Question 1

Which of the following statements best describes the difference between skeletal, cardiac, and smooth muscle tissue?

Accepted Answer

Skeletal muscle is voluntary and striated, cardiac muscle is involuntary and striated, and smooth muscle is involuntary and non-striated.

Question 2

A patient is experiencing difficulty with voluntary movements but has no issues with involuntary muscle actions such as heartbeat and digestion. Which muscle type is most likely affected?

Accepted Answer

Skeletal muscle

Question 3

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

Accepted Answer

Endomysium

Question 4

During a muscle contraction, which of the following events occurs according to the sliding filament theory?

Accepted Answer

Calcium ions bind to regulatory proteins on thin filaments, exposing myosin-binding sites and allowing cross-bridge formation.

Question 5

Which of the following best explains why cardiac muscle cells can contract in a coordinated, rhythmic manner?

Accepted Answer

They are connected by intercalated discs containing gap junctions, allowing electrical impulses to pass rapidly between cells.

Question 6

A muscle fiber is stimulated by a motor neuron. Which of the following sequences correctly describes the events at the neuromuscular junction leading to muscle contraction?

Accepted Answer

Release of acetylcholine → opening of sodium channels → depolarization of sarcolemma → action potential generation

Question 7

Which of the following is the correct formula for the direct phosphorylation of ADP by creatine phosphate (CP) in muscle cells?

Accepted Answer

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

Question 8

Which of the following best describes the role of the sarcoplasmic reticulum in skeletal muscle contraction?

Accepted Answer

It stores and releases calcium ions, which are essential for initiating contraction.

Question 9

A marathon runner relies primarily on which pathway for ATP regeneration during prolonged, moderate exercise?

Accepted Answer

Aerobic respiration (oxidative phosphorylation)

Question 10

Which of the following is a characteristic unique to smooth muscle tissue?

Accepted Answer

Cells are spindle-shaped, uninucleate, and lack striations

Question 11

A patient is unable to maintain posture and body position, but their heart and digestive system function normally. Which muscle type is most likely impaired?

Accepted Answer

Skeletal muscle

Question 12

Which of the following best explains why muscle fatigue occurs during strenuous exercise?

Accepted Answer

Ion imbalances (such as Ca$$^{2+}$$ and K$$^{+}$$), oxygen deficit, and lactic acid accumulation

Question 13

Which of the following best describes the 'all-or-none' law as it applies to skeletal muscle fibers?

Accepted Answer

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

Question 14

Which of the following is true regarding isometric muscle contractions?

Accepted Answer

Tension increases but the muscle does not shorten.

Question 15

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 16

Which of the following best explains why the H zone of a sarcomere disappears during muscle contraction?

Accepted Answer

The thin (actin) filaments slide toward the center, overlapping with the thick (myosin) filaments.

Question 17

Which of the following is the correct sequence of events for the generation of an action potential in a muscle fiber?

Accepted Answer

Sodium ions enter the cell, depolarizing the membrane; action potential is generated and spreads along the sarcolemma.

Question 18

Which of the following best describes the effect of aerobic (endurance) exercise on skeletal muscles?

Accepted Answer

It increases muscle size, strength, and resistance to fatigue by making muscles more flexible and efficient.

Question 19

Which of the following is a correct statement about the energy yield of aerobic respiration compared to anaerobic glycolysis in muscle cells?

Accepted Answer

Aerobic respiration produces about 32 ATP per glucose molecule, while anaerobic glycolysis produces about 2 ATP per glucose.

The Muscular System: Structure and Function

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