Anatomy and Physiology Chapter 10

blood capillary

N

endomysium

O

Z line

1

creatine phosphate is fastest glycolysis is the second quickest aerobic cellular respiration is the slowest

Place the following in order from the slowest speed to the quickest speed: glycolysis, creatine phosphate hydrolysis, aerobic cellular respiration

b f a d e c

Place the sequence of events resulting in skeletal muscle contraction in order a. generation of a muscle action potential b. generation of a nerve impulse c. power stroke with actin and myosin binding and release d. release of calcium ions from the sarcoplasmic reticulum e. calcium ion binding to troponin f. release of the neurotransmitter acetylcholine

striations

Q

sarcoplasm

R

terminal cisterns of the sarcoplasmic reticulum

Release of calcium from these structures triggers skeletal muscle contraction.

sarcolemma

S

calcium ions and ATP

Skeletal muscle contraction will continue to occur as long as which chemicals are available in the cytosol of the muscle fiber?

perimysium

10

muscle fiber

11

sarcolemma

12

myofibril

13

13 myosin heads 14 thick filament

13 15

filament

14

I band

2

e) all of these choices are correct

2) The different types of muscle tissue differ from each other by a) microscopic anatomy. b) location. c) type of Control. d) both microscopic anatomy and location. e) All of these choices are correct.

thin filament (actin)

3

e) production of vitamins.

3) Which of the following is NOT a major function of muscle tissue? a) moving blood throughout the body b) generating heat through contractions c) stabilizing the movement of joints d) promoting movement of body structures e) production of vitamins.

1. Ca2+ flows out of the terminal cistern and binds to the troponin 2. the troponin changes conformation (shape) which pulls the tropomyosin 3. the change in conformation (shape) reveals an active binding site on the actin 4. myosin heads bind to the actin forming cross bridges which involves the hydrolysis of ATP 5. the release of the ADP causes the power stroke

4

bone

4

thick filament (myosin)

4

M line

5

The myosin power stroke results in the thin actin fibers moving towards the M line of the sarcomere causing the muscle length to shorten.

5

periosteum

5

A band

6

tendon

6

H zone

7

epimysium

7

belly of skeletal muscle

8

endomysium

9

fascicle

A

latent period

A

thin filament made of actin

A

twitch contraction

A brief contraction of all muscle fibers in a motor unit in response to a single action potential moving down the somatic motor neuron is known as

endoysium perimysium epimysium

A tendon is formed by the merging of the which structures?

1. convert the lactic acid produced during exercise back into glycogen. 2. resynthesize creatine phosphate. 3. replace oxygen displaced from muscle myoglobin.

After prolonged strenuous exercise has stopped, heavy breathing will often continue for several minutes in order to provide the oxygen needed to do what three things?

go through cell division

After the fusion of myoblasts, the muscle fiber loses its ability to do what?

muscular hypertrophy

An increase in the production of myofibrils, mitochondria, sarcoplasmic reticulum, and other organelles that usually occurs after birth

b) calcium ions

Smooth muscle tone is maintained by the prolonged presence of _____ in the muscle cell's cytosol? a) ATP b) calcium ions c) phosphate ions d) myoglobin e) None of these choices.

Typically, the different motor units of an entire muscle are not stimulated to contract in unison. Some are contracting and others are relaxing.

Are all the motor units in an entire muscle stimulated at the same time?

filament (thick or thin)

T

most skeletal muscles have all 3 fibers and usually half are SO, but this can vary depending on a persons training regimen

Are muscles composed of only one kind of muscle fiber?

contraction period

B

thick filament made of myosin

B

tropomyosin

B

Zone of overlap

The area covered by 6 minus the area covered by 5

myofibrils

The contractile organelles of a skeletal muscle fiber are thread-like structures called

dense bodies that are dispersed throughout the sarcoplasm some directly attach to the sarcolemma

There are no z discs in smooth muscle fibers. What do the filaments attach to?

slow oxidative fiber

This is the least powerful type of skeletal muscle fiber.

epimysium

This is the outermost layer of connective tissue surrounding a skeletal muscle.

synaptic cleft

To stimulate skeletal muscle contraction, acetylcholine must cross the _____ of the neuromuscular junction and bind to receptors on the motor endplate.

1. electrical excitability 2. contractility 3. extensity 4. elasticity

What are the four properties of muscular tissue?

hormones and neurotransmitters adjust heart rate by speeding or slowing the pacemaker

What can cause the heart rate to change and how does it affect the heart

1. it provides a way for nerve, blood, lymph to get the muscle. 2. triglycerides insulate and protect the muscle

What does the subcutaneous layer do for the muscles?

ATP hydrolysis reaction

What energizes the myosin head?

Calcium ions are continually released even though the calcium ions in the sarcoplasm are still elevated

What is happening in the sarcoplasm that is responsible for tetanus?

subcutaneous layer areolar and adipose

What layer separates muscle from skin? What type of tissue is that layer composed of?

From the M line to Z disc

What regions of a sarcomere contain titan?

tropomyosin and troponin

What regulatory proteins can be found in the thin filaments of skeletal muscle fibers?

epimysium

What structure holds muscles with similar functions together, allows free movement of muscles, carries nerves, blood vessels and lymphatic vessels, and fills spaces between muscles?

skeletal muscle fiber - acetylcholine released by somatic motor neurons cardiac muscle fiber - acetylcholine and norepinephrine released by autonomic motor neurons AND hormones smooth muscle fiber - acetylcholine and norepinephrine released by autonomic motor neurons AND hormones AND stretching AND local chemical changes

What things regulate the contraction of skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?

aponeurosis

What type of tendon is formed when the connective tissue elements of a skeletal muscle extend as a broad flat layer?

tension force

When a skeletal muscle contracts, it generates ________ while pulling on its attachment points. (force of contraction)

4

Which area of the myogram shows a sustained contraction where individual twitches are indiscernible?

