The Functional Unit of Muscle Contraction Is

Question

The functional unit of muscle contraction is
A)the muscle.
B)the muscle fiber.
C)the myosin cross-bridge.
D)the sarcomere.

Accepted Answer

The sarcomere is the basic functional unit of skeletal muscle contraction, consisting of overlapping actin and myosin filaments. It is within the sarcomere that the sliding filament theory occurs, where myosin cross-bridges attach to actin and pull the filaments past each other, resulting in muscle contraction. Therefore, option D is the correct answer. A, B, and C are incorrect as they do not fully represent the basic unit of muscle contraction.