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

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 contraction cycle, what event directly triggers the exposure of myosin binding sites on actin?

Accepted Answer

Calcium ions bind to troponin, causing tropomyosin to shift.

Question 3

A drug that blocks acetylcholine release at the neuromuscular junction would most likely result in:

Accepted Answer

Paralysis due to inability to initiate muscle contraction.

Question 4

Which of the following statements about the sliding filament theory is correct?

Accepted Answer

Thin filaments slide past thick filaments, causing sarcomere shortening without changing filament length.

Question 5

If acetylcholinesterase (AChE) is absent from the synaptic cleft, what would be the most likely outcome?

Accepted Answer

Continuous stimulation of the muscle fiber, leading to prolonged contraction.

Question 6

Which connective tissue layer surrounds individual skeletal muscle fibers?

Accepted Answer

Endomysium

Question 7

A patient presents with muscle weakness after being immobilized in a cast for six weeks. Which process best explains this phenomenon?

Accepted Answer

Muscle atrophy due to lack of stimulation and decreased muscle fiber size.

Question 8

Which of the following equations correctly represents the breakdown of glucose during aerobic metabolism in skeletal muscle?

Accepted Answer

$	ext{C}_6	ext{H}_{12}	ext{O}_6 + 6	ext{O}_2 ightarrow 6	ext{CO}_2 + 6	ext{H}_2	ext{O} + 	ext{ATP}$

Question 9

Which phase of a muscle twitch is characterized by calcium binding to troponin and cross-bridge cycling?

Accepted Answer

Contraction phase

Question 10

During peak muscle activity, most ATP is produced by which process?

Accepted Answer

Anaerobic metabolism of glucose to lactic acid

Question 11

Which of the following best explains the phenomenon of rigor mortis?

Accepted Answer

Lack of ATP prevents cross-bridge detachment, resulting in sustained muscle contraction.

Question 12

Which of the following is true regarding motor units and precision of movement?

Accepted Answer

Smaller motor units allow for more precise movements.

Question 13

Which of the following is a correct description of an isometric contraction?

Accepted Answer

Muscle length remains the same while tension increases.

Question 14

Which of the following best describes the Cori cycle?

Accepted Answer

Lactate produced in muscle is transported to the liver, converted to pyruvate, and then to glucose.

Question 15

Which of the following events occurs during the relaxation phase of a muscle twitch?

Accepted Answer

Calcium levels fall, cross-bridges detach, and tension returns to resting level.

Question 16

Which of the following is a real-life application of muscle tone?

Accepted Answer

Maintaining posture while sitting upright for extended periods.

Question 17

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

Accepted Answer

Propelling blood through the heart

Question 18

Which of the following best describes the relationship between muscle fibers, myofibrils, and myofilaments?

Accepted Answer

Muscle fibers contain myofibrils, which are composed of myofilaments.

Question 19

Which of the following would most likely occur if a muscle lacked ATP during contraction?

Accepted Answer

Cross-bridges would remain attached, resulting in sustained contraction.

Question 20

Which of the following is a plausible explanation for why a dead body becomes rigid several hours after death?

Accepted Answer

Calcium leaks into the sarcoplasm and, without ATP, cross-bridges cannot detach, causing rigor mortis.

The Muscular System: Structure, Function, and Physiology

Study Guide - Practice Questions