Deck 10: Muscle Tissue Physiology

Question 1

What anchors thin and elastic filaments in place within the myofibril?

A)M line
B)A band
C)Z disc
D)I band

Answer 1

C

Question 2

Which of the following statements is the most accurate description of the sliding filament mechanism?

A)Z discs slide over the thick and thin filaments.
B)Thin filaments slide past thick filaments towards the M line.
C)Thick filaments shorten while thin filaments remain unchanged.
D)Both thick and thin filaments shorten.

Answer 2

B

Question 3

A triad consists of:

A)a fascicle of skeletal muscle cells and its surrounding perimysium.
B)myosin filaments,myosin heads,and myosin tails.
C)actin filaments,troponin,and tropomyosin.
D)a transverse tubule (T-tubule)and two terminal cisternae.

Answer 3

D

Question 4

Where should most of the potassium ions be located when a muscle cell is at rest?

A)sarcoplasmic reticulum
B)transverse tubules (T-tubules)
C)extracellular fluid
D)cytosol of the muscle cell

Question 5

The Na⁺/K⁺ pump helps a muscle cell maintain a state of:

A)action potential.
B)propagation.
C)depolarization.
D)resting membrane potential.

Question 6

Which of the following wraps and surrounds an individual skeletal muscle fiber?

A)endomysium
B)epimysium
C)sarcoplasmic reticulum
D)perimysium

Question 7

The central region of the A band that lacks thin filaments is the:

A)H zone.
B)Z disc.
C)I band.
D)sarcomere.

Question 8

The degree to which a muscle cell can stretch depends on its:

A)distensibility.
B)contractility.
C)conductivity.
D)excitability.

Question 9

The storage and release of calcium ions is the key function of the:

A)sarcoplasmic reticulum.
B)sarcoplasm.
C)mitochondrion.
D)sarcolemma.

Question 10

Which of the following is descriptive of skeletal muscle fibers?

A)Skeletal muscle fibers lack a sarcolemma and myofibrils.
B)Skeletal muscle fibers are striated.
C)Skeletal muscle fibers are smaller than most cells.
D)Skeletal muscle fibers are uninucleate.

Question 11

What is the basic function of all muscle tissue?

A)regulate body temperature
B)stabilize joints
C)produce voluntary contractions
D)generate muscle tension

Question 12

Deep inward extensions of the sarcolemma form a tunnel-like network inside the muscle cell known as:

A)myofibrils.
B)the sarcoplasmic reticulum.
C)transverse tubules (T-tubules).
D)myofilaments.

Question 13

What is the functional contractile unit of the myofibril where muscle tension is produced?

A)sarcomere
B)A band
C)sarcolemma
D)I band

Question 14

Muscle contraction can occur when:

A)myosin filaments shorten.
B)I bands remain unchanged.
C)sarcomeres shorten.
D)A bands lengthen.

Question 15

The plasma membrane of a muscle cell is known as the:

A)myofibril.
B)sarcoplasmic reticulum.
C)sarcomere.
D)sarcolemma.

Question 16

When a skeletal muscle fiber contracts:

A)the H zone narrows while the I bands widen.
B)the A bands shorten while the I bands lengthen.
C)Z discs move farther apart while the A bands shorten.
D)the H zone and I bands narrow.

Question 17

What characteristic is NOT descriptive of cardiac muscle tissue?

A)voluntary muscle contractions
B)located in the heart
C)intercalated discs
D)striations

Question 18

Which protein does NOT belong in a thin filament?

A)troponin
B)myosin
C)tropomyosin
D)actin

Question 19

A muscle cell experiencing resting membrane potential is:

A)experiencing depolarization.
B)propagating an action potential.
C)polarized.
D)more negatively charged on its exterior than in its interior.

Question 20

What do skeletal muscle tissue and cardiac muscle tissue share in common?

A)Both skeletal and cardiac muscle tissues possess intercalated discs.
B)Both skeletal and cardiac muscle tissues are voluntary.
C)Both skeletal and cardiac muscle tissues perform peristalsis.
D)Both skeletal and cardiac muscle tissues consist of striated muscle cells.

Question 21

Between the start of the latent period and the start of the contraction period,there is a time interval during which the muscle cannot respond to another stimulus.This brief period is known as the:

A)refractory period.
B)tension period.
C)action potential.
D)relaxation period.

Question 22

What are possible products of glycolytic,or anaerobic,catabolism?

A)glucose only
B)ATP,pyruvate,and lactic acid
C)creatine phosphate only
D)oxygen only

Question 23

The synapse of a motor neuron with a muscle fiber is known as the:

A)neuromuscular junction.
B)synaptic bulb.
C)synaptic cleft.
D)motor end plate.

Question 24

Where are receptors for acetylcholine located?