2

Which area of the myogram shows sustained contraction with partial relaxation?

muscular atrophy

Which disorders is characterized by the wasting away of muscles due to the progressive loss of myofibrils?

c eccentric contraction

Which figure exhibits a contraction of the biceps brachii muscle in which its length increases? what is this called?

b

Which figure exhibits concentric contraction of the biceps brachii muscle?

a

Which figure exhibits isometric contraction of the biceps brachii muscle?

d) deepening of the voice

Which is a NOT a side-effect of anabolic steroid use by male athletes? a) sterility b) baldness c) diminished testosterone secretion d) deepening of the voice e) atrophy of testes

e) high amount of glycogen in the sarcoplasm

Which of following is a common characteristic of fast skeletal muscle fibers? a) large amount of myoglobin. b) many mitochondria. c) low concentration of creatine kinase in the sarcoplasm. d) slow myosin ATPase. e) high amount of glycogen in the sarcoplasm.

b) motor unit

Which of the following consists of a somatic motor neuron and all the skeletal muscle fibers it stimulates? a) sarcomere b) motor unit c) neuromuscular junction d) muscle unit e) multi-unit smooth muscle

d) axon of neuron, sarcolemma, T tubules

Which of the following correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction? a) sarcolemma, axon of neuron, T tubules b) T tubules, sarcolemma, myofilament c) muscle fiber, axon of neuron, myofibrils d) axon of neuron, sarcolemma, T tubules e) myofibrils, myofilaments, mitochondria

b) limited, under certain conditions

Which of the following describe the regeneration capacity of cardiac muscle cells? a) limited, via satellite cells b) limited, under certain conditions c) considerable (compared with other muscle cells, but limited compared with epithelium), via pericytes d) all of these are correct e) none of these are correct

b. myosin

Which of the following functions as a motor protein in all three types of muscle tissue? a) actin b) myosin c) troponin d) titan e) tropomyosin

e) all of these are correct

Which of the following is a common effect of aging on skeletal muscle? a) loss of muscle mass b) decrease in maximal strength c) a slowing of muscle reflexes d) loss of flexibility e) all of these are correct

e

Which of the following is not true concerning sarcomeres (before contraction begins) and the muscle fiber length-tension relationships a. if sarcomeres are stretched, the tension in the fiber decreases b. if a muscle cell is stretched so that there is no overlap of the filaments, no tension is generated c. extremely compressed sarcomeres result in less muscle tension d. maximum tension occurs when the zone of overlap between a thick and thin filament extends from the edge of the H zone to one end of a thick filament e. if sarcomeres shorten, the tension in them increases

d) Lactic acid is continually produced

Which of the following statements does NOT accurately describe aerobic cellular respiration in skeletal muscles? a) Pyruvic acid generated by glycolysis enters the mitochondria. b) O2 is essential. c) CO2 is produced as a waste product. d) Lactic acid is continually produced. e) Can be used to generate ATP from fats, proteins or carbohydrates.

tendon

Which of the following structures are made of dense regular connective tissue?

e) cramp

Which of the following types of abnormal contractions of skeletal muscle may be caused by holding a position for a prolonged period? a) spasm b) fasciculation c) tremor d) fibrillation e) cramp

a) cardiac muscle

Which of the following types of muscle tissue contract when excited by their own autorhythmic muscle fibers? a) cardiac muscle b) slow twitch oxidative skeletal muscle c) multi-unit smooth muscle d) fast twitch glycolytic skeletal muscle e) All of these choices are correct.

both I band and A band

Which of the regions of a sarcomere contain thin filaments?

A band, H band, and the zone of overlap

Which of the regions of the sarcomere contain thick filaments?

refractory period

Which period is referred to as the period of lost excitability in skeletal muscle fibers?

1

Which portion of this myogram shows a single twitch of the muscle?

d) all of these choices are correct

Which processes are commonly used to produce ATP during skeletal muscle contraction? a) creatine phosphate b) anaerobic cellular respiration c) aerobic cellular respiration d) All of these choices are correct. e) None of these choices are correct.

extensibility

Which property of muscle gives it the ability to stretch without damage?

dystrophin

Which proteins are used to reinforce the sarcolemma and to help transmit the tension generated by the sarcomeres to the tendons?

single-unit smooth muscle fibers

Which type of muscle tissue is capable of undergoing the stress-relaxation response when they are stretched?

