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 ($$\mathrm{Ca$$^{2+}$$}) $$necessary for muscle contraction.

Question 2

During a muscle contraction, which of the following changes occur in the sarcomere?

Accepted Answer

The I band and H zone decrease in width, while the A band remains unchanged.

Question 3

A patient is unable to relax their muscles after contraction. Which structure is most likely malfunctioning?

Accepted Answer

Sarcoplasmic reticulum, because it fails to reabsorb $$\mathrm{Ca$$^{2+}$$}$$ for relaxation.

Question 4

Which connective tissue layer surrounds a single muscle fiber?

Accepted Answer

Endomysium

Question 5

Which of the following muscle fiber types would be most abundant in the legs of a marathon runner?

Accepted Answer

Slow oxidative fibers (red, fatigue resistant)

Question 6

A muscle contraction is initiated when calcium ions bind to which protein?

Accepted Answer

Troponin

Question 7

Which of the following best describes an isometric contraction?

Accepted Answer

Muscle tension increases, but muscle length does not change.

Question 8

Which arrangement of muscle fibers is found in the deltoid muscle?

Accepted Answer

Multipennate

Question 9

If the biceps brachii contracts, which bone moves toward which bone?

Accepted Answer

The radius moves toward the scapula.

Question 10

Which of the following is NOT a function of skeletal muscle?

Accepted Answer

Production of hormones

Question 11

Which of the following best describes the role of a fixator muscle?

Accepted Answer

It stabilizes the origin of the agonist during movement.

Question 12

Which of the following is the correct sequence of events in skeletal muscle contraction?

Accepted Answer

Nerve impulse → ACh release → Action potential → $$\mathrm{Ca$$^{2+}$$}$$ release → $$\mathrm{Ca$$^{2+}$$}$$ binds troponin → Tropomyosin moves → Myosin binds actin → Power stroke → ATP detaches myosin → Muscle relaxes

Question 13

Which muscle fiber type is most likely to be recruited during a short, intense sprint?

Accepted Answer

Fast glycolytic fibers

Question 14

Which of the following is a real-life example of an isotonic concentric contraction?

Accepted Answer

Lifting a dumbbell during a biceps curl

Question 15

Which of the following is the correct formula for the breakdown of creatine phosphate to regenerate ATP during muscle contraction?

Accepted Answer

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

Question 16

Which of the following best describes the triad in skeletal muscle fibers?

Accepted Answer

One T-tubule plus two terminal cisternae of the sarcoplasmic reticulum

Question 17

Which of the following is a plausible cause of muscle fatigue during intense exercise?

Accepted Answer

Accumulation of lactic acid and depletion of ATP

Question 18

Which muscle arrangement is best suited for generating the greatest force?

Accepted Answer

Multipennate

Question 19

Which of the following muscles is classified as an axial muscle?

Accepted Answer

Rectus abdominis

Question 20

Which of the following best describes the role of the antagonist during elbow flexion?

Accepted Answer

Triceps brachii opposes the action of the biceps brachii.

Skeletal Muscle Structure and Function: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards