Which heart sound is associated with the closure of semilunar valves?

The heart sound associated with the closure of the semilunar valves is referred to as "Dub." This sound occurs at the end of ventricular systole when the blood has been ejected from the ventricles into the aorta and pulmonary artery. As the ventricles relax, the pressure drops, causing the semilunar valves (the aortic and pulmonary valves) to close, which produces the "Dub" sound. This sound is termed S2 in the cardiac cycle, and it signifies the end of one phase of the heartbeat and the beginning of diastole, when the heart chambers fill with blood again. Understanding this sound is crucial for recognizing normal and abnormal heart function during assessments or examinations.