Question 1

Which of the following statements best describes the structural differences between skeletal, cardiac, and smooth muscle cells?

Accepted Answer

Skeletal muscle cells are multinucleate and striated; cardiac muscle cells are uninucleate, striated, and branched; smooth muscle cells are uninucleate and non-striated.

Question 2

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

Accepted Answer

Increase in oxygen delivery to muscle cells

Question 3

Which connective tissue layer directly surrounds a single skeletal muscle fiber?

Accepted Answer

Endomysium

Question 4

During the sliding filament theory of muscle contraction, which event occurs immediately after calcium ions bind to regulatory proteins on actin?

Accepted Answer

Myosin heads attach to exposed binding sites on actin, forming cross bridges.

Question 5

Which of the following best explains why skeletal muscle is considered voluntary?

Accepted Answer

It is the only muscle tissue subject to conscious control.

Question 6

A muscle cell returns to its resting state after contraction by which of the following mechanisms?

Accepted Answer

Potassium ions diffuse out and the sodium-potassium pump restores ion positions.

Question 7

Which pathway provides the fastest means of regenerating ATP during short, intense muscle activity?

Accepted Answer

Direct phosphorylation of ADP by creatine phosphate

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 TRUE regarding the role of ATP in muscle contraction?

Accepted Answer

ATP provides energy for myosin heads to pivot and detach during contraction.

Question 10

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

Accepted Answer

It breaks down acetylcholine, ending muscle contraction.

Question 11

A marathon runner relies primarily on which pathway for ATP production during the race?

Accepted Answer

Aerobic respiration

Question 12

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

Accepted Answer

Nerve impulse → Calcium influx → ACh release → ACh binds sarcolemma → Na$$^{+}$$ influx → Action potential

Question 13

Which muscle type is found primarily in the walls of hollow visceral organs and is responsible for slow, sustained contractions?

Accepted Answer

Smooth muscle

Question 14

Which of the following best describes the 'all-or-none' law of muscle fiber contraction?

Accepted Answer

A muscle fiber contracts to its fullest extent when stimulated adequately.

Question 15

Which of the following is a function unique to skeletal muscle compared to other muscle types?

Accepted Answer

Maintaining posture and stabilizing joints

Question 16

Which of the following best explains why resistance (isometric) exercise increases muscle size?

Accepted Answer

Individual muscle fibers enlarge (hypertrophy) due to increased tension.

Question 17

Which of the following equations correctly represents the direct phosphorylation of ADP by creatine phosphate?

Accepted Answer

$$\mathrm{CP} + \mathrm{ADP} \rightarrow \mathrm{Creatine} + \mathrm{ATP}$$

Question 18

Which of the following is TRUE regarding the sarcomere during muscle contraction?

Accepted Answer

The H zone disappears as actin and myosin filaments overlap.

Question 19

A patient is unable to produce acetylcholinesterase (AChE) at the neuromuscular junction. What is the most likely effect?

Accepted Answer

Prolonged muscle contraction due to continued presence of acetylcholine.

Study Notes: The Muscular System (Anatomy & Physiology)

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