smallest in diameter and thus are the least powerful type of muscle fibers. They appear dark red because they contain large amounts of myoglobin and many blood capillaries. - Because they have many large mitochondria, they generate ATP mainly by aerobic cellular respiration. These fibers have a slow speed of contraction. Their twitch contractions last from 100 to 200 msec, and they take longer to reach peak tension. -However, these fibers are very resistant to fatigue and are capable of prolonged, sustained contractions for many hours.(marathon/endurance running)

monounsaturated fats

_________________ contain triglycerides that mostly consist of monounsaturated fatty acids. Olive oil, peanut oil, canola oil, most nuts, and avocados are rich in triglycerides with monounsaturated fatty acids. They are known to decrease risk of heart disease.

epithelial tissue membranes

__________________ are moist membranes consisting of a flat sheet of epithelial tissue overlying a layer of connective tissue. There are two varieties of epithelial membranes: Serous and Mucous.

Tendon sheaths

__________________ are tubelike bursae that wrap around certain tendons that experience considerable friction as they pass through tunnels formed by connective tissue and bone. The inner layer of these sheaths, the visceral layer, is attached to the surface of the tendon. The outer layer, known as the parietal layer, is attached to bone. Between the layers is a cavity that contains a film of synovial fluid. A tendon sheath protects all sides of a tendon from friction as the tendon slides back and forth. These sheaths are found where tendons pass through synovial cavities, such as the tendon of the biceps brachii muscle at the shoulder joint. They are also found at the wrist and ankle, where many tendons come together in a confined space, and in the fingers and toes, where there is a great deal of movement.

connective tissue membranes

__________________ consist of connective tissue alone. Examples are aponeuroses, dura, epimyseum, periosteum, perichondrium, ligamentum nuchae, and interosseous membranes. In other words, it is just a sheet of connective tissue, consisting of either collagenous fibers or elastic fibers.

anaerobic cellular respiration

__________________ is a series of ATP-producing reactions that do not require oxygen. When muscle activity continues and the supply of creatine phosphate within the muscle fibers is depleted, glucose is catabolized to generate ATP. Glucose easily passes from the blood into contracting muscle fibers via facilitated diffusion, and it is also produced by the breakdown of glycogen within muscle fibers. Then, a series of reactions known as glycolysis quickly breaks down each glucose molecule into two molecules of pyruvic acid. Glycolysis occurs in the cytosol and produces a net gain of two molecules of ATP.

reproductive cell division, meiosis

__________________ is the mechanism that produces gametes, the cells needed to form the next generation of sexually reproducing organisms. This process consists of a special two-step division called ___________, in which the number of chromosomes in the nucleus is reduced by half.

nucleus

a large organelle that houses most of a cell's DNA. Within this structure are chromosomes, which contain genes.

tRNA

complementary molecule to mRNA; each carrys an amino acid

mitochondria

consist of an outer and an inner mitochondrial membrane, cristae, and matrix; new ones form from preexisting ones. They are the sites of aerobic cellular respiration reactions that produce most of a cell's ATP. Play an important early role in apoptosis.

sliding filament mechanism

skeletal muscle shortens during contraction because the thick and thin filaments slide past one another. The model describing this process is known as the _________________.

glycogen

starches (polysaccharides) can be broken down into monosaccharides through hydrolysis reactions. For example, when the blood glucose level falls, liver cells break down ___________ into glucose and release it into the blood, making it available to body cells, which break it down to synthesize ATP.

translation

does transcription or translation take place in the ribosomes?

RNA

has uracil instead of thymine

exons

the part of the DNA carrying the code

active site

the part of the enzyme that catalyzes the reaction, called the _____________

sarcolemma

the plasma membrane of a muscle cell

translation

the process of making amino acids from a mRNA strand

neuromuscular junction

Muscle action potentials arise at the _______________, the synapse between a somatic motor neuron and a skeletal muscle fiber.

creatine phosphate, anaerobic cellular respiration, aerobic cellular respiration

Muscle fibers have three ways to produce ATP:

microglia

These neuroglia are small cells with slender processes that give off numerous spinelike projections. - They function as phagocytes. Like tissue macrophages, they remove cellular debris formed during normal development of the nervous system and phagocytize microbes and damaged nervous tissue.

calcium homeostasis

1. Bone is the major reservoir for calcium in the body. 2. Parathyroid hormone (PTH) secreted by the parathyroid glands increases blood Ca2+ level. Calcitonin (CT) from the thyroid gland has the potential to decrease blood Ca2+ level. Vitamin D enhances absorption of calcium and phosphate and thus raises the blood levels of these substances. This is describing what topic?

serous membrane

A type of epithelial tissue membrane that covers or likes the serous cavities of the body, namely the peritoneal, pericardial, and pleural cavities. These cavities are not continuous with the outside of the body. The names applied to these serous membranes are the peritoneum, the pericardium, and the pleura. Each of these membranes consists of a single layer of simple squamous epithelium, specifically named the mesothelium, backed up by a thin layer of loose connective tissue which appears unremarkable. The parietal layer of these serous membranes covers the inner surface of the body wall. Any organ of the peritoneal cavity, which protrudes into that serous cavity, but is not totally covered by the peritoneum and pushes that serous membrane ahead of it (like the kidney) is said to be retroperitoneal. When the peritoneum leaves the dorsal body wall to form a two-layered sandwich, with the connective tissue parts of the two membranes in contact with each other, the resulting structure is called a mesentery. A mesentery is defined then as a two-layered sheet of serous membrane attaching an organ to the dorsal body wall. Mesenteries support many of the body organs, the viscera, of the peritoneal cavity. The serous membrane then splits, going around each side of the viscera to envelope it in what is termed the visceral peritoneum. Any organ of the peritoneal cavity which is completely surrounded by this visceral peritoneum is said to be intraperitoneal. These organs are connected to a mesentery and are "swung by a mesentery". Most of the organs of the peritoneal cavity are either "retroperitoneal" or "intraperitoneal". Identify into which of these two categories each of the following organs can be classified.

ball and socket joint

A type of synovial joint called a ________________ or spheroid joint consists of the ball-like surface of one bone fitting into a cuplike depression of another bone. -Such joints are triaxial (multiaxial), permitting movements around three axes (flexion-extension, abduction-adduction, and rotation). -Examples are shoulder and hip joints.

diaphysis, epiphyses, metaphyses, articular cartilage, periosteum, medullary cavity

A typical long bone consists of the following parts:

homeostasis

An important aspect of ______________ is maintaining the volume and composition of body fluids, dilute, watery solutions containing dissolved chemicals that are found inside cells as well as surrounding them.

cochlea, modiolus, scala media, scala vestibuli, scala tympani, helicotrema, vestibular membrane, basilar membrane, spiral organ

Anterior to the vestibule is the ___________, a bony spiral canal that resembles a snail's shell and makes almost three turns around a central bony core called the ___________ . Sections through the cochlea reveal that it is divided into three channels: _____________, ___________, and ______________ . The cochlear duct is a continuation of the membranous labyrinth into the cochlea; it is filled with endolymph. The channel above the cochlear duct is the scala vestibuli, which ends at the oval window. The channel below is the scala tympani, which ends at the round window. Both the scala vestibuli and scala tympani are part of the bony labyrinth of the cochlea; therefore, these chambers are filled with perilymph. The scala vestibuli and scala tympani are completely separated by the cochlear duct, except for an opening at the apex of the cochlea, the ____________. The cochlea adjoins the wall of the vestibule, into which the scala vestibuli opens. The perilymph in the vestibule is continuous with that of the scala vestibuli. The _________________ separates the cochlear duct from the scala vestibuli, and the _______________separates the cochlear duct from the scala tympani. Resting on the basilar membrane is the ________________. This structure is a coiled sheet of epithelial cells, including supporting cells and about 16,000 hair cells, which are the receptors for hearing. There are two groups of hair cells: The inner hair cells are arranged in a single row, whereas the outer hair cells are arranged in three rows. At the apical tip of each hair cell are 40-80 stereocilia that extend into the endolymph of the cochlear duct. Despite their name, stereocilia are actually long, hairlike microvilli arranged in several rows of graded height.

isotonic solution

Any solution in which a cell maintains its normal shape and volume is an ______________. The concentrations of solutes that cannot cross the plasma membrane are the same on both sides of the membrane in this solution.

gap junctions

At _______________, membrane proteins called connexins form tiny fluid-filled tunnels called connexons that connect neighboring cells. The plasma membranes of __(same)__ are not fused together as in tight junctions but are separated by a very narrow intercellular gap (space). -Through the connexons, ions and small molecules can diffuse from the cytosol of one cell to another, but the passage of large molecules such as vital intracellular proteins is prevented. -The transfer of nutrients, and perhaps wastes, takes place through these cell junctions in avascular tissues such as the lens and cornea of the eye. They allow the cells in a tissue to communicate with one another. -In a developing embryo, some of the chemical and electrical signals that regulate growth and cell differentiation travel via __(same)__. They also enable nerve or muscle impulses to spread rapidly among cells, a process that is crucial for the normal operation of some parts of the nervous system and for the contraction of muscle in the heart, gastrointestinal tract, and uterus.

stratum granulosum

At about the middle of the epidermis, ______________, consists of three to five layers of flattened keratinocytes that are undergoing apoptosis. The nuclei and other organelles of these cells begin to degenerate as they move farther from their source of nutrition (the dermal blood vessels). Even though keratin intermediate filaments are no longer being produced by these cells, they become more apparent because the organelles in the cells are regressing. A distinctive feature of cells in this layer is the presence of darkly staining granules of a protein called keratohyalin, which assembles keratin intermediate filaments into keratin. Also present in the keratinocytes are membrane-enclosed lamellar granules, which fuse with the plasma membrane and release a lipid-rich secretion.This secretion is deposited in the spaces between cells of this layer, stratum lucidum, and stratum corneum. The lipid-rich secretion acts as a water- repellent sealant, retarding loss and entry of water and entry of foreign materials. As their nuclei break down during apoptosis, the keratinocytes of the stratum granulosum can no longer carry on vital metabolic reactions, and they die. Thus, the stratum granulosum marks the transition between the deeper, metabolically active strata and the dead cells of the more superficial strata.

