What does the cardiac cycle reveal about the opening and closing of the heart valves?

Question

Quizplus · Accepted Answer

The cardiac cycle involves the AV (atrioventricular) valves closing first to prevent backflow of blood into the atria when the ventricles contract. Then, the semilunar valves open to allow blood to be ejected from the heart into the arteries. After the ventricles relax, the semilunar valves close to prevent backflow from the arteries into the ventricles, followed by the opening of the AV valves to allow the ventricles to fill again. This sequence ensures efficient blood flow through the heart and into the systemic and pulmonary circulations.

What Does the Cardiac Cycle Reveal About the Opening and Closing