Question

Why is the lubb and dup sound can be heard?

Answer 1

The lubb and dup sounds of heart are monitored by the stethoscope. The first sound comes due to the closure of the the atrio-ventricular valves. It occurs at the onset of ventricular systole. The second sound of dup is of high pitch. It is caused by the closure of the semilunar valves in the pulmonary artery and the aorta. It occurs at the onset of ventricular diastole.