Question

Which of the following correctly lists the stages of a basic single muscle twitch?

a. Contraction, relaxation, stimulation, refractory period
b. Latent period, contraction, relaxation, refractory period
c. Relaxation, latent period, contraction, refractory period
d. Refractory period, relaxation, latent period, contraction

Answer 1

The stages of a basic single muscle twitch are latent period, contraction, relaxation, and refractory period. The correct option is (b).

Step-by-step explanation:

The correct answer is b. Latent period, contraction, relaxation, refractory period.

The stages of a basic single muscle twitch are as follows:

1. Latent Period: During this phase, the action potential is being propagated along the sarcolemma.
2. Contraction: In this phase, calcium ions bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten.
3. Relaxation: Tension decreases as calcium ions are pumped out of the sarcoplasm and cross-bridge cycling stops.
4. Refractory Period: This is the recovery phase of the muscle fiber where it is unable to respond to another stimulus.