A, B, C

Axons can be classified into three major groups based on the amount of myelination, their diameters, and their propagation speeds: -__ fibers are the largest-diameter axons (5-20 mu m) and are myelinated. A fibers have a brief absolute refractory period and conduct nerve impulses (action potentials) at speeds of 12 to 130 m/sec (27-290 mi/hr). The axons of sensory neurons that propagate impulses associated with touch, pressure, position of joints, and some thermal and pain sensations are A fibers, as are the axons of motor neurons that conduct impulses to skeletal muscles. - __ fibers are axons with diameters of 2-3 mu m. Like A fibers, B fibers are myelinated and exhibit saltatory conduction at speeds up to 15 m/sec (34 mi/hr). B fibers have a somewhat longer absolute refractory period than A fibers. These fibers conduct sensory nerve impulses from the viscera to the brain and spinal cord. They also constitute all the axons of the autonomic motor neurons that extend from the brain and spinal cord to the ANS relay stations called autonomic ganglia. -__ fibers are the smallest-diameter axons (0.5-1.5 mu m) and all are unmyelinated. Nerve impulse propagation along this fiber ranges from 0.5 to 2 m/sec (1-4 mi/hr). These fibers exhibit the longest absolute refractory periods. These unmyelinated axons conduct some sensory impulses for pain, touch, pressure, heat, and cold from the skin, and pain impulses from the viscera. Autonomic motor fibers that extend from autonomic ganglia to stimulate the heart, smooth muscle, and glands are these fibers.

epithelial tissues, connective tissues, muscular tissues, nervous tissues

Body tissues can be classified into four basic types according to their structure and function: -_______________ cover body surfaces and line hollow organs, body cavities, and ducts; they also forms glands. This tissue allows the body to interact with both its internal and external environments. - ______________ protect and support the body and its organs. Various types of connective tissues bind organs together, store energy reserves as fat, and help provide the body with immunity to disease-causing organisms. - _______________ are composed of cells specialized for contraction and generation of force. In the process, muscular tissues generate heat that warms the body. - _______________ detect changes in a variety of conditions in-side and outside the body and responds by generating electrical signals called nerve action potentials (nerve impulses) that activate muscular contractions and glandular secretions.

calcium

Bone is the body's major ___________ reservoir, storing 99% of total body calcium. One way to maintain the level of calcium in the blood is to control the rates of calcium resorption from bone into blood and of calcium deposition from blood into bone. Both nerve and muscle cells depend on a stable level of calcium ions (Ca2+) in extracellular fluid to function properly. Blood clotting also requires Ca2+. Also, many enzymes require Ca2+ as a cofactor (an additional substance needed for an enzymatic reaction to occur). For this reason, the blood plasma level of Ca2+ is very closely regulated between 9 and 11 mg/100 mL. Even small changes in Ca2+ concentration outside this range may prove fatal—the heart may stop (cardiac arrest) if the concentration goes too high, or breathing may cease (respiratory arrest) if the level falls too low. The role of bone in calcium homeostasis is to help "buffer" the blood Ca2+ level, releasing Ca2+ into blood plasma (using osteoclasts) when the level decreases, and absorbing Ca2+ (using osteoblasts) when the level rises. Ca2+ exchange is regulated by hormones, the most important of which is parathyroid hormone (PTH) secreted by the parathyroid glands. This hormone increases blood Ca2+ level. PTH secretion operates via a negative feedback system. If some stimulus causes the blood Ca2+ level to decrease, parathyroid gland cells (receptors) detect this change and increase their production of a molecule known as cyclic adenosine monophosphate (cyclic AMP). The gene for PTH within the nucleus of a parathyroid gland cell (the control center) detects the intracellular increase in cyclic AMP (the input). As a result, PTH synthesis speeds up, and more PTH (the output) is released into the blood. The presence of higher levels of PTH increases the number and activity of osteoclasts (effectors), which step up the pace of bone resorption. The resulting release of Ca2+ from bone into blood returns the blood Ca2+ level to normal. PTH also acts on the kidneys (effectors) to decrease loss of Ca2+ in the urine, so more is retained in the blood. And PTH stimulates formation of calcitriol (the active form of vitamin D), a hormone that promotes absorption of calcium from foods in the gastrointestinal tract into the blood. Both of these actions also help elevate blood Ca2+ level. Another hormone works to decrease blood Ca2+ level. When blood Ca2+ rises above normal, parafollicular cells in the thyroid gland secrete calcitonin (CT). CT inhibits activity of osteoclasts, speeds blood Ca2+ uptake by bone, and accelerates Ca2+ deposition into bones. The net result is that CT promotes bone formation and decreases blood Ca2+ level. Despite these effects, the role of CT in normal calcium homeostasis is uncertain because it can be completely absent without causing symptoms. Nevertheless, calcitonin harvested from salmon (Miacalcin®) is an effective drug for treating osteoporosis because it slows bone resorption.