I band

Z discs pass through the center of which band?

sarcolemma

a

somatic motor neuron axon terminal buton (bulb)

a

twitch contraction

a brief contraction of all the muscle fiber in a motor unit of a muscle in response to a single action potential in its motor neuron

fibromyalgia

a chronic, painful, nonarticular rheumatic disorder that affects he fibrous connective tissue components of muscles and ligaments

tendon

a cord of dense regular connective tissue that attaches muscle to the periosteum of a bone

fascia

a dense sheet of connective tissue that lines the body wall and binds muscles with similar functions together.

sarcoplasmic reticulum

a fluid-filled system of membranous sacs that encircle every myofibril

fasicles

a group of 10 to 100 muscle fibers surrounded by perimysium

Z disc

a narrow, plate-shaped region of dense protein that separates one sarcomere from the next

cramp

a painful spasmodic contraction

calmodulin

a regulatory protein that binds calcium in the cytosol of a smooth muscle cell

tremor

a rhythmic, involuntary, purposeless contraction that produces a quivering or shaking movement

anaerobic cellular respiration glucose is catabolized to generate ATP glycogen is catabolized to generate glucose

a series of ATP-producing reactions that do not require oxygen What molecules are used?

endomysium

a sheath of areolar connective tissue that wraps around individual skeletal muscle fibers

motor unit

a single somatic motor neuron and all the muscle fibers it stimulates

muscle tone

a small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units

stress-relaxation response

a smooth muscle phenomenon where smooth muscle fibers are stretched and it results in an initial contraction which increasing the tension but then in a minute or two it relaxes

tic

a spasmodic twitching made involuntarily by muscles that are ordinarily under voluntary control

fibrillation

a spontaneous contraction f a single muscle fiber that is not visible under the skin but can be recorded by electromyography

smooth muscle tone

a state of continued partial contraction

flaccid

a state of limpness in which muscle tone is lost

spasm

a sudden involuntary contraction of a single muscle in a large group of muscles

triad

a transverse tubule and the two terminal cisterns on either side of it

neuromuscular disease

abnormality of skeletal muscle function due to disease or damage of any part of a motor unit

satellite cells divide slowly and fuse with existing fibers to assist both in muscle growth and repair

after birth, how is muscle repair accomplished?

mesoderm

all muscles of the body are derived from this embryonic tissue

striations

alternating light and dark bands on muscle tissue

recovery oxygen uptake

amount of oxygen needed to restore the body's metabolic conditions back to resting levels after exercise

myasthnia gravis

an autoimmune disease that causes chronic, progressive damage of the neuromuscular junction

myosin light chain kinase

an enzyme in the cytosol of a smooth muscle cell that takes a phosphate from calmodulin and attaches it to the head of the myosin, enabling the head to attach to the actin

muscular hyperplasia

an increase in the number of muscle fibers, usually during embryonic development

fasciculation

an involuntary, brief twitch of an entire motor unit that is visible under the skin and is not associated with movement of the affected muscle

30 - 40 seconds of maximal muscle activity

anaerobic cellular respiration can provide enough energy for how many seconds of maximal muscle activity?

the weakest motor units are stimulated first

are the weaker or stronger motor units stimulated first?

I band

area in the sarcomere where only thin filaments are present but thick filaments are not

H zone

area of only thick filaments

subcutaneous layer

areolar and adipose connective tissue that separates muscle from skin

myofibril triad

b

sarcolemma

b

auto rhythmicity

built in rhythm

fascicles

bundles of muscle fibers

myofirbril

c

transverse tubule

c

calsequestrin

calcium binding proteins

rigor mortis

calcium ion leakage in a cadaver result in myosin to create cross bridges but no ATP is available to cause the myosin to release

M line

composed of supporting proteins holding thick filaments together at the H zone

aponeurosis

connective tissue elements extended as a broad, flat layer

myosin and actin

contractile motor proteins

actin

contractile protein that contains myosin-binding sites

sarcomere

contracting unit of a skeletal muscle fiber

eccentric isotonic contraction

contraction in which a muscle lengthens

isometric contraction

contraction in which muscle tension is generated without shortening the muscle

concentric isotonic contraction

contraction in which the muscle shortens

sarcoplasm

cytoplasm of a muscle fiber

sarcoplasm

cytoplasm of the muscle fiber

terminal cistern of the sarcoplasmic reticulum

d

sarcoplasm

d - substance in the spaces shown

A band the band is the entire length of the thick filaments

darker middle part of the sarcomere this is the length of what structure?

hypotonia

decreased or lost muscle tone

fascia

dense irregular connective tissue that lines the body wall and limbs and holds functional muscle units together

perimysium

dense irregular connective tissue that separates a muscle into groups of individual muscle fibers

perimysium

dense irregular tissue that surrounds groups of 10 to 100 muscle fibers

1. largest in diameter with the most myofibrils 2. most powerful 3. white muscle fibers 4. fastest contraction cycle 5. quickest to reach peak tension 6. fatigue quickly 7. anaerobic glycolysis (they have lots of stored glycogen)

describe fast glycolytic fibers 1. diameter 2. power generated 3. color 4. contraction cycle speed 5. time to peak tension 6. stamina 7. major ATP production used

1. intermediate in diameter 2. medium in power 3. red muscle fibers 4. contraction cycle 3 - 5 times factor than SO fibers 5. reach peak tension more quickly, but shorter in duration than the SO fibers 6. moderately high resistance to fatigue 7. aerobic cellular respiration and anaerobic glycolysis

describe fast oxidative-glycolytic fibers 1. diameter 2. power generated 3. color 4. contraction cycle speed 5. time to peak tension 6. stamina 7. major ATP production used

1. smallest in diameter 2. least powerful 3. red muscle fibers 4. slower contraction cycle 5. longer to reach peak tension 6. very resistant to fatigue 7. uses most aerobic cellular respiration to make ATP

describe slow oxidative fibers 1. diameter 2. power generated 3. color 4. contraction cycle speed 5. time to peak tension 6. stamina 7. major ATP production used

it rotates as a corkscrew turn, twisting in a helix

describe the movement of the smooth muscle fiber as it contracts

terminal cisterns

dilated ends of sarcoplasmic reticulum

myopathy

disease or disorder of the muscle cell itself

skeletal muscle fiber - no cardiac muscle fiber - yes smooth muscle fiber - yes

do skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber have autorhythmicity?

