In cardiac muscle,the fast depolarization phase of the action potential is the result of ________ membrane permeability to ________ ions.
A)increased; sodium
B)increased; potassium
C)decreased; calcium
D)decreased; sodium
E)increased; chloride

Question

Quizplus · Accepted Answer

The fast depolarization phase of the action potential in cardiac muscle is due to an increased membrane permeability to sodium ions. This occurs when voltage-gated sodium channels open and sodium ions flood into the cell, rapidly depolarizing the membrane towards its threshold potential.

In Cardiac Muscle,the Fast Depolarization Phase of the Action Potential