Question

The first heart sound (lub) is associated with:

• A. Opening of pulmonary and tricuspid valves
• B. Closure of bicuspid and aortic valves.
• C. Closure of the tricuspid and bicuspid valves.
• D. Opening of the tricuspid and bicuspid valves.

Answer 1

The correct option is C Closure of the tricuspid and bicuspid valves.

During each cardiac cycle two prominent sounds are produced - lub and dub. The first heart sound (lub) is associated with the closure of the tricuspid and bicuspid valves whereas the second heart sound (dub) is associated with the closure of the semilunar valves.