skeletal muscle fiber - yes cardiac muscle fiber - yes smooth muscle fiber - no

do skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber have sarcomeres?

skeletal muscle fiber - abundant cardiac muscle fiber - some smooth muscle fiber - very little

do skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber have sarcoplasmic reticulum?

skeletal muscle fiber - none cardiac muscle - intercalated discs contain gap junctions and desmosomes visceral smooth muscle - gap junctions multiunit smooth muscle - none

do skeletal muscle fiber, cardiac muscle, visceral smooth muscle, and multiunit smooth muscle have junctions?

contracted, because the zone of overlap is wide and the H zone is narrow

do you think this myofibril is contracted or relaxed? Why?

eccentric isotonic contractions like walking downhill produce more muscle damage and more delayed-onset muscle soreness than do concentric isotonic contractions

does concentric or eccentric isotonic contraction produce more muscle damage and soreness?

every action potential has the same size in a somatic motor neuron or a muscle fiber

does the strength of action potentials vary?

actin thin filament

e

sarcoplasmic reticulum

e

muscle action potentials

electrical signals in a muscle

when a second stimulus occurs after the refractory period of the the first stimulus is over, but before the skeletal muscle fiber has relaxed, the second contraction will actually be stronger than the first.

explain wave summation

myosin thick filament

f

transverse tubule

f

central fatigue

feeling of tiredness and the desire to cease activity

tension

force of contraction

hypertrophy

growth by enlargement of the muscle cells

hyperplasia

growth by increase in the number of muscle cells

anabolic steroids

hormones that increase muscle size by increasing the synthesis of proteins in muscles and thus increasing strength during athletic contests

Muscle fibers switch from using low levels of ATP when relaxed to requiring large amounts of ATP when contracting. Most other cells have a constant amount of ATP usage.

how are the energy requirements different for muscle cells than for the majority of the other cells

the muscle filaments are not arranged in orderly sarcomeres and there is no regular pattern of overlap like in the striated muscle there are also intermediate filaments in addition to the thick and tin filaments

how are the filament arrangements in smooth muscle different than those in striated muscles?

cardiac muscle does not have an epimysium

how are the tissue layers in cardiac muscle tissues different than the tissue layers in skeletal muscle tissues?

increase the size of the muscle fibers

how do growth hormones and sex hormones affect muscle cells?

elastic components are not given time to spring back between contractions, and thus remain taut. Therefore, they do not need to stretch much before the next contraction

how do the elastic components add to the effect of tetanus?

the number and size of mitochondria is much greater in cardiac muscle aerobic cellular respiration is the primary source of ATP in a cardiac muscle fiber making the heart dependent on oxygen

how do the number and size of mitochondria in cardiac muscle compare to skeletal muscle mitochondria? what does this tell you about the cardiac muscle fibers?

creatine kinase transfers a high energy phosphate from ATP to creatine

how i creatine phosphate created?

cardiac muscle remains contracted 10 to 15 times longer than skeletal muscle Calcium ions enter the sarcoplasm from the interstitial fluid through channels as well as from the sarcoplasmic reticulum allowing for longer contraction

how is the contraction time in cardiac muscle different than the contraction time in skeletal muscle? what accounts for this?

2 ATP

how many ATP are produced by glycolysis?

larynx 2 - 3 muscle fibers per motor unit eye muscles 10 - 20 muscle fibers per unit biceps brachii in the arm 2,000 - 3,0000 muscle fibers per unit

how many muscle fibers per unit are in the following muscles: larynx eye muscles biceps brachii

one

how many possible neuromuscular junctions are possible for a single skeletal muscle fiber?

an average of 150

how many possible neuromuscular junctions are possible for a single somatic motor neuron axon?

75 times per minute

how often does cardiac muscle tissue contract when the body is at rest?

aerobic cellular respiration

in marathons, almost 100% of the ATP is produced by this method

smooth muscle fibers

in this type of muscle fiber, contraction begins slowly but lasts for long periods

smooth muscle

in this type of muscle fiber, thick and thin filaments are not arranged as orderly sarcomeres

muscle fatigue

inability of a muscle to maintain its strength of contraction or tension during prolonged activity

spasticity

increased in muscle tone associated with an increase in tendon reflexes

hypertonia

increased muscle tone

rigidity

increased muscle tone in which reflexes are not affected causing stiffness and spasms

endomysium

individual muscle fibers are covered by this layer.

muscular dystrophy

inherited muscle-destroying disease that causes progressive degeneration of the skeletal muscle fibers

transverse tubules

invaginations of the sarcolemma from the surface toward the center of the muscle fiber

wave summation

larger contractions resulting from stimuli arriving at different times

I band the band is the length of the thin filaments that do NOT lie in between the thick filaments (subtract the zone of overlap)

lighter, less dense area on the ends of the sarcomere this is the length of what structure?

neuromuscular junction (NMJ)

location where neuron action potentials are converted to muscle action potentials

flaccid paralysis

loss of muscle tone, tendon reflexes, and atrophy/degeneration of muscles due to nervous system and electrolyte disruptions

A band

middle area in the sarcomere where thick and thin filaments are found

muscle fiber

muscle cell

a few seconds

muscle cells have enough ATP stored within them to last only __________________.

