Depolarization of a cardiac muscle cell occurs as the result of
A)a decrease in the permeability of the cell membrane to sodium.
B)the opening of voltage-gated sodium channels and voltage-gated calcium channels.
C)the closure of voltage-gated calcium channels.
D)the opening of voltage-gated potassium channels.
E)the closure of the voltage-gated sodium channels.

Question

Quizplus · Accepted Answer

Depolarization of a cardiac muscle cell occurs when voltage-gated sodium channels and voltage-gated calcium channels open, allowing an influx of positive ions (sodium and calcium) into the cell, which makes the membrane potential more positive. This leads to the contraction of the cardiac muscle.

Depolarization of a Cardiac Muscle Cell Occurs as the Result