23,46

Human cells, such as those in the brain, stomach, and kidneys, contain ___ pairs of chromosomes, for a total of ___. One member of each pair is inherited from each parent.

hinge joint

In a synovial joint called a __________, or ginglymus joint, the convex surface of one bone fits into the concave surface of another bone. As the name implies, these joints produce an angular, opening-and-closing motion. In most joint movements, one bone remains in a fixed position while the other moves around an axis. These joints are uniaxial (monaxial), because they typically allow motion around a single axis. -These joints permit only flexion and extension. Examples of these joints are the knee (actually a modified hinge joint, which will be described later), elbow, ankle, and interphalangeal joints (between the phalanges of the fingers and toes).

condyloid joint

In a synovial joint called a ______________ or ellipsoidal joint, the convex oval-shaped projection of one bone fits into the oval-shaped depression of another bone. -such a joint is biaxial because the movement it permits is around two axes (flexion-extension and abduction-adduction). -Examples are the radiocarpal (wrist) and metacarpophalangeal joints (between the metacarpals and proximal phalanges) of the second through fifth digits.

enzymes

In living cells, most catalysts are protein molecules called ____________.

mitosis, cytokinesis

In somatic cell division, a cell undergoes a nuclear division called ___________, and a cytoplasmic division called ___________.

alpha receptors, beta receptors

In the ANS, the adrenergic neurons release norepinephrine (NE), also known as noradrenalin. Most sympathetic postganglionic neurons are adrenergic. Like ACh, NE is stored in synaptic vesicles and released by exocytosis. Molecules of NE diffuse across the synaptic cleft and bind to specific adrenergic receptors on the postsynaptic membrane, causing either excitation or inhibition of the effector cell. Adrenergic receptors bind both norepinephrine and epinephrine. The norepinephrine can be either released as a neurotransmitter by sympathetic postganglionic neurons or released as a hormone into the blood by chromaffin cells of the adrenal medullae; epinephrine is released as a hormone. The two main types of adrenergic receptors are _______________ and ________________, which are found on visceral effectors innervated by most sympathetic postganglionic axons.

translation

In the process of translation, the nucleotide sequence in an mRNA molecule specifies the amino acid sequence of a protein. Ribosomes in the cytoplasm carry out translation. The small sub- unit of a ribosome has a binding site for mRNA; the large subunit has two binding sites for tRNA molecules, a P site and an A site. The first tRNA molecule bearing its specific amino acid attaches to mRNA at the P site. The A site holds the next tRNA molecule bearing its amino acid. Translation occurs in the following way: 1 An mRNA molecule binds to the small ribosomal subunit at the mRNA binding site. A special tRNA, called initiator tRNA, binds to the start codon (AUG) on mRNA, where translation begins. The tRNA anticodon (UAC) attaches to the mRNA codon (AUG) by pairing between the complementary bases. Besides being the start codon, AUG is also the codon for the amino acid methionine. Thus, methionine is always the first amino acid in a growing polypeptide. ●2 Next, the large ribosomal subunit attaches to the small ribo- somal subunit-mRNA complex, creating a functional ribo- some. The initiator tRNA, with its amino acid (methionine), fits into the P site of the ribosome. ●3 The anticodon of another tRNA with its attached amino acid pairs with the second mRNA codon at the A site of the ribo- some. ●4 A component of the large ribosomal subunit catalyzes the formation of a peptide bond between methionine, which sep- arates from its tRNA at the P site, and the amino acid carried by the tRNA at the A site. ●5 After peptide bond formation, the tRNA at the P site detaches from the ribosome, and the ribosome shifts the mRNA strand by one codon. The tRNA in the A site bearing the two-peptide protein shifts into the P site, allowing another tRNA with its amino acid to bind to a newly exposed codon at the A site. Steps ●3 through ●5 occur repeatedly, and the protein length- ens progressively. ●6 Protein synthesis ends when the ribosome reaches a stop codon, which causes the completed protein to detach from the final tRNA. When the tRNA vacates the ribosome, the ri- bosome splits into its large and small subunits.

synovial joint

In this joint, bones are united with joint cavity, synovial membranes, etc.

inflammatory phase, inflammation

In this phase of wound healing, a blood clot forms in the wound and loosely unites the wound edges. As its name implies, this phase of deep wound healing involves _____________, a vascular and cellular response that helps eliminate microbes, foreign materials, and dying tissues in preparation for repair. The vasodilation and increased permeability of blood vessels associated with _(same as above)_ enhance delivery of helpful cells. These include phagocytic white blood cells called neutrophils; monocytes, which develop into macrophages that phagocytize microbes; and mesenchymal cells, which develop into fibroblasts.

