Question

Lub sound produced during heart beat is caused by

• A. ventricular diastole
• B. ventricular systole
• C. atrial diastole
• D. atrial systole

Answer 1

Answer: (B)

ventricular systole

Answer 2

Lubb ($S_{1}$, first sound, systolic sound) is the first heart sound which is louder or low pitched, of long duration ($0.16-0.19$ seconds) and is produced due to closure of atrioventricular valves (tricuspid and bicuspid) during ventricular systole.