Question 1

Which of the following best describes the role of the sodium-potassium pump in muscle contraction?

Accepted Answer

It maintains the resting membrane potential by actively transporting $$3 \mathrm{Na}^+$$ out and $$2 \mathrm{K}^+$$ into the cell.

Question 2

A sprinter and a marathon runner have different muscle fiber compositions. Which statement best explains the difference?

Accepted Answer

Sprinters have more fast-twitch fibers, which are larger in diameter and fatigue quickly.

Question 3

During a sustained muscle contraction, which event occurs at the neuromuscular junction (NMJ)?

Accepted Answer

Acetylcholine is released from the motor neuron and binds to receptors on the muscle fiber membrane.

Question 4

Which muscle is primarily responsible for flexing the forearm at the elbow?

Accepted Answer

Biceps brachii

Question 5

A patient presents with muscle weakness and fatigue. Laboratory tests reveal antibodies against acetylcholine receptors. What is the most likely diagnosis?

Accepted Answer

Myasthenia gravis

Question 6

Which equation best represents the relationship between muscle force ($$F) $$and cross-sectional area ($$A$$)?

Accepted Answer

$$F = kA$$

Question 7

What is the primary function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

To store and release calcium ions during contraction

Question 8

Which muscle is an antagonist to the biceps brachii during elbow flexion?

Accepted Answer

Triceps brachii

Question 9

A baseball pitcher throws a ball. Which muscle is most responsible for the abduction of the arm at the shoulder?

Accepted Answer

Deltoid

Question 10

Which process explains the increase in muscle size after resistance training?

Accepted Answer

Hypertrophy

Question 11

Which of the following best describes tetanus in muscle physiology?

Accepted Answer

A sustained contraction resulting from rapid, repeated stimuli

Question 12

Which muscle is primarily involved in facial expressions such as smiling?

Accepted Answer

Zygomaticus major

Question 13

During aerobic exercise, which metabolic pathway is primarily used to generate ATP?

Accepted Answer

Oxidative phosphorylation

Question 14

Which muscle is located on the anterior thigh and is responsible for knee extension?

Accepted Answer

Quadriceps femoris

Question 15

Which statement best describes the sliding filament theory of muscle contraction?

Accepted Answer

Myosin heads bind to actin, pulling the filaments past each other, resulting in sarcomere shortening.

Question 16

Which muscle is most responsible for plantar flexion of the foot?

Accepted Answer

Gastrocnemius

Question 17

Which of the following is a synergist in elbow flexion?

Accepted Answer

Brachialis

Question 18

Which muscle is found in the posterior view of the human body and is responsible for shoulder elevation?

Accepted Answer

Trapezius

Question 19

Which condition is characterized by sustained muscle contraction due to a bacterial toxin interfering with inhibitory neurotransmitters?

Accepted Answer

Tetanus

Question 20

A muscle fiber is stimulated at a frequency that does not allow complete relaxation between stimuli. What is the result?

Accepted Answer

Incomplete tetanus

Muscle Physiology and Anatomy: Study Guide for Anatomy & Physiology

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