Question 1

Which connective tissue layer surrounds an individual muscle fiber in skeletal muscle?

Accepted Answer

Endomysium

Question 2

During muscle contraction, which structure shortens as actin and myosin filaments slide past each other?

Accepted Answer

Sarcomere

Question 3

What is the primary function of the sodium-potassium pump ($$\mathrm{Na^+/K^+}$$ ATPase) in maintaining resting membrane potential?

Accepted Answer

It actively transports $$3$$ sodium ions out and $$2$$ potassium ions in, maintaining a negative charge inside the cell.

Question 4

Which event directly triggers the release of calcium ions from the sarcoplasmic reticulum during excitation-contraction coupling?

Accepted Answer

Depolarization of the T-tubule membrane

Question 5

Which of the following best describes the role of ATP in muscle contraction and relaxation?

Accepted Answer

ATP is required both to detach myosin heads from actin and to pump calcium back into the sarcoplasmic reticulum.

Question 6

A patient is unable to maintain muscle contraction after repeated stimulation, but the muscle still responds to single stimuli. Which phenomenon best explains this observation?

Accepted Answer

Muscle fatigue

Question 7

Which of the following is TRUE regarding the length-tension relationship in skeletal muscle?

Accepted Answer

Maximum tension is produced when the muscle is at an optimal resting length, allowing maximal overlap of actin and myosin.

Question 8

Which of the following best describes the difference between isotonic and isometric muscle contractions?

Accepted Answer

Isotonic contractions involve muscle length change with constant tension; isometric contractions involve tension without change in muscle length.

Question 9

Which of the following is a correct sequence of events at the neuromuscular junction leading to muscle contraction?

Accepted Answer

Acetylcholine binds to receptors, sodium channels open, action potential travels along sarcolemma, calcium released from sarcoplasmic reticulum

Question 10

Which structure is the contractile unit of a muscle fiber?

Accepted Answer

Sarcomere

Question 11

During aerobic respiration, how many molecules of ATP are synthesized from one molecule of glucose?

Accepted Answer

$$36 to$$ $$38$$

Question 12

Which type of muscle fiber would you expect to predominate in the leg muscles of a long-distance runner?

Accepted Answer

Slow oxidative fibers

Question 13

What is the effect of acetylcholine binding to its receptor on the muscle cell membrane?

Accepted Answer

It opens sodium channels, leading to depolarization of the sarcolemma.

Question 14

Which of the following best describes muscle hypertrophy?

Accepted Answer

Increase in the size of existing muscle fibers due to increased protein synthesis

Question 15

Which of the following is NOT a function of skeletal muscle tissue?

Accepted Answer

Blood pump

Question 16

Which molecule binds to troponin to initiate muscle contraction?

Accepted Answer

Calcium

Question 17

Which of the following best explains the staircase effect (treppe) observed in muscle contraction?

Accepted Answer

A gradual increase in contraction strength due to repeated stimulation after complete relaxation

Question 18

Which part of the sarcomere does NOT change length during muscle contraction?

Accepted Answer

A band

Question 19

Which of the following is a correct example of an eccentric muscle contraction?

Accepted Answer

Lowering a dumbbell slowly during a biceps curl

Question 20

Which energy source can supply ATP for the longest duration during sustained muscle activity?

Accepted Answer

Aerobic respiration

Skeletal Muscle Tissue: Structure, Function, and Physiology Study Guide

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