Question

The "all-or-none" concept of skeletal muscle contraction means that

• A. All muscles contract completely and not partially
• B. Muscle fascicles contract completely
• C. Muscle fibers contract completely
• D. All of the actin and myosin molecules contract

Answer 1

The correct option is C

Muscle fibers contract completely

The all-or-none law is the principle that the strength by which a nerve or muscle fiber responds to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential, the nerve or muscle fiber will give a complete response; otherwise, there is no response