During the S-T segment, what is occurring within cardiac muscle cells?
A) Sodium is rapidly diffusing out of atrial muscle cells.
B) Sodium channels are beginning to open in ventricular cells and calcium is entering through slow channels in atrial cells.
C) Calcium is entering and potassium is leaving ventricular cells.
D) Potassium is entering atrial cells and sodium is leaving ventricular cells.

Question

Quizplus · Accepted Answer

During the S-T segment, ventricular muscle cells are in the plateau phase of the action potential, where calcium ions enter the cells through L-type calcium channels and potassium ions leave the cells, maintaining depolarization.

During the S-T Segment, What Is Occurring Within Cardiac Muscle