Question 1

Which membrane surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 2

During muscle contraction, which protein directly binds to calcium ions to initiate the exposure of binding sites on actin?

Accepted Answer

Troponin

Question 3

Which structure stores calcium ions in skeletal muscle cells and releases them upon stimulation?

Accepted Answer

Sarcoplasmic reticulum (SR)

Question 4

What is the primary function of acetylcholinesterase (AChE) at the neuromuscular junction?

Accepted Answer

Breaks down acetylcholine to terminate the signal

Question 5

Which equation correctly represents the reaction catalyzed by creatine kinase for rapid ATP regeneration in muscle cells?

Accepted Answer

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

Question 6

A patient is unable to maintain muscle contraction for long periods and experiences rapid fatigue. Which process is most likely impaired?

Accepted Answer

Aerobic respiration in mitochondria

Question 7

Which of the following best describes the difference between isometric and isotonic muscle contractions?

Accepted Answer

Isometric contractions generate tension without changing muscle length, isotonic contractions change muscle length

Question 8

Which of the following is true about oxidative (slow-twitch) muscle fibers compared to glycolytic (fast-twitch) fibers?

Accepted Answer

Oxidative fibers have more mitochondria and myoglobin

Question 9

Which process generates the greatest number of ATP molecules per glucose molecule in muscle cells?

Accepted Answer

Aerobic respiration

Question 10

During the sliding filament model of muscle contraction, which event occurs first?

Accepted Answer

Calcium ions bind to troponin

Question 11

Which of the following is a symptom of myasthenia gravis?

Accepted Answer

Progressive muscle weakness due to loss of acetylcholine receptors

Question 12

Which of the following best explains oxygen debt after intense exercise?

Accepted Answer

The amount of oxygen required to restore ATP and clear lactic acid

Question 13

Which of the following is NOT a result of resistance exercise adaptation in muscle?

Accepted Answer

Decreased muscle fiber diameter

Question 14

Smooth muscle differs from skeletal muscle in that smooth muscle:

Accepted Answer

Contracts more slowly and uses calmodulin instead of troponin

Question 15

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

Accepted Answer

$$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\mathrm{O}_2 \rightarrow 6\mathrm{CO}_2 + 6\mathrm{H}_2\mathrm{O} + 32\ \mathrm{ATP}$$

Question 16

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

Accepted Answer

Binds and stores oxygen for aerobic metabolism

Question 17

A muscle cramp is most likely caused by:

Accepted Answer

Depletion of ATP and accumulation of lactic acid

Question 18

Which of the following is true about the recruitment principle in muscle contraction?

Accepted Answer

Smaller motor units are recruited first, followed by larger ones as needed

Question 19

Which of the following is a characteristic of muscular dystrophy?

Accepted Answer

Progressive degeneration of muscle fibers due to genetic mutation

Question 20

Which of the following best describes the function of the T tubules in skeletal muscle?

Accepted Answer

Transmit action potentials deep into the muscle fiber

Muscle Physiology: Chapter 9 Study Guide – Anatomy & Physiology

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