concentric isotonic contraction

muscle contraction in which the tension generated is great enough to overcome the resistance of the object to be moved, the muscle shortens and pulls on a tendon, producing movement and decreasing the angle of a joint

isotonic contraction

muscle contraction in which the tension in the muscle remains almost constant while the muscle changes its length

satellite cells

myoblasts that persist in mature skeletal muscle

satellite cells

myoblasts that persist in skeletal muscle fibers after they have fused

titin alpha-actinin myomesin nebulin dystrophin

name the five structural proteins found in a myofibril.

myosin and actin

name the two contractile proteins

H zone the band is the length of the thick filaments that do NOT lie between thin filaments (subtract the zone of overlap)

narrow zone in the center of each A band this is the length of what structure?

the frequency of stimulation

number of action potential impulses per second

myoglobin

oxygen storing protein only found in muscle

myoglobin

oxygen-binding protein found only in muscle fibers

spastic paralysis

partial paralysis in which the muscle exhibits an increase in muscle tone due to nervous system and electrolyte disruptions

sarcolemma

plasma membrane of a muscle fiber

motor unit recruitment

process of increasing the number of activated motor units

M line

region in the center of the H zone that contains proteins that hold thick filaments together at the center of the sarcomere

tropomyosin

regulatory protein that blocks myosin-binding sites

more ATP creatine phosphate

resting muscle cells create _____________ than they use. Most of this is stored as ______________.

endomysium

reticular tissue that penetrates the fascicle and separates individual muscle fibers from one another

Z disc

separates the sarcomeres from each other

red muscle fibers

skeletal muscle cells with a high myoglobin content, many capillaries, and many mitochondria

white muscle fibers

skeletal muscle cells with a low myoglobin content, low number of capillaries, and smaller number of mitochondria

pericytes

stem cells capable of differentiating into smooth muscle cells

1. Nerve impulse arrives at the axon terminal 2. Ca2+ ion channels open 3. Ca2+ flows into cell 4. triggers release of acetylcholine (ACh) by vesicles into the synaptic cleft

step 1

1. ACh binds to receptors in the motor plate junctional folds causing Na+ to flow into the cell 2. the change in gradient triggers a muscle action potential that travels along the sarcolemma

step 2

1. the action potential travels to the terminal tubule 2. the changes in the terminal tubule causes the two terminal cistern in the triad to release Ca2+ ions into the myofiber (muscle cell)

step 3

fused (complete) tetanus

sustained contraction of a muscle, with no relaxation between stimuli

unfused (incomplete) tetanus

sustained, but wavering contraction with partial relaxation between stimuli

neuromuscular junction

synapse between a motor neuron and a muscle fiber

contractility

the ability to contract forcefully when stimulated by an action potential

electrical excitability

the ability to respond to certain stimuli by producing electrical signals

elasticity

the ability to return to its original length and shape after contraction or extension

extensibility

the ability to stretch within limits without being damaged

oxygen debt

the added oxygen, over and above the resting oxygen consumption, that is taken into the body after exercise

sarcomere

the basic functional unit of a myofibril

glycolysis

the breakdown of glucose to two molecules of pyretic acid

cardiac muscle fibers

the contractile cells of the heart

aponeurosis

the epimysium, perimysium, and endomysium together form this broad, flat, sheet extending beyond the muscle

tendon

the epimysium, perimysium, and endomysium together form this rope-like extension extending beyond the muscle

excitation-contraction coupling

the events where action potentials are linked to muscle contraction are called

muscle fatigue

the inability of a muscle to maintain force of contraction after prolonged activity

calsequestrin

the molecule that attaches to Ca2+ in the sarcoplasmic reticulum that allows for increasing storage of ions in the terminal cistern

epimysium

the outermost connective tissue layer that encircles an entire skeletal muscle

epimysium

the outermost layer of dense, irregular connective tissue that encircles the entire muscle

sarcolemma

the plasma membrane of the skeletal muscle cell

cardiac muscle tissue

the principle muscle tissue in the heart wall

motor unit recruitment

the process in which the number of active motor units increase

strength training

the process of exercising with progressively heavier resistance for the purpose of strengthening the musculoskeletal system

stress-relaxation response

the smooth muscle action that allows the fibers to maintain their contractile function, even when stretched

acetylcholine

the synaptic end bulbs of the somatic motor neurons contain synaptic vesicles filled with the neurotransmitter ___________.

eccentric isotonic contraction

the tension exerted by the muscle fiber resists the movement of a load and slows the lengthening process

isometric contraction

the tension generated by this type of contraction is not enough to exceed the resistance of the object to be moved, and the muscle does not change its length

muscular atrophy fibrosis

the wasting away of muscle due to lack of use is known as __________ while the replacement of skeletal muscle fibers with scar tissue is known as ___________.

