Applied Sciences & Nutrition Flashcards

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

Answer: Sarcomere

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

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

Answer: Myosin

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

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

Answer: Type I (slow-twitch) fibers

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

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

Answer: Acetylcholine

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

A motor unit consists of which two components?

Answer: A motor neuron and all the muscle fibers it innervates

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

Which mineral is essential for muscle contraction by binding to troponin to expose actin binding sites?

Answer: Calcium

Calcium binds troponin, shifting tropomyosin to expose actin's binding sites for cross-bridge formation.

What is the term for a muscle action in which the muscle lengthens under tension, such as lowering a dumbbell during a biceps curl?

Answer: Eccentric action

An eccentric action occurs when the muscle produces force while lengthening, controlling the load.