A)sarcomere
B)triad
C)motor end plate
D)axon terminal

Question 25

Through which ATP-generating mechanism can long-lasting muscle contractions be sustained?

A)glycolysis
B)creatine phosphate reaction
C)anaerobic catabolism
D)oxidative catabolism

Question 26

Once excitation-contraction coupling has occurred,calcium ion concentration increases dramatically in the:

A)cytosol of the muscle fiber.
B)sarcoplasmic reticulum.
C)terminal cisterna.
D)sarcolemma.

Question 27

What does the depolarization of the transverse tubules (T-tubules)promote?

A)release of calcium from the sarcoplasmic reticulum
B)entry of sodium ions into the muscle fiber through voltage-gated sodium ion channels
C)release of acetylcholine from vesicles in the motor neuron into the synaptic cleft
D)binding of acetylcholine to ligand-gated sodium ion channels

Question 28

During muscle contraction,myosin crossbridges bind to active sites on:

A)T-tubules.
B)tropomyosin.
C)troponin.
D)actin.

Question 29

A pathway of ATP production that results in the formation of lactic acid is:

A)glycolytic catabolism.
B)oxidative catabolism.
C)anabolism.
D)aerobic catabolism.

Question 30

Which statement best describes the function of myoglobin?

A)Myoglobin is a source of ATP for muscles.
B)Myoglobin hydrolyzes ATP.
C)Myoglobin catabolizes glycogen.
D)Myoglobin stores oxygen in muscle cells.

Question 31

The binding of a myosin head to an actin molecule is termed a:

A)crossbridge.
B)power stroke.
C)triad.
D)synaptic cleft.

Question 32

What is required for excitation-contraction coupling?

A)calcium ions and ATP
B)ATP only
C)calcium ions only
D)neither calcium ions nor ATP

Question 33

What is a necessary reactant for glycolytic,or anaerobic,catabolism to proceed?

A)creatine phosphate
B)oxygen
C)myoglobin
D)glucose

Question 34

What happens when troponin and tropomyosin block the active sites of actin?

A)The muscle contraction reaches peak tension.
B)The muscle contraction increases tension.
C)The muscle relaxes.
D)The muscle produces a weak contraction.

Question 35

Place the following events of excitation in the correct order. 1.ion channels on the sarcolemma open and sodium ions enter the muscle fiber
2)the entry of sodium ions into the muscle fiber depolarizes the sarcolemma locally
3)acetylcholine is released from vesicles in the motor neuron into the synaptic cleft
4)an action potential arrives at the axon terminal of a motor neuron
5)acetylcholine binds to ligand-gated sodium ion channels in the motor end plate

A)2,4,3,5,1
B)4,3,5,1,2
C)4,5,3,2,1
D)3,4,5,1,2

Question 36

What is accomplished by the power stroke?

A)The power stroke cocks the myosin head into its high-energy position.
B)The power stroke allows the myosin heads to bind to actin.
C)The power stroke results in myosin heads pulling actin toward the center of the sarcomere.
D)The power stroke causes the myosin and actin filaments to shorten and contract.

Question 37

The main immediate source of ATP (lasting about 10 seconds)as muscle contractions begin comes from:

A)creatine phosphate.
B)glucose.
C)glycogen.
D)fat.

Question 38

Which of the following promotes the depolarization stage?

A)opening of voltage-gated sodium ion channels and sodium ions enter the cell
B)closure of voltage-gated sodium ion channels
C)opening of voltage-gated potassium ion channels and potassium ions exit the cell
D)hydrolysis of ATP

Question 39

What value best represents resting membrane potential of skeletal muscle cells?

A)+35 mV
B)-90 mV
C)0 mV
D)+15 mV

Question 40

When an action potential arrives in an axon terminal,synaptic vesicles containing acetylcholine are released by:

A)exocytosis.
B)facilitated diffusion.
C)osmosis.
D)endocytosis.

Question 41

What type of contraction requires the greatest amount of tension?

A)isometric contraction
B)isotonic concentric contraction
C)miometric contraction
D)isotonic eccentric contraction

Question 42

Larry's muscles weakened while he played tennis for hours on a hot summer afternoon.This inability to maintain intensity is defined as:

A)hypotonia.
B)hypertonia.
C)atrophy.
D)muscular fatigue.

Question 43

The type of contraction in which length of the muscle fibers do not change is called:

A)isotonic eccentric.
B)tetany.
C)isotonic concentric.
D)isometric.

Question 44

Define excitability.

Question 45

What do skeletal muscle contractions share in common with smooth muscle contractions?

A)Both types of contractions do not require calcium ions for a contraction to occur.
B)Both types of contractions consume very little ATP.
C)Both types of contractions result from thick and thin filaments sliding past one another.
D)Both types of contractions generate little force or a weak force.