Damaged muscle undergoes fibrosis, the replacement of muscle fiber with fibrous scar tissue

there is a limited number of satellite cells and this means only a small amount of muscle can be repaired. What happens with the rest of damaged muscle?

myogram

these diagrams are all what kind of graph?

mitochondria

these organelles are in large amounts in the muscle fiber and lie close to the contractile filaments

muscle tone

this type of contraction is produced by the continual involuntary activation of a small number of skeletal muscle motor units; results in firmness in skeletal muscle

cardiac muscle fiber and smooth muscle fiber

this type of muscle fiber can be autorhythmic

smooth muscle fiber

this type of muscle fiber can be classified as a single-unit or multi-unit

skeletal fiber

this type of muscle fiber does not exhibit autorhythmicity

cardiac muscle fiber

this type of muscle fiber has an extended contraction due to prolonged calcium delivery from both the sarcoplasmic reticulum and the interstitial fluid

cardiac muscle

this type of muscle fiber has fibers joined by intercalated discs

skeletal and cardiac muscle fibers

this type of muscle fiber is striated

smooth muscle fiber

this type of muscle fiber uses pericytes to repair damaged muscle fibers

skeletal and cardiac muscle fibers

this type of muscle fiber uses troponin as a regulatory protein

smooth muscle fiber

this type of muscle fiber uses calmodulin as a regulatory protein

skeletal muscle fiber

this type of muscle fiber uses satellite cells to repair damaged muscle fibers

delayed onset muscle soreness

this type of problem involves the swelling and stiffness resulting from increase in muscle protein synthesis, increased blood supply, and increased creation kinase production after strenuous exercise

exercised induced muscle damage

this type of problem involves torn sarcolemmas, damaged myofibrils, and disrupted Z disc

tranverse tubule (T tubule)

tiny invaginations of the sarcolemma that form tunnels towards the center of the muscle fiber

myofibril

tiny threadlike contractile organelles in the muscle fiber cells

true

true or false the ability of muscle cells to respond to stimuli and produce electrical signals is known as excitability

tendon sheath (synovial sheath)

two-layer tube of fibrous connective tissue enclosing certain tendons

titin

very large intersarcoplasmic protein that gives elasticity to the sarcomere

gap junctions

visceral (single unit) smooth muscle tissue uses what kind of junctions?

muscular atrophy

wasting away of muscles

disuse atrophy

wasting away of muscles due to inactivity

denervation atrophy

wasting away of muscles due to severing the nerve supply

calcium diffuses slowly into and out of a smooth muscle fiber this is necessary for places like the walls of arteries or parts of the digestive tracts where a constant, steady pressure is necessary

what accounts for the ability of smooth muscle to maintain smooth muscle tone? why would this ability be important for smooth muscles?

hypertrophy of the FG fibers and an increase in the synthesis of muscle proteins (the number of muscle cells does not increase)

what accounts for the large size and mass of muscles of body builders?

mesodermal stem cells become myoblast

what are the embryonic cells that differentiates into a mature skeletal fiber?

ATP carbon dioxide heat

what are the final products of aerobic cellular respiration?

1. producing body movements 2. stabilizing body position 3. storing and moving substances within the body 4. generating heat

what are the four functions of muscular tissue

skeletal muscle fiber - troponin and tropomyosin cardiac muscle fiber - troponin and tropomyosin smooth muscle fiber - calmodulin and myosin light chain kinase

what are the regulatory proteins in skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?

skeletal muscle fiber - fast cardiac muscle fiber - moderate smooth muscle fiber - slow

what are the speeds of contraction for skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?

1. creatine phosphate 2. anaerobic cellular respiration 3. aerobic cellular respiration

what are the three methods a muscle fiber can use to generate ATP?

slow oxidative fibers fast oxidative-glycolytic fibers fast glycolytic fibers

what are the three types of muscle cells based on the speed of the hydrolysis of ATP by the myosin heads

skeletal smooth cardiac

what are the three types of muscle tissue?

1. convert lactic acid back into glycogen stores in the liver 2. resynthesize creatine phosphate 3. replace oxygen removed from myoglobin

what are the three uses for the oxygen that is taken back up after exercise has ceased?

1. contraction in a smooth muscle fiber starts more slowly and lasts longer than skeletal contraction 2. smooth muscle can both shorten and stretch to a greater extent than the other muscle types

what are the two differences in contraction in a smooth muscle compared to a skeletal muscle?

autorhythmic electrical signals chemical stimuli - neurotransmitters, hormones, change in pH

what are the two main types of stimuli that can stimulate an muscle action potential

tropomyosin and troponin

what are the two regulatory proteins found in a myofibril?

1. oxygen that diffuses into muscle from the blood 2. oxygen that is released by myoglobin within muscle fibers

what are the two sources of oxygen for a muscle cell?

isotonic contraction isometric contraction

what are the two types of contraction?

concentric isotonic contraction eccentric isotonic contraction

what are the two types of isotonic contraction?

visceral (single unit) smooth muscle tissue multi-unit smooth muscle tissue

what are the two types of smooth muscle tissue?

glycogen

what carbohydrate is found in large concentrations in the sarcoplasm?

irregular transverse thickening of the sarcolemma that connect the ends of cardiac muscle fibers to one another

what creates the intercalated discs in heart muscle?

the percentage of SO and FG fibers is genetically determined and might account for the differences in activities preferred by different people exercise can also cause the transformation of one kind of fiber to another

what determines the ratio of SO and FG fibers for a person's muscles?

links thin filaments of the sarcomere to the integral membrane proteins of the sarcolemma, which are attached to proteins in the connective tissue extracellular matrix that surrounds the muscle fibers.

what does dystrophin do for a muscle fiber?

1. amount of stretch before contraction 2. oxygen availability 3. number of muscle fibers contracting in unison 4. frequency of stimulation

what four things affect the strength of a muscle contraction?

pyruvic acid is converted into lactic acid which diffuses out into the blood

what happens to the products of glycolysis if there i no oxygen available?

Na+

what ion enters the sarcoplasm when the acetylcholine attaches to the receptors in the motor end plate junctional folds?