intramembranous ossification

Intramembranous ossification is the simpler of the two methods of bone formation. The flat bones of the skull, most of the facial bones, mandible (lower jawbone), and the medial part of the clavicle (collar bone) are formed in this way. Also, the "soft spots" that help the fetal skull pass through the birth canal later harden as they undergo intramembranous ossification, which occurs as follows: -Development of the ossification center. At the site where the bone will develop, specific chemical messages cause the mesenchymal cells to cluster together and differentiate, first into osteogenic cells and then into osteoblasts. The site of such a cluster is called an ossification center. Osteoblasts se- crete the organic extracellular matrix of bone until they are surrounded by it. -Calcification.Next,the secretion of extracellular matrix stops, and the cells, now called osteocytes, lie in lacunae and extend their narrow cytoplasmic processes into canaliculi that radiate in all directions. Within a few days, calcium and other mineral salts are deposited and the extracellular matrix hard- ens or calcifies (calcification). -Formation of trabeculae. As the bone extracellular matrix forms, it develops into trabeculae that fuse with one another to form spongy bone around the network of blood vessels in the tissue. Connective tissue that is associated with the blood vessels in the trabeculae differentiates into red bone marrow. -Development of the periosteum. In conjunction with the formation of trabeculae, the mesenchyme condenses at the periphery of the bone and develops into the periosteum. Eventually, a thin layer of compact bone replaces the surface layers of the spongy bone, but spongy bone remains in the center. Much of the newly formed bone is remodeled (destroyed and reformed) as the bone is transformed into its adult size and shape.

inflammation

a vascular and cellular response that helps eliminate microbes, foreign materials, and dying tissues in preparation for repair.

epidermis

The ___________ is composed of keratinized stratified squamous epithelium. It contains four principal types of cells: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. About 90% of these cells are keratinocytes, which are arranged in four or five layers and produce the protein keratin. About 8% of these cells are melanocytes, which develop from the ectoderm of a developing embryo and produce the pigment melanin. Their long, slender projections extend between the keratinocytes and transfer melanin granules to them. Melanin is a yellow-red or brown-black pigment that contributes to skin color and absorbs damaging ultraviolet (UV) light. Langerhans Cells also called epidermal dendritic cells, arise from red bone marrow and migrate to the epidermis, where they constitute a small fraction of the epidermal cells. They participate in immune responses mounted against microbes that invade the skin, and are easily damaged by UV light. Their role in the immune response is to help other cells of the immune system recognize an invading microbe and destroy it. Merkel cells are the least numerous of the epidermal cells. They are located in the deepest layer of the epidermis, where they contact the flattened process of a sensory neuron (nerve cell), a structure called a Merkel (tactile) disc. Merkel cells and their associated Merkel discs detect touch sensations.

stratum corneum

The _____________ consists on average of 25 to 30 layers of flattened dead keratinocytes, but can range in thickness from a few cells in thin skin to 50 or more cell layers in thick skin. The cells are extremely thin, flat, plasma membrane-enclosed packages of keratin that no longer contain a nucleus or any internal organelles. They are the final product of the differentiation process of the keratinocytes. The cells within each layer overlap one another like the scales on the skin of a snake. Neighboring layers of cells also form strong connections with one another. The plasma membranes of adjacent cells are arranged in complex, wavy folds that fit together like pieces of a jigsaw puzzle to hold the layers together. In this outer stratum of the epidermis, cells are continuously shed and replaced by cells from the deeper strata. Its multiple layers of dead cells help this skin layer to protect deeper layers from injury and microbial invasion. Constant exposure of skin to friction stimulates increased cell production and keratin production that results in the formation of a callus, an abnormal thickening of this layer.

limbic system

The _____________ is sometimes called the "emotional brain" because it plays a primary role in a range of emotions, including pain, pleasure, docility, affection, and anger. It also is involved in olfaction (smell) and memory. -Experiments have shown that when different areas of animals' __(same)__s are stimulated, the animals' reactions indicate that they are experiencing intense pain or extreme pleasure. -Stimulation of other areas of this system in animals produces tameness and signs of affection. -Stimulation of a cat's amygdala or certain nuclei of the hypothalamus produces a behavioral pattern called rage—the cat extends its claws, raises its tail, opens its eyes wide, hisses, and spits. -By contrast, removal of the amygdala produces an animal that lacks fear and aggression. -Likewise, a person whose amygdala is damaged fails to recognize fearful expressions in others or to express fear in situations where this emotion would normally be appropriate, for example, while being attacked by an animal. -Together with parts of the cerebrum, the limbic system also functions in memory; damage to the __(same)__ causes memory impairment. One portion of the __(same)__, the hippocampus, is seemingly unique among structures of the central nervous system—it has cells reported to be capable of mitosis. Thus, the portion of the brain that is responsible for some aspects of memory may develop new neurons, even in the elderly.

stretch reflex

The _____________ occurs as follow: 1. Slight stretching of a muscle stimulates sensory receptors in the muscle called muscle spindles. The spindles 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 (integrating center), 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 arise in the motor neuron and propagate 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 neuron form neuromuscular junctions (NMJs) with skeletal muscle fibers of the stretched muscle. 5. Acetylcholine released by nerve impulses at the NMJs triggers one or more muscle action potentials in the stretched muscle (effector), and the muscle contracts. Thus, muscle stretch is followed by muscle contraction, which relieves the stretching.

