The arrival of an action potential causes the release of ____ by the ____.
A)calcium; myofibrils
B)calcium; sarcoplasmic reticulum
C)sodium; myofibrils
D)sodium; sarcoplasmic reticulum
E)actin; myosin heads

Question

Quizplus · Accepted Answer

When an action potential arrives in the muscle cell, it travels down the T-tubules which are invaginations of the sarcolemma (cell membrane) that allow the action potential to reach the sarcoplasmic reticulum (SR). The SR then releases stored calcium ions into the cytoplasm of the muscle cell. This calcium release triggers the contraction of the muscle fibers. Therefore, the correct answer is B - calcium is released by the sarcoplasmic reticulum in response to an action potential.

The Arrival of an Action Potential Causes the Release of ____