Question 46

Clostridium botulinum is a bacterium that produces botulinum toxin that inhibits the release of acetylcholine.Which description best fits how muscle cells will respond to a lack of acetylcholine?

A)Muscle cells will experienced fused or complete tetanus when there is a lack of acetylcholine.
B)Muscle cells will produce greater tension when there is a lack of acetylcholine.
C)Muscle cells will become paralyzed when there is a lack of acetylcholine.
D)Muscle cells will produce sustained contractions without relaxation when there is a lack of acetylcholine.

Question 47

Resting muscles still have some degree of muscle tension produced by involuntary activation of motor units in the brain and spinal cord.This small amount of muscle tension is known as:

A)recruitment.
B)fused (complete)tetanus.
C)muscle tone.
D)isotonic contraction.

Question 48

The fastest muscle contraction would be produced by a:

A)type III fiber.
B)type I fiber.
C)type IIx fiber.
D)type IIa fiber.

Question 49

During the recovery period after exercise,we breathe deeper and faster.This increased rate of respiration is known as:

A)oxidative catabolism.
B)lactic acid buildup.
C)muscular fatigue.
D)excess postexercise oxygen consumption (EPOC).

Question 50

Type I fibers lack:

A)mitochondria.
B)myoglobin.
C)a blood supply.
D)speed.

Question 51

What are the inward extensions of the sarcolemma into the muscle cell called? What function do these extensions serve?

Question 52

Latrotoxin,produced by the poisonous black widow spider,increases the release of acetylcholine.How do muscle cells respond?

A)Muscle cells will become paralyzed when excess acetylcholine exists.
B)Muscle cells will experience fused or complete tetanus when excess acetylcholine exists.
C)Muscle cells will twitch irregularly when excess acetylcholine exists.
D)Muscle cells will experience a longer latent period when excess acetylcholine exists.

Question 53

Which fiber type allows Frances to stand for hours in her job as a nurse?

A)type IIa fiber
B)type I fiber
C)type IIx fiber
D)type III fiber

Question 54

Jorge tried to pick up his sofa but discover that it is much heavier than he expected.What must occur in the muscle to increase tension so he can pick up this heavy piece of furniture?

A)recruitment of additional motor units
B)tetanic spasm
C)isotonic eccentric contractions
D)pliometric contraction

Question 55

Describe the roles of contractile and regulatory proteins in the myofibril.

Question 56

When muscle fibers are stimulated so frequently they do not have an opportunity to relax,they are experiencing:

A)fused or complete tetanus.
B)a twitch.
C)wave summation.
D)unfused or incomplete tetanus.

Question 57

In response to physical inactivity,we expect to see muscles:

A)hypertrophy.
B)increase the diameter of the muscle fiber.
C)atrophy.
D)increase numbers of myofibrils.

Question 58

A single motor neuron together with all the skeletal muscle fibers it innervates is called a:

A)motor unit.
B)synaptic cleft.
C)neuromuscular junction.
D)motor end plate.

Question 59

Smooth muscle and skeletal muscle both possess:

A)motor end plates.
B)myosin and actin filaments.
C)troponin.
D)transverse tubules (T-tubules).

Question 60

Explain the structure and function of the endomysium.

Question 61

The function of the sarcoplasmic reticulum (SR)is to store and release calcium ions.

Question 62

What is the function of the sarcoplasmic reticulum?

Question 63

Describe the role of calcium in the regulation of the troponin-tropomyosin complex.

Question 64

Briefly discuss the role of the myosin heads in the sliding filament mechanism of muscle contraction.

Question 65

Discuss the type of contractions produced by type I muscle fibers.

Question 66

Describe the events of the relaxation period of a muscle twitch.

Question 67

How does hypertrophy change a muscle? Does endurance training or resistance training promote muscle hypertrophy?

Question 68

List and describe the types of contractile and regulatory proteins found in a thin filament.

Question 69

Skeletal muscle fibers possess intercalated discs.

Question 70

Explain why myoglobin is useful to oxidative (aerobic)catabolism.

Question 71

Explain how a sarcomere is affected when thin filaments slide past thick filaments during muscle contraction.

Question 72

Contractility is the ability of a muscle to shorten.

Question 73

Describe the bands that create the light and dark areas of skeletal muscle fibers known as striations.

Question 74

Explain where sodium and potassium ions are located relative to a muscle cell during resting membrane potential.

Question 75

Summarize the steps of the crossbridge cycle.

Question 76

Explain the role sodium ions play in the depolarization stage of the action potential.

Question 77

Explain the role of acetylcholine in the excitation phase of excitation-contraction coupling.

Question 78

Determine how muscles are affected if the muscle receives stimulations so frequently that it has no opportunity to relax between them.

Question 79

Determine the type of muscle contraction needed to lower a heavy bowling ball down by your side so you can roll it down the lane.

Question 80

Describe the synaptic cleft.