Question

part b (2 of 7)
what structure is the functional unit of contraction in a skeletal muscle fiber?
the junctional folds of the sarcolemma
the triad
the sarcomere
the cross bridge

Explanation:

The sarcomere is the basic functional unit of contraction in a skeletal - muscle fiber. It is the repeating unit between two Z - lines and contains the contractile proteins actin and myosin. The junctional folds of the sarcolemma are involved in the neuromuscular junction, the triad is a structure involved in the coupling of excitation and contraction, and the cross - bridge is part of the mechanism of contraction but not the functional unit.

Answer:

The sarcomere