Question

The shortest phase of a muscle twitch, usually lasting less than 5 milliseconds, is called the:

O contraction phase.
O relaxation phase.
O latent period.

Answer 1

The shortest phase of a muscle twitch, usually lasting less than 5 milliseconds, is called the latent period. During this phase, the action potential is being propagated along the sarcolemma. After the latent period, the muscle enters the contraction phase, where calcium ions bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten. Finally, the relaxation phase occurs, during which tension decreases as calcium ions are pumped out of the sarcoplasm and cross-bridge cycling stops. latent period.

Step-by-step explanation:

The shortest phase of a muscle twitch, usually lasting less than 5 milliseconds, is called the latent period. During this phase, the action potential is being propagated along the sarcolemma. After the latent period, the muscle enters the contraction phase, where calcium ions bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten. Finally, the relaxation phase occurs, during which tension decreases as calcium ions are pumped out of the sarcoplasm and cross-bridge cycling stops.