Question

The typical Lubb-Dupp (Dubb) sounds heard in the heartbeat of a healthy person are due to:

• A. Closing of the tricuspid and bicuspid valves
• B. Blood flow through the aorta
• C. Closing of the tricuspid and semilunar valves
• D. Closing of the semilunar valves

Answer 1

The correct option is C Closing of the tricuspid and semilunar valves

The typical Lubb-Dupp (Dubb) sounds heard in the heartbeat of a healthy person are due to the closure of the atrioventricular (tricuspid and bicuspid/mitral) valves and semilunar valves. 'Lubb' is the first sound of heart. During this sound, ventricles contract and atrioventricular valves close. 'Dupp' can be heard next and during this sound, ventricles relax and aortic-pulmonary valves are close. The time period between the first and second sound of heart defines systole and the time period between the second and first sound defines diastole.

So, the correct answer is option C.