thalamus

The _____________, which measures about 3 cm (1.2 in.) in length and makes up 80% of the diencephalon, consists of paired oval masses of gray matter organized into nuclei with interspersed tracts of white matter. The _(same)_ is the major relay station for most sensory impulses that reach the primary sensory areas of the cerebral cortex from the spinal cord and brain stem. In addition, the _(same)_ contributes to motor functions by transmitting information from the cerebellum and basal nuclei to the primary motor area of the cerebral cortex. The _(same)_ also relays nerve impulses between different areas of the cerebrum and plays a role in the maintenance of consciousness. Based on their positions and functions, there are seven major groups of nuclei on each side of the _(same)_ 1. The anterior nucleus- receives input from the hypothalamus and sends output to the limbic system. It functions in emotions and memory. 2. The medial nuclei- receive input from the limbic system and basal nuclei and send output to the cerebral cortex. They function in emotions, learning, memory, and cognition (thinking and knowing). 3. Nuclei in the lateral group- receive input from the limbic system, superior colliculi, and cerebral cortex and send output to the cerebral cortex. The lateral dorsal nucleus functions in the expression of emotions. The lateral posterior nucleus and pulvinar nucleus help integrate sensory information. 4. Five nuclei are part of the ventral group. The ventral anterior nucleus receives input from the basal nuclei and sends output to motor areas of the cerebral cortex; it plays a role in movement control. The ventral lateral nucleus receives input from the cerebellum and basal nuclei and sends output to motor areas of the cerebral cortex; it also plays a role in movement control. The ventral posterior nucleus relays impulses for somatic sensations such as touch, pressure, vibration, itch, tickle, temperature, pain, and proprioception from the face and body to the cerebral cortex. The lateral geniculate nucleus relays visual impulses for sight from the retina to the primary visual area of the cerebral cortex. The medial geniculate nucleus relays auditory impulses for hearing from the ear to the primary auditory area of the cerebral cortex. 5. Intralaminar nuclei lie within the internal medullary lamina and make connections with the reticular formation, cerebellum, basal nuclei, and wide areas of the cerebral cortex. They function in arousal (activation of the cerebral cortex from the brain stem reticular formation) and integration of sensory and motor information. 6. The midline nucleus forms a thin band adjacent to the third ventricle and has a presumed function in memory and olfaction. 7. The reticular nucleus surrounds the lateral aspect of the thalamus, next to the internal capsule. This nucleus monitors, filters, and integrates activities of other thalamic nuclei.

periosteum

The ______________ is a tough connective tissue sheath and its associated blood supply that surrounds the bone surface wherever it is not covered by articular cartilage. It is composed of an outer fibrous layer of dense irregular connective tissue and an inner osteogenic layer that consists of cells. Some of the cells enable bone to grow in thickness, but not in length. The __(same)__ also protects the bone, assists in fracture repair, helps nourish bone tissue, and serves as an attachment point for ligaments and tendons. It is attached to the underlying bone by perforating (Sharpey's) fibers, thick bundles of collagen that extend from the __(same)__ into the bone extracellular matrix.

hypothalamus

The _______________ is a small part of the diencephalon located inferior to the thalamus. It is composed of a dozen or so nuclei in four major regions: 1. The mammillary region, adjacent to the midbrain, is the most posterior part of the hypothalamus. It includes the mammillary bodies and posterior hypothalamic nuclei. The mammillary bodies serve as relay stations for reflexes related to the sense of smell. 2.The tuberal region,the widest part of the hypothalamus, includes the dorsomedial nucleus, ventromedial nucleus, and arcuate nucleus, plus the stalklike infundibulum, which connects the pituitary gland to the hypothalamus. The median eminence is a slightly raised region that encircles the infundibulum. 3. The supraoptic region lies superior to the optic chiasm (point of crossing of optic nerves) and contains the paraventricular nucleus, supraoptic nucleus, anterior hypothalamic nucleus, and suprachiasmatic nucleus. Axons from the paraventricular and supraoptic nuclei form the hypothalamo-hypophyseal tract, which extends through the infundibulum to the posterior lobe of the pituitary. 4. The preoptic region anterior to the supraoptic region is usually considered part of the hypothalamus because it participates with the hypothalamus in regulating certain autonomic activities. The preoptic region contains the medial and lateral preoptic nuclei.

stratum lucidum

The _______________ is present only in the thick skin of areas such as the fingertips, palms, and soles. It consists of four to six layers of flattened clear, dead keratinocytes that contain large amounts of keratin and thickened plasma membranes. This probably provides an additional level of toughness in this region of thick skin.

basal ganglia

The _______________ receive input from the cerebral cortex and provide output to motor parts of the cortex via the medial and ventral group nuclei of the thalamus. In addition, the _(same)_ have extensive connections with one another. A major function of the _(same)_ is to help regulate initiation and termination of movements. Activity of neurons in the putamen precedes or anticipates body movements; activity of neurons in the caudate nucleus occurs prior to eye movements. The globus pallidus helps regulate the muscle tone required for specific body movements. The basal nuclei also control subconscious contractions of skeletal muscles. Examples include automatic arm swings while walking and true laughter in response to a joke. In addition to influencing motor functions, the basal nuclei have other roles. They help initiate and terminate some cognitive processes, such as attention, memory, and planning, and may act with the limbic system to regulate emotional behaviors. Disorders such as Parkinson disease, obsessive-compulsive disorder, schizophrenia, and chronic anxiety are thought to involve dysfunction of circuits between the _(same)_ and the limbic system.

