Question 1

Which of the following statements best describes the role of the sarcoplasmic reticulum (SR) in skeletal muscle contraction?

Accepted Answer

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

Question 2

A patient is experiencing muscle fatigue after prolonged exercise. Which of the following is NOT a direct cause of muscular fatigue according to the study materials?

Accepted Answer

Increased synthesis of myofibrils

Question 3

During a muscle twitch, which phase corresponds to the time when calcium ions are actively pumped back into the sarcoplasmic reticulum?

Accepted Answer

The relaxation period

Question 4

Which of the following best explains why slow-twitch muscle fibers are more resistant to fatigue than fast-twitch fibers?

Accepted Answer

They have a higher number of mitochondria and rely on oxidative metabolism for ATP production.

Question 5

Which neurotransmitter is released at the neuromuscular junction to stimulate skeletal muscle contraction?

Accepted Answer

Acetylcholine (ACh)

Question 6

A muscle fiber is stimulated and an action potential travels down the T-tubules. What is the next immediate event in the process of muscle contraction?

Accepted Answer

Calcium ions are released from the sarcoplasmic reticulum.

Question 7

Which of the following equations correctly represents the breakdown of glucose during glycolysis in muscle cells?

Accepted Answer

$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 \rightarrow 2\ \mathrm{C}_3\mathrm{H}_4\mathrm{O}_3 + 2\ \mathrm{ATP}$

Question 8

Which of the following is a property of muscle cells that allows them to respond to a stimulus by generating an action potential?

Accepted Answer

Excitability

Question 9

A muscle is producing tension but its length remains unchanged. What type of contraction is this?

Accepted Answer

Isometric contraction

Question 10

Which of the following best describes the function of myofibrils in muscle cells?

Accepted Answer

They are cylindrical organelles composed of bundles of specialized proteins that allow for contraction.

Question 11

A muscle fiber is unable to respond to a second stimulus because it is still in the refractory period. Which phase of the muscle twitch does this correspond to?

Accepted Answer

The period after the latent period and before the end of the contraction period

Question 12

Which of the following is TRUE regarding the arrangement of thick and thin filaments in a sarcomere?

Accepted Answer

The A band contains both thick and thin filaments.

Question 13

Which of the following muscle fiber types is most likely to predominate in the postural muscles of the back?

Accepted Answer

Type I (slow-twitch) fibers

Question 14

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

Accepted Answer

Action potential arrives at axon terminal → ACh released into synaptic cleft → ACh binds to receptors on motor end plate → Na$^+$ influx → muscle action potential

Question 15

Which of the following statements about motor units is correct?

Accepted Answer

Muscles requiring fine motor control have small motor units.

Question 16

Which protein blocks the myosin binding sites on actin in a relaxed muscle fiber?

Accepted Answer

Tropomyosin

Question 17

Which of the following is the main immediate source of energy for muscle contraction?

Accepted Answer

ATP stored in the muscle fiber

Question 18

A sprinter relies on fast-twitch muscle fibers during a 100-meter dash. Which metabolic pathway is primarily used for ATP production in these fibers?

Accepted Answer

Glycolytic (anaerobic) catabolism

Question 19

Which of the following best describes the function of myoglobin in muscle cells?

Accepted Answer

It binds and stores oxygen for use during muscle contraction.

Question 20

Which of the following events directly causes the power stroke during muscle contraction?

Accepted Answer

The release of ADP and Pi from the myosin head

Muscle Tissue: Structure, Function, and Physiology

Study Guide - Practice Questions

Study Guide - Flashcards