During the cardiac cycle, the semilunar valves close during ventricular diastole.

Semilunar Valves

Heart valves located at the exits of the right and left ventricles of the heart, preventing backflow of blood into the ventricles; includes the aortic and pulmonary valves.

Ventricular Diastole

is a phase of the heart cycle during which the ventricles relax and fill with blood following contraction.

Cardiac Cycle

The sequence of events that occur in the heart during one heartbeat, involving contraction and relaxation of the atria and ventricles.