prefrontal cortex

The _______________, is an extensive area in the anterior portion of the frontal lobe that is well developed in primates, especially humans. This area has numerous connections with other areas of the cerebral cortex, thalamus, hypothalamus, limbic system, and cerebellum. The prefrontal cortex is concerned with the makeup of a person's personality, intellect, complex learning abilities, recall of information, initiative, judgment, foresight, reasoning, conscience, intuition, mood, planning for the future, and development of abstract ideas. -A person with bilateral damage to this area typically becomes rude, inconsiderate, incapable of accepting advice, moody, inattentive, less creative, unable to plan for the future, and incapable of anticipating the consequences of rash or reckless words or behavior.

medullary cavity

The _________________, or marrow cavity, is a hollow, cylindrical space within the diaphysis that contains fatty yellow bone marrow and numerous blood vessels in adults. This cavity minimizes the weight of the bone by reducing the dense bony material where it is least needed. The long bones' tubular design provides maximum strength with minimum weight.

plasma membrane

The __________________ forms the cell's flexible outer surface, separating the cell's internal environment (everything inside the cell) from the external environment (everything outside the cell). It is a selective barrier that regulates the flow of materials into and out of a cell. This selectivity helps establish and maintain the appropriate environment for normal cellular activities. The plasma membrane also plays a key role in communication among cells and between cells and their external environment.

tectorial membrane

The ____________________, a flexible gelatinous membrane, covers the hair cells of the spiral organ. In fact, the ends of the stereocilia of the hair cells are embedded in this structure while the bodies of the hair cells rest on the basilar membrane.

peripheral nervous system

The ______________________ consists of all nervous tissue outside the CNS. -Components include nerves, ganglia, enteric plexuses, and sensory receptors. A nerve is a bundle of hundreds to thousands of axons plus associated connective tissue and blood vessels that lies outside the brain and spinal cord. -Twelve pairs of cranial nerves emerge from the brain and thirty-one pairs of spinal nerves emerge from the spinal cord. - This is divided into the autonomic nervous system, the somatic nervous system, and the enteric nervous system. -The autonomic nervous system is further divided into the sympathetic nervous system and parasympathetic nervous system

feedback systems

The body can regulate its internal environment through many ____________ or feedback loops, which are a cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored, reevaluated, and so on. Each monitored variable, such as body temperature, blood pressure, or blood glucose level, is termed a controlled condition. Any disruption that changes a controlled condition is called a stimulus.

planar joint

The articulating surfaces of bones in a type of synovial joint called a _________________, are flat or slightly curved. These joints primarily permit back-and-forth and side-to- side movements between the flat surfaces of bones, but they may also rotate against one another. Many of these joints are biaxial, meaning that they permit movement in two axes. -Some examples of these are the intercarpal joints (between carpal bones at the wrist), intertarsal joints (between tarsal bones at the ankle), sternoclavicular joints (between the manubrium of the sternum and the clavicle), acromioclavicular joints (between the acromion of the scapula and the clavicle), sternocostal joints (between the sternum and ends of the costal cartilages at the tips of the second through seventh pairs of ribs), and vertebrocostal joints (between the heads and tubercles of ribs and transverse processes of thoracic vertebrae).

stratum basale

The deepest layer of the epidermis is the _______________, composed of a single row of cuboidal or columnar keratinocytes. Some cells in this layer are stem cells that undergo cell division to continually produce new keratinocytes. The nuclei of keratinocytes in the stratum basale are large, and their cytoplasm contains many ribosomes, a small Golgi complex, a few mitochondria, and some rough endoplasmic reticulum. The cytoskeleton within keratinocytes of this skin layer includes scattered intermediate filaments, called keratin intermediate filaments (tonofilaments). The keratin intermediate filaments form the tough protein keratin in its more superficial epidermal layers. Keratin protects the deeper layers from injury. Keratin intermediate filaments attach to desmosomes, which bind cells of this layer to each other and to the cells of the adjacent stratum spinosum, and to hemidesmosomes, which bind the keratinocytes to the basement membrane positioned between the epidermis and the dermis. Melanocytes and Merkel cells with their associated Merkel discs are scattered among the keratinocytes of the basal layer. This layer is also known as the stratum germinativum to indicate its role in forming new cells.

cytokinesis, cleavage furrow

The division of a cell's cytoplasm and organelles into two identical cells is called ______________. This process usually begins in late anaphase with the formation of a _______________, a slight indentation of the plasma membrane, and is completed after telophase.

photopigment

The first step in visual transduction is absorption of light by a ______________, a colored protein that undergoes structural changes when it absorbs light, in the outer segment of a photoreceptor.

cytosol

The fluid portion of cytoplasm that contains water, dissolved solutes, and suspended particles.

cones, rods

The photopigments are integral proteins in the plasma membrane of the outer segment. In _______ the plasma membrane is folded back and forth in a pleated fashion; in ______ the pleats pinch off from the plasma membrane to form discs. The outer segment of each rod contains a stack of about 1000 discs, piled up like coins inside a wrapper.

cell division, somatic cell division, reproductive cell division

The process by which cells reproduce themselves. What are the two types?