Ca2+

what ion enters through a voltage gated channel when the action potential arrives at the terminal buton

a somatic motor neuron and all of the muscle fibers it stimulates

what is a motor unit?

satellite cells retain the capacity to fuse with one another or damaged muscle to repair tissue.

what is special about the satellite cells in a muscle?

multiunit smooth muscle tissue consists of individual fibers each with its own motor neuron terminal and few gap junctions visceral (single unit) smooth muscle tissue consists of numerous fibers connected to each other through gap junctions with a single neuron synapsing with several of the fibers. Some of the fibers do not have neuromuscular junctions

what is the difference between the enervation and junctions found in visceral (single unit) smooth muscle and multiunit smooth muscle tissue?

acetylcholinesterase AChE

what is the enzyme that degrades acetylcholine in the synaptic cleft?

posture endurance-type activities like a marathon

what is the function of slow oxidative fibers?

anything that requires great strength for short times, like weight lifting

what is the function of the fast glycolytic fibers?

activities like walking and sprinting

what is the function of the fast oxidative-glycolytic fibers?

acetylcholine

what is the neurotransmitter used at the neuromuscular junction?

diameter 10 - 100 micrometers length 10 centimeters (4 inch) - 30 centimeters

what is the size of a mature skeletal muscle fiber (cell)?

8 nm and 1 - 2 micrometers long 16 nm and 1 - 2 micrometers long

what is the size of the thin actin filaments? what is the size of the thick myosin filaments?

desmosomes and gap junctions

what kind of junctions can be found in the intercalated discs in the heart muscle?

auto-rhythmicity

what kind of stimulation is used in visceral (single unit) smooth muscle tissue?

pyruvic acid

what molecule is used for aerobic cellular respiration?

ACT must bind again to the myosin head for it to release

what must happen to cause the myosin to break its cross-bridge to actin?

it is very elastic and can stretch to 4 times its length

what property of titan makes it useful for connecting the z disc to the M line

caveolae these are pouchlike invaginations of the plasma membrane that store calcium ions

what replaces transverse tubules and terminal cisternae in smooth muscles?

transverse T tubules

what structure spreads the muscle action potential throughout the muscle fiber

the autonomic nervous system

what subdivision of the nervous system controls the involuntary muscle

contractile protein structural protein regulatory protein

what three types of protein are used in the construction of a myofibril?

connective tissue

what tissue within the muscle limits the range of extensibility?

The H band and the zone of overlap

what two areas are in the A band?

facilitated diffusion

what type of transport is used to get glucose into the muscle cells?

the myosin heads would be unable to detach from the actin

what would happen if ATP were suddenly unavailable after the sarcomere had begun to shorten

refractory period

when a muscle fiber receives enough stimulation to contract, it temporarily loses its excitability. What is the name for this period of lost excitability?

unfused tetanus

when a skeletal muscle fiber is stimulated at a rate of 20 to 30 times per second and can only partially relax between stimuli

fused (complete) tetanus 5 - 10 times stronger

when a skeletal muscle fiber is stimulated at a rate of 80 to 100 times per second and it does not relax at all. Individual twitches cannot be detected How much stronger is this than a single twitch?

it makes up the protein in the z discs it binds the thin filaments

where can you find alpha actinin in the myofibril? what is its function?

most of the heart wall

where can you find cardiac muscle

walls of large arteries airways to the lungs arrector pili iris ciliary body of the eye

where can you find multiunit smooth muscle tissue?

muscles in the heart and muscles in the gastrointestinal tract

where can you find muscles that have autorhythmicity

wrapped around the entire length of each thin filament it anchors the thin filaments to Z discs

where can you find nebulin in the myofibril? What is its function?

it makes up the m line myosin binds to titn and connects adjacent filaments to one another myosin also holds the thick filaments together at the M line

where can you find the myosin in the myofibril? what is its function?

walls of hollow internal structures and most organs in the abdominopelvic cavity

where do you find smooth muscle in the human body

skin, walls of small arteries and veins, walls of hollow organs

where do you find visceral (single unit) smooth muscle tissue?

mitochondria

where does aerobic cellular respiration occur?

in the cytosol

where does glycolysis take place?

creatine is synthesized in the liver, kidneys, pancreas

where is creatine synthesized?

skeletal muscle fiber - sarcoplasmic reticulum cardiac muscle fiber - sarcoplasmic reticulum and interstitial fluid smooth muscle fiber - sarcoplasmic reticulum and interstitial fluid

where is the source of calcium for skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?

thin filaments

which filaments are attached to the z discs?

creatine phosphate is 3 - 6 times more plentiful than ATP in resting muscle cell

which is more prevalent in a resting muscle cell, creatine phosphate or ATP?

acetylcholine

which of the following are not sources of ATP for muscle contraction? creatine phosphate glycolysis anaerobic cellular respiration aerobic cellular respiration acetylcholine

hyperplasia

which type of muscle growth primarily occurs in an embryo?

smooth muscle, especially in your digestive tract

which type of muscle tissue undergoes the greatest amount extension?

smooth muscular tissue

which type of muscular tissue has the highest capacity for regeneration?

skeletal muscle fiber - somatic nervous system (voluntary) cardiac muscle fiber - autonomic nervous system (involuntary) smooth muscle fiber - autonomic nervous system (involuntary)

which type of nervous system controls skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?

oxygen is used for more than just the ATP pathways because of the increased temperature and increased blood pressure, tissue repair, and other factors

why do some people prefer the term recovery oxygen uptake to oxygen debt?

