A heart valve opens and closes due to
A)being pulled by the heart muscle
B)pressure differences on the valve's two sides
C)Na+ and K+ fluxes during ventricular depolarization
D)turbulent flow in the atria and ventricles
E)none of the above

Question

Quizplus · Accepted Answer

The opening and closing of a heart valve is due to pressure differences on the valve's two sides. When the pressure on one side is greater than the pressure on the other side, the valve opens to allow blood flow. When the pressure on the other side becomes greater, the valve closes to prevent backflow. The action of the heart muscles do not directly open and close heart valves, although the movement of the heart's chambers does contribute to the pressure differences that cause the valves to open and close. The action potential involving Na+ and K+ fluxes during ventricular depolarization is involved in generating the cardiac cycle but not the opening and closing of the heart valves. Turbulent flow in the atria and ventricles may cause heart murmurs but it does not cause the opening and closing of heart valves.

A Heart Valve Opens and Closes Due to