deep wound healing

___________________ occurs when an injury extends to the dermis and subcutaneous layer. Because multiple tissue layers must be repaired, the healing process is more complex than in epidermal wound healing. In addition, because scar tissue is formed, the healed tissue loses some of its normal function. __(same as above)__ occurs in four phases: an inflammatory phase, a migratory phase, a proliferative phase, and a maturation phase. -During the inflammatory phase, a blood clot forms in the wound and loosely unites the wound edges. As its name implies, this phase of deep wound healing involves inflammation, a vascular and cellular response that helps eliminate microbes, foreign material, and dying tissue in preparation for repair. The vasodilation and increased permeability of blood vessels associated with inflammation enhance delivery of helpful cells. These include phagocytic white blood cells called neutrophils; monocytes, which develop into macrophages that phagocytize microbes; and mesenchymal cells, which develop into fibroblasts. -In the migratory phase, the clot becomes a scab, and epithelial cells migrate beneath the scab to bridge the wound. Fibroblasts migrate along fibrin threads and begin synthesizing scar tissue (collagen fibers and glycoproteins), and damaged blood vessels begin to regrow. During this phase, the tissue filling the wound is called granulation tissue. -The proliferative phase is characterized by extensive growth of epithelial cells beneath the scab, deposition by fibroblasts of collagen fibers in random patterns, and continued growth of blood vessels. -Finally, during the maturation phase, the scab sloughs off once the epidermis has been restored to normal thickness. Collagen fibers become more organized, fibroblasts decrease in number, and blood ves- sels are restored to normal (Figure 5.6d). The process of scar tissue formation is called fibrosis. Some- times, so much scar tissue is formed during deep wound healing that a raised scar- one that is elevated above the normal epidermal surface results. If such a scar remains within the boundaries of the original wound, it is a hypertrophic scar. If it extends beyond the boundaries into normal surrounding tissues, it is a keloid scar, also called a cheloid scar. Scar tissue differs from normal skin in that its collagen fibers are more densely arranged, it has decreased elasticity, it has fewer blood vessels, and it may or may not contain the same number of hairs, skin glands, or sensory structures as undamaged skin. Because of the arrangement of collagen fibers and the scarcity of blood vessels, scars usually are lighter in color than normal skin.

fast glycolytic fibers

____________________ are largest in diameter and contain the most myofibrils. Hence, they can generate the most powerful contractions. -These fibers have low myoglobin content, relatively few blood capillaries, and few mitochondria, and appear white in color. -They contain large amounts of glycogen and generate ATP mainly by glycolysis. -Due to their large size and their ability to hydrolyze ATP rapidly, these fibers contract strongly and quickly. These fast-twitch fibers are adapted for intense anaerobic movements of short duration, such as weight lifting or throwing a ball, but they fatigue quickly. -Strength training programs that engage a person in activities requiring great strength for short times increase the size, strength, and glycogen content of these specific fibers. These fibers of a weight lifter may be 50% larger than those of a sedentary person or an endurance athlete because of increased synthesis of muscle proteins. The overall result is muscle enlargement due to hypertrophy of the these fibers.

hypotonic solution

a solution that has a lower concentration of solutes than the liquid inside the cell. In this case, water molecules enter the cells faster than they leave, causing the cell to swell.

somatic motor neurons

the neurons that stimulate skeletal muscle fibers to contract are called __________________. Each one has a threadlike axon that extends from the brain or spinal cord to a group of skeletal muscle fibers. A muscle fiber contracts in response to one or more action potentials propagating along its sarcolemma and through its system of T tubules.

epiphyses

the proximal and distal ends of the long bone.

substrate

the reactant molecules on which the enzyme acts

burns

tissue damage caused by excessive heat, electricity, radioac- tivity, or corrosive chemicals that denature (break down) proteins in the skin. These destroy some of the skin's important contributions to homeostasis—protection against microbial invasion and dehydration, and thermoregulation. They are graded according to their severity: -A first-degree burn involves only the epidermis. It is characterized by mild pain and erythema (redness) but no blisters. Skin functions remain intact. Immediate flushing with cold water may lessen the pain and damage caused by a first-degree burn. Generally, healing of a first-degree burn will occur in 3 to 6 days and may be accompanied by flaking or peeling. One example of a first-degree burn is mild sunburn. - A second-degree burn destroys the epidermis and part of the dermis. Some skin functions are lost. In a second- degree burn, redness, blister formation, edema, and pain result. In a blister the epidermis separates from the dermis due to the accumulation of tissue fluid between them. Associated structures, such as hair follicles, sebaceous glands, and sweat glands, usually are not injured. If there is no infection, second-degree burns heal without skin grafting in about 3 to 4 weeks, but scarring may result. First- and second-degree burns are collectively referred to as partial-thickness burns. -A third-degree burn or full-thickness burn destroys the epidermis, dermis, and subcutaneous layer. Most skin functions are lost. Such burns vary in appearance from marble-white to mahogany colored to charred, dry wounds. There is marked edema, and the burned region is numb because sensory nerve endings have been destroyed. Regeneration occurs slowly, and much granulation tissue forms before being covered by epithelium. Skin grafting may be required to promote healing and to minimize scarring.