Question 1

Which of the following best describes the function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

It stores and releases calcium ions necessary for muscle contraction.

Question 2

During the sliding filament theory of muscle contraction, which of the following changes occur in the sarcomere?

Accepted Answer

The H band and I band get smaller, and the Z lines move closer together.

Question 3

A patient is unable to maintain posture and body position. Which function of skeletal muscle is most likely impaired?

Accepted Answer

Maintain posture and body position

Question 4

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 5

What is the role of troponin in muscle contraction?

Accepted Answer

It binds calcium ions, causing a conformational change that moves tropomyosin and exposes active sites on actin.

Question 6

Which of the following is a property shared by all muscle tissue types?

Accepted Answer

Excitability

Question 7

A muscle that assists the prime mover in performing an action is called a:

Accepted Answer

Synergist

Question 8

Which type of skeletal muscle fiber is most resistant to fatigue and why?

Accepted Answer

Slow fibers, because they have abundant mitochondria and use aerobic metabolism.

Question 9

In a third-class lever system, such as the biceps brachii flexing the forearm, which of the following is true?

Accepted Answer

Speed and distance are increased, but the force produced must be great.

Question 10

Which of the following best explains muscle hypertrophy as a result of exercise?

Accepted Answer

An increase in the number of myofibrils, mitochondria, and glycogen reserves within muscle fibers.

Question 11

Which of the following events occurs first during the initiation of skeletal muscle contraction?

Accepted Answer

Release of acetylcholine (ACh) from the motor neuron at the neuromuscular junction.

Question 12

A muscle fiber is observed to have a large diameter, pale color, and few mitochondria. Which type of fiber is this most likely to be?

Accepted Answer

Fast (white) fiber

Question 13

Which of the following best describes the function of muscle tone?

Accepted Answer

It stabilizes the position of bones and joints by maintaining a resting tension in skeletal muscle.

Question 14

If the sarcoplasmic reticulum fails to recapture $$\mathrm{Ca$$^{2+}$$}$$ ions after a contraction, what is the most likely result?

Accepted Answer

The muscle will remain contracted and unable to relax.

Question 15

Which of the following is the correct order of organization from largest to smallest in skeletal muscle structure?

Accepted Answer

Muscle, fascicle, fiber, myofibril, sarcomere

Question 16

A muscle is named 'biceps brachii.' What does the term 'biceps' indicate about the muscle?

Accepted Answer

It has two origins.

Question 17

Which of the following best explains why fast fibers fatigue more quickly than slow fibers?

Accepted Answer

Fast fibers rely primarily on anaerobic metabolism and have fewer mitochondria.

Question 18

Which of the following statements about the A band in a sarcomere is correct?

Accepted Answer

The width of the A band remains constant during contraction.

Question 19

A muscle that opposes the action of the agonist is called a(n):

Accepted Answer

Antagonist

Question 20

Which of the following best describes the effect of aging on skeletal muscle?

Accepted Answer

Skeletal muscle fibers become smaller in diameter and less elastic, and recovery from injury decreases.

Skeletal Muscle Tissue and Organization: Study Notes for Anatomy & Physiology

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