$$ATP \rightarrow ADP + Pi + \text{energy}$$

Question 1

Which of the following best describes the role of calcium ions ($$Ca^{2+}) in $$muscle contraction?

Accepted Answer

They bind to troponin, causing tropomyosin to move and expose binding sites on actin.

Question 2

Where is myosin located within a muscle fiber?

Accepted Answer

In the thick filaments of the sarcomere

Question 3

Which structure surrounds individual muscle fibers and provides insulation?

Accepted Answer

Endomysium

Question 4

During the sliding filament theory, what is the correct sequence of events for muscle contraction?

Accepted Answer

Calcium binds to troponin, tropomyosin moves, myosin binds to actin, power stroke occurs.

Question 5

Which equation correctly represents the breakdown of ATP during muscle contraction?

Accepted Answer

$$ATP ightarrow ADP + Pi + 	ext{energy}$$

Question 6

Which of the following is a difference between skeletal, cardiac, and smooth muscle tissue?

Accepted Answer

Skeletal muscle fibers are multinucleated, while cardiac and smooth muscle fibers are not.

Question 7

A patient is unable to move their arm after a nerve injury. Which step in the muscle contraction process is most likely disrupted?

Accepted Answer

Transmission of the action potential to the muscle fiber

Question 8

Which of the following best describes the function of acetylcholine at the neuromuscular junction?

Accepted Answer

It depolarizes the muscle fiber membrane, leading to an action potential.

Question 9

Which muscle protein acts as a regulatory protein by blocking myosin binding sites on actin in a relaxed muscle?

Accepted Answer

Tropomyosin

Question 10

Which of the following is the correct order of events for the excitation-contraction coupling in skeletal muscle?

Accepted Answer

Action potential travels down T-tubule, calcium released, myosin binds to actin, muscle contracts.

Question 11

Which of the following is a function of the sarcoplasmic reticulum in muscle fibers?

Accepted Answer

It stores and releases calcium ions ($$Ca^{2+}) $$during muscle contraction.

Question 12

A muscle cramp is most likely caused by which of the following?

Accepted Answer

Continuous stimulation without relaxation due to lack of ATP

Question 13

Which of the following best describes the role of the prime mover (agonist) in a muscle action?

Accepted Answer

It is the main muscle responsible for producing a specific movement.

Question 14

Which of the following is true regarding muscle atrophy?

Accepted Answer

It is the wasting away or decrease in size of muscle tissue due to disuse.

Question 15

Which equation represents the process of aerobic cellular respiration in muscle cells?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{energy}$$

Question 16

Which of the following best explains why muscle fibers are multinucleated?

Accepted Answer

They fuse from multiple myoblasts during development.

Question 17

A patient presents with muscle weakness and fatigue. Blood tests show low acetylcholine levels. Which process is most directly affected?

Accepted Answer

Transmission of the action potential across the neuromuscular junction

Question 18

Which of the following is the correct definition of a motor unit?

Accepted Answer

A group of muscle fibers innervated by a single motor neuron

Question 19

Which of the following best describes the role of ATP in muscle contraction and relaxation?

Accepted Answer

ATP is required both for the power stroke and for detaching myosin from actin during relaxation.

Question 20

Which of the following muscles is located in the lower leg and is responsible for plantar flexion of the foot?

Accepted Answer

Gastrocnemius

Study Guide: The Muscular System (Chapter 6)

Study Guide - Practice Questions