it has a huge size - 50 times larger than average protein It connects the Z disc to the M line of the sarcomere, allows the sarcomere to return to its original length, and keeps the A line in its position

why is titan protein named "titan?" what is the function of the titan protein?

relaxation period

C

troponin

C

z line

C

sarcoplasmic reticulum

Calcium ion storing tubular system similar to the smooth endoplasmic reticulum

a) at the beginning of a contraction

Calcium ions are released from the sarcoplasmic reticulum into the cytosol a) at the beginning of a contraction. b) in response to acetylcholine binding to Ca2+ release channels. c) by active transport using Ca2+ pumps in the SR membrane. d) after the contraction ends. e) All of these answers are correct.

skeletal muscle fiber - very large cardiac muscle fiber - large smooth muscle fiber - small

Compare the diameter of the muscle fibers in smooth, cardiac, and skeletal muscle tissue.

myosin head actin binding site

Cross bridges are formed during muscle contraction when _____ on the thick filaments binds to _____ on the thin filaments.

sarcomere

D

the actin binding site

D (the yellow dot)

Inadequate release of calcium ions from the SR, resulting in a decline of Ca2+ concentration in the sarcoplasm. Depletion of creatine phosphate also is associated with fatigue. Other factors that contribute to muscle fatigue include insufficient oxygen, depletion of glycogen and other nutrients, buildup of lactic acid and ADP, and failure of action potentials in the motor neuron to release enough acetylcholine.

Describe the factors that lead to muscle fatigue.

muscle fiber elongated shape

Each of our skeletal muscles is a separate organ composed of hundreds to thousands of cells, which are called _____________ because of their ________.

If the sarcomere is too stretched the myosin and actin fibers do not overlap enough to contract If the sarcomere is too contracted the myosin threads are compressed against the z discs and they cannot contract there is an optimal length of overlap that allows the best contraction, which is the usual condition of most sarcomeres. This is about 2.2 micrometers

Explain the length-tension relationship

perimysium

F

holding a book in your outstretched

Give an example of a muscle that is producing tension but not shortening.

skeletal muscle fiber - limited via satellite cells cardiac muscle fiber - limited and only under certain conditions smooth muscle fiber - considerable via pericytes

Give the capacity for generation and cells involved in muscle cell regeneration for skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber.

muscle fiber (cell)

H

A nerve impulse reaches the synaptic end bulb and causes the release of acetylcholine, which diffuses across the synaptic cleft and binds to and activates acetylcholine receptors on the motor end plate. Binding of acetylcholine opens an ion channel in the acetylcholine receptors allowing Na+ to flow into the cell, which generates an action potential in the muscle cell.

How does a nerve impulse elicit a muscle action potential?

2 ATP from glycolysis 36 ATP from aerobic cellular respiration

How many ATP are produced by glycolysis? How many ATP are produced by aerobic cellular respiration?

rapid destruction of ACh in the synaptic cleft by acetylcholinesterase.

In a neuromuscular junction, the effect of acetylcholine (ACh) binding to receptors on the motor end plate lasts only briefly due to _____________.

myosin head

In a sarcomere, which structure contains motor proteins that convert the energy in ATP into mechanical movements?

lengthen

In an isometric contraction the muscle develops tension but does not ____________.

e. a brief delay that occurs between application of a stimulus and the beginning of contraction

In muscle physiology, the latent period refers to a. the period of lost excitability that occurs when two stimuli are applied immediately one after the other b. the brief contraction of a motor unit c. the period of elevated oxygen use after exercise d. an inability of a muscle to contract forcefully after prolonged activity e. a brief delay that occurs between application of a stimulus and the beginning of contraction

15 seconds

In skeletal muscles, the combined amounts of creatine phosphate and ATP provide enough energy for the muscle to contract maximally for approximately how long?

5

In the diagram, where would you find stored Ca2+?

Titan

In the diagram, which structure helps return a stretched sarcomere to its resting length?

8 actin

In the diagram, which structure(s) moves towards the center of the sarcomere (closer together) when the fiber contracts?

motor unit recruitment

Increasing the number of active motor units within a skeletal muscle is called

myofibril (a stack of sarcomere)

K

endomysium

L

1. ATP hydrolysis 2. Attachment of myosin to actin forming cross bridges 3. The power stroke, then detachment of myosin from actin 4. The cycle will continue as long as ATP and calcium ions are available.

List the four steps of the contraction cycle in order of occurrence. What is needed for these steps to continuously repeat?

skeletal is voluntary and controlled by the brain smooth is involuntary and controlled by the brain cardiac is involuntary and controlled by a pacemaker inside the heart itself

List the three types of muscles and indicate whether they are voluntary or involuntary and what is the major locus of control.

motor neuron

M

d. all of these answers are correct

Myofibrils contain a) contractile proteins. b) regulatory proteins. c) structural proteins. d) all of these answers are correct. e) none of these answers are correct.

c

During muscle contraction all of the following occur except a. cross-bridges are formed when the energized myosin head attaches to actin's myosin-binding site b. ATP undergoes hydrolysis c. the thick filaments slide inward toward the M line d. calcium concentration in the cytosol increases e. the Z discs are drawn toward each other

M line

During muscle contraction by the sliding filament mechanism, thin filaments are pulled towards the __________.

latent period

During which period of a twitch contraction does the muscle action potential move along the sarcolemma of the muscle cell and trigger calcium release into the sarcoplasm?

myofibril organelle

E

nucleus

P