Question

Typical lub-dub sounds in heart beat are due to

• A. Closing of bicuspid and tricuspid valve
• B. Closing of semi-lunar valve
• C. Blood under pressure through aorta
• D. Closure of bicuspid -tricuspid valve followed by semi-lunar valves

Answer 1

The correct option is D Closure of bicuspid -tricuspid valve followed by semi-lunar valves

In healthy adults, there are two normal heart sounds often described as a lub and a dub, that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the AV valves (the mitral valve and the tricuspid valve) and semilunar valves (the pulmonary valve and the aortic valve), respectively.

So, the correct answer is option D.