Question

The opening and closing of the heart valves is caused by Multiple Choice action potentials within the cusps of the valves. pressure changes of alternating contraction and relaxation during the cardiac cycle. contraction and relaxation of papillary muscles that pull on heart strings. contraction of the smooth muscle in the walls of the great vessels leaving the heart.

Answer 1

pressure changes of alternating contraction and relaxation during the cardiac cycle.

Step-by-step explanation:

In Human anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.

Generally, the cardiac cycle occurs in two (2) stages;

I. Diastole : in this stage, the ventricles is relaxed and would be filled with blood.

II. Systole: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.

Hence, the opening and closing of the heart valves is caused by pressure changes of alternating contraction and relaxation during the cardiac cycle.