Question 1

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

Accepted Answer

Skeletal muscle is striated and voluntary, while smooth muscle is nonstriated and involuntary.

Question 2

Which specialized structure in skeletal muscle fibers stores calcium ions and releases them to trigger contraction?

Accepted Answer

Sarcoplasmic reticulum

Question 3

During the sliding filament model of contraction, which event directly causes the muscle fiber to shorten?

Accepted Answer

Actin and myosin filaments slide past each other, causing sarcomeres to shorten.

Question 4

Which connective tissue layer surrounds individual muscle fibers within a fascicle?

Accepted Answer

Endomysium

Question 5

A patient is unable to maintain muscle contraction during prolonged exercise and experiences rapid fatigue. Which metabolic pathway is most likely being used?

Accepted Answer

Anaerobic glycolysis

Question 6

Which of the following best explains why muscle tension increases during temporal summation?

Accepted Answer

Multiple stimuli arrive before the muscle fiber has completely relaxed, causing greater tension.

Question 7

Which protein forms the thick filaments in a myofibril and is responsible for cross-bridge formation during contraction?

Accepted Answer

Myosin

Question 8

What is the role of acetylcholine (ACh) at the neuromuscular junction?

Accepted Answer

It acts as a neurotransmitter that initiates muscle fiber contraction.

Question 9

Which phase of a muscle twitch is defined as the time between stimulus and the beginning of measurable contraction?

Accepted Answer

Latent period

Question 10

A weightlifter is lowering a barbell slowly. Which type of muscle contraction is primarily occurring?

Accepted Answer

Eccentric contraction

Question 11

Which equation correctly represents the regeneration of ATP via the phosphagen system?

Accepted Answer

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

Question 12

Which of the following factors does NOT directly influence the speed of muscle contraction?

Accepted Answer

Amount of myoglobin present

Question 13

Which structure is the plasma membrane of a muscle fiber?

Accepted Answer

Sarcolemma

Question 14

A marathon runner relies primarily on which pathway for ATP production during the race?

Accepted Answer

Aerobic respiration

Question 15

Which of the following best describes the 'motor unit' in skeletal muscle?

Accepted Answer

A single motor neuron and all the muscle fibers it innervates

Question 16

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

Accepted Answer

Tropomyosin

Question 17

If a muscle fiber receives rapid stimuli with no relaxation between twitches, what is the result?

Accepted Answer

Fused (complete) tetanus

Question 18

Which of the following is a function of muscle tissue that helps maintain homeostasis?

Accepted Answer

Producing heat

Question 19

Which equation represents the breakdown of glucose during anaerobic glycolysis?

Accepted Answer

$$\mathrm{Glucose} \rightarrow 2\ \mathrm{ATP} + 2\ \mathrm{Lactate}$$

Question 20

Which of the following is TRUE regarding the recruitment of motor units during muscle contraction?

Accepted Answer

Smaller motor units are recruited first, followed by larger ones as more force is needed.

Muscle Tissue: Structure, Function, and Physiology

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