MEDICAL PHYSIOLOGY

Detailed explanation-1: -The time between the activation of a motor neuron until the muscle contraction occurs is called the lag phase (sometimes called the latent phase). During the lag phase a signal called an action potential moves to the end of the motor neuron (axon terminal).

Detailed explanation-2: -The latent period, or lag phase, the contraction phase, and the relaxation phase. The latent period is a short delay (1-2 msec) from the time when the action potential reaches the muscle until tension can be observed in the muscle.

Detailed explanation-3: -The time between the stimulus and the initiation of contraction is termed the latent period, which is followed by the contraction period. At peak contraction the muscle relaxes and returns to its resting position. Taken all together these three periods are termed a twitch.

Detailed explanation-4: -During the latent period, the action potential is being propagated along the sarcolemma. During the contraction phase, Ca++ ions in the sarcoplasm bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten.