Question 1

Which property of muscle tissue allows a muscle to return to its original resting length after being stretched?

Accepted Answer

Elasticity

Question 2

During the sliding filament model of muscle contraction, which statement is correct?

Accepted Answer

Actin myofilaments slide over myosin myofilaments, shortening sarcomeres.

Question 3

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 4

A patient is experiencing muscle fatigue after prolonged exercise. Which is the most likely physiological cause?

Accepted Answer

Depletion of ATP within muscle fibers

Question 5

Which equation correctly represents the reaction for ATP regeneration using creatine phosphate?

Accepted Answer

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

Question 6

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

Accepted Answer

Troponin binds calcium ions, causing tropomyosin to move and expose actin binding sites.

Question 7

If a neuron releases acetylcholine at the neuromuscular junction, what is the immediate effect on the muscle cell membrane?

Accepted Answer

It opens ligand-gated sodium channels, leading to depolarization.

Question 8

Which phase of the action potential is primarily responsible for returning the membrane potential to its resting value?

Accepted Answer

Repolarization

Question 9

A muscle fiber is at rest with a membrane potential of $$-80\ \mathrm{mV}. If $$potassium channels open, what will happen to the membrane potential?

Accepted Answer

It will become more negative (hyperpolarize).

Question 10

Which of the following is TRUE regarding slow-twitch muscle fibers?

Accepted Answer

They are specialized for endurance and use aerobic respiration.

Question 11

Which structure in the muscle cell stores calcium ions required for contraction?

Accepted Answer

Sarcoplasmic reticulum

Question 12

What is the primary function of the Z disk in a sarcomere?

Accepted Answer

It serves as an attachment site for actin filaments.

Question 13

Which of the following best explains why rigor mortis occurs after death?

Accepted Answer

ATP is depleted, preventing myosin heads from releasing actin filaments.

Question 14

Which type of muscle contraction involves no change in muscle length but an increase in tension?

Accepted Answer

Isometric contraction

Question 15

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

Accepted Answer

Contraction of the heart to pump blood

Question 16

Which equation best represents the total ATP yield from aerobic respiration of one glucose molecule?

Accepted Answer

$$\mathrm{Glucose} + 6\ \mathrm{O}_2 \rightarrow 6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + 36\ \mathrm{ATP}$$

Question 17

Which statement about smooth muscle is correct?

Accepted Answer

Smooth muscle contraction is regulated by enzymes such as myosin kinase.

Question 18

Which of the following best describes the 'all-or-none' principle in muscle fibers?

Accepted Answer

A muscle fiber contracts maximally if threshold is reached, or not at all.

Question 19

A marathon runner relies primarily on which energy source for sustained muscle contraction?

Accepted Answer

Aerobic respiration

Muscular System: Histology and Physiology – Study Notes

Study Guide - Practice Questions