Depolarization of a cardiac muscle cell occurs as the result of a:
A) decrease in the permeability of the cell membrane to potassium.
B) rapid movement of sodium into the cell.
C) rapid movement of calcium into the cell.
D) slow movement of sodium out of the cell.
E) slow movement of calcium out of the cell.

Question

Quizplus · Accepted Answer

Depolarization of a cardiac muscle cell is caused by the rapid movement of sodium into the cell, which leads to a positive charge inside the cell and a negative charge outside. This triggers a series of events that leads to the contraction of the muscle cell.

Depolarization of a Cardiac Muscle Cell Occurs as the Result