An action potential in the motor end plate rapidly spreads to the interior regions of a muscle cell by means of the:
A) Z lines.
B) sarcoplasmic reticulum.
C) H zone.
D) transverse tubules.
E) pores in the plasma membrane.

Question

Quizplus · Accepted Answer

The transverse tubules (T-tubules) are invaginations of the sarcolemma that penetrate deep into the muscle fiber, allowing the action potential to quickly spread throughout the entire cell. The Z lines, sarcoplasmic reticulum, H zone, and pores in the plasma membrane do not play a direct role in conducting the action potential throughout the muscle cell.

An Action Potential in the Motor End Plate Rapidly Spreads