Question 1

Which of the following best explains why ATP is required during the relaxation phase of skeletal muscle contraction?

Accepted Answer

ATP is required to pump $$Ca^{2+}$$ back into the sarcoplasmic reticulum, allowing muscle relaxation.

Question 2

A patient is unable to detach myosin heads from actin after a muscle contraction. Which cellular process is most likely impaired?

Accepted Answer

Binding of ATP to myosin

Question 3

During which type of muscle contraction does the muscle generate the highest tension while lengthening?

Accepted Answer

Isotonic eccentric contraction

Question 4

Which of the following is a unique structural feature of cardiac muscle that distinguishes it from skeletal muscle?

Accepted Answer

Presence of intercalated discs

Question 5

A marathon runner relies primarily on which muscle fiber type and energy system during a race?

Accepted Answer

Type I fibers and oxidative (aerobic) metabolism

Question 6

Which of the following best describes the role of $$Ca^{2+} in $$smooth muscle contraction?

Accepted Answer

$$Ca^{2+}$$ binds to calmodulin, activating myosin light-chain kinase.

Question 7

Which of the following is NOT a cause of muscle fatigue during intense exercise?

Accepted Answer

Increased oxygen availability

Question 8

A weightlifter holds a heavy barbell stationary above their head without moving it. Which type of muscle contraction is primarily occurring?

Accepted Answer

Isometric contraction

Question 9

Which sequence correctly describes the events at the neuromuscular junction leading to muscle fiber depolarization?

Accepted Answer

ACh is released → binds to motor end plate receptors → $$Na^{+}$$ influx → depolarization

Question 10

Which of the following best explains why smooth muscle does NOT display striations under a microscope?

Accepted Answer

Smooth muscle lacks sarcomeres, so no striations are present.

Question 11

Which of the following best describes the latent period of a muscle twitch?

Accepted Answer

The period when the action potential is spreading but no contraction has occurred yet

Question 12

Which of the following is TRUE regarding the cross-bridge cycle in skeletal muscle contraction?

Accepted Answer

ATP hydrolysis cocks the myosin head, preparing it for binding.

Question 13

Which of the following best explains why Type IIx muscle fibers fatigue more quickly than Type I fibers?

Accepted Answer

Type IIx fibers have fewer mitochondria and less myoglobin, leading to rapid fatigue.

Question 14

Which of the following is the correct order of events in excitation–contraction coupling in skeletal muscle?

Accepted Answer

ACh release → sarcolemma depolarization → $$Ca^{2+}$$ release from SR → $$Ca^{2+}$$ binds troponin → tropomyosin shifts

Question 15

Which of the following best describes the process of wave summation in muscle contraction?

Accepted Answer

Increasing force of contraction due to repeated stimulation before complete relaxation

Question 16

Which of the following is a function of ATP in skeletal muscle contraction?

Accepted Answer

Detachment of myosin from actin after the power stroke

Question 17

Which of the following best describes the role of recruitment in muscle contraction?

Accepted Answer

Activating more motor units to increase overall muscle force

Question 18

Which energy system provides the most efficient long-term ATP production during sustained exercise?

Accepted Answer

Oxidative (aerobic) metabolism

Question 19

Which of the following is a characteristic of single-unit smooth muscle?

Accepted Answer

It contracts as a coordinated unit due to gap junctions.

Question 20

During the recovery period after intense exercise, which of the following processes occurs?

Accepted Answer

ATP stores are rebuilt and metabolic wastes are removed.

Muscle Tissue and Physiology: Study Guide (Chapters 9–10)

Study Guide - Practice Questions