Question 1

Which of the following statements best describes the role of calcium ions ($$\mathrm{Ca$$^{2+}$$}) in $$skeletal muscle contraction?

Accepted Answer

Calcium ions bind regulatory proteins on actin filaments, exposing myosin-binding sites.

Question 2

A patient is experiencing muscle fatigue after strenuous exercise. Which of the following is LEAST likely to contribute to muscle fatigue?

Accepted Answer

Increase in oxygen supply to muscle cells

Question 3

During muscle contraction, which event occurs immediately after acetylcholine (ACh) binds to receptors on the sarcolemma?

Accepted Answer

The sarcolemma becomes more permeable to sodium ions ($$\mathrm{Na^+}).$$

Question 4

Which of the following best explains why skeletal muscle fibers are multinucleate?

Accepted Answer

They are formed by the fusion of multiple embryonic cells, resulting in large, elongated fibers.

Question 5

A muscle contraction in which the muscle tension increases but the muscle does NOT shorten is called:

Accepted Answer

Isometric contraction

Question 6

Which of the following is TRUE regarding the arrangement of fascicles in muscles?

Accepted Answer

Circular muscles have fascicles arranged in concentric rings.

Question 7

Which pathway provides the fastest method for regenerating ATP during short, intense muscle activity?

Accepted Answer

Direct phosphorylation of ADP by creatine phosphate ($$\mathrm{CP})$$

Question 8

If a muscle is stimulated so rapidly that no evidence of relaxation is seen and contractions are smooth and sustained, this state is called:

Accepted Answer

Fused (complete) tetanus

Question 9

Which of the following is a function unique to skeletal muscle compared to cardiac and smooth muscle?

Accepted Answer

Maintaining posture

Question 10

A muscle named 'triceps brachii' is named based on which criteria?

Accepted Answer

Number of origins

Question 11

Which of the following best describes the sliding filament model of muscle contraction?

Accepted Answer

Myosin heads attach to actin, pivot, and detach repeatedly, pulling actin toward the center of the sarcomere.

Question 12

Which of the following movements is an example of abduction?

Accepted Answer

Moving the arm away from the midline of the body

Question 13

During muscle contraction, which band of the sarcomere disappears as actin and myosin filaments overlap?

Accepted Answer

H zone

Question 14

Which of the following is NOT a property of skeletal muscle cells?

Accepted Answer

Ability to push during contraction

Question 15

Which of the following best describes the role of acetylcholinesterase (AChE) at the neuromuscular junction?

Accepted Answer

AChE breaks down acetylcholine, ending muscle contraction.

Question 16

Which of the following is TRUE regarding muscle tone?

Accepted Answer

Muscle tone is a state of continuous partial contraction, keeping muscles firm and ready.

Question 17

Which of the following is a real-life example of an isotonic contraction?

Accepted Answer

Lifting a dumbbell during a bicep curl

Question 18

Which of the following statements about muscle attachments is CORRECT?

Accepted Answer

The insertion moves toward the origin during contraction.

Question 19

Which of the following is a function of the sarcoplasmic reticulum in skeletal muscle cells?

Accepted Answer

Stores and releases calcium ions ($$\mathrm{Ca$$^{2+}$$}) $$for muscle contraction

Question 20

A muscle that aids a prime mover in a movement or reduces undesirable movements is called a:

Accepted Answer

Synergist

The Muscular System: Structure, Function, and Physiology

Study Guide - Practice Questions