NASM Applied Sciences & Nutrition 3

Question 1

Which structure is the functional unit of the muscle responsible for contraction?

Accepted Answer

Sarcomere

Answer

The sarcomere is the smallest contractile unit of skeletal muscle, defined by the area between two Z-lines.

Question 2

During the sliding filament theory, which protein filament physically pulls the actin toward the center of the sarcomere?

Accepted Answer

Myosin

Answer

Myosin cross-bridges attach to actin and pull it inward, shortening the sarcomere.

Question 3

Which type of muscle fiber is best suited for prolonged, low-intensity aerobic endurance activity?

Accepted Answer

Type I (slow-twitch) fibers

Answer

Type I slow-twitch fibers are fatigue-resistant and rely on aerobic metabolism, ideal for endurance.

Question 4

What neurotransmitter is released at the neuromuscular junction to initiate muscle contraction?

Accepted Answer

Acetylcholine

Answer

Acetylcholine is released at the motor end plate to trigger an action potential in the muscle fiber.

Question 5

A motor unit consists of which two components?

Accepted Answer

A motor neuron and all the muscle fibers it innervates

Answer

A motor unit is a single motor neuron together with all of the muscle fibers it innervates.

NASM Practice Test