Question 1

Which of the following best describes the role of the sarcoplasmic reticulum in skeletal muscle contraction?

Accepted Answer

It stores and releases calcium ions necessary for muscle contraction.

Question 2

A patient is unable to flex their forearm at the elbow. Which muscle is most likely impaired?

Accepted Answer

Biceps brachii

Question 3

During the contraction phase of a muscle twitch, which of the following occurs?

Accepted Answer

Cross-bridge interactions between actin and myosin increase, generating tension.

Question 4

Which of the following is TRUE regarding the sliding filament theory?

Accepted Answer

Thin filaments slide toward the center of the sarcomere, while thick filaments remain stationary.

Question 5

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

Accepted Answer

They rely primarily on glycolysis, which produces less ATP and more lactic acid.

Question 6

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

Accepted Answer

Synergist

Question 7

Which of the following is a function of the pelvic floor muscles?

Accepted Answer

Support the organs of the pelvic cavity

Question 8

Which process provides the majority of ATP for a muscle cell during moderate, sustained activity?

Accepted Answer

Aerobic metabolism in mitochondria

Question 9

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

Accepted Answer

Isotonic contractions change muscle length, while isometric contractions do not.

Question 10

A person is pushing against a wall with all their strength, but the wall does not move. Which type of muscle contraction is occurring?

Accepted Answer

Isometric contraction

Question 11

Which of the following is the correct sequence of events for muscle contraction initiation?

Accepted Answer

ACh release → Action potential → Ca$$^{2+}$$ release → Cross-bridge formation

Question 12

Which of the following is a characteristic unique to cardiac muscle tissue?

Accepted Answer

Presence of intercalated discs

Question 13

Which muscle is the prime mover (agonist) for abduction of the arm at the shoulder?

Accepted Answer

Deltoid

Question 14

Which of the following best explains why muscle atrophy occurs after a limb is immobilized in a cast?

Accepted Answer

Lack of regular stimulation by motor neurons causes muscle fibers to become smaller and weaker.

Question 15

Which of the following is a correct description of the H band in a sarcomere?

Accepted Answer

It contains only thick filaments when the muscle fiber is relaxed.

Question 16

Which of the following is a function of the diaphragm muscle?

Accepted Answer

Separates the thoracic and abdominopelvic cavities

Question 17

Which of the following best describes the role of creatine phosphate (CP) in muscle contraction?

Accepted Answer

It donates a phosphate group to ADP to rapidly regenerate ATP during the initial seconds of contraction.

Question 18

Which of the following is a real-life example of an incomplete tetanus in skeletal muscle?

Accepted Answer

Shivering to generate heat when cold

Question 19

Which muscle group is primarily responsible for extending the knee joint?

Accepted Answer

Quadriceps femoris

Question 20

Which of the following is a distinguishing feature of smooth muscle tissue compared to skeletal muscle tissue?

Accepted Answer

Smooth muscle lacks striations and has spindle-shaped cells.

The Muscular System: Structure, Function, and Organization

Study Guide - Practice Questions