Question

Given below are two statements.
Statement I - The heart sound 'Lub' is produced due to simultaneous closure of semilunar valves.
Statement II - The heart sound 'Dub' is produced due to simultaneous closure of cuspid valves.
In the light of above statements, choose the correct option given below:

• A. Both statement I and statement II are correct.
• B. Both statement I and statement II are incorrect.
• C. Statement I is correct but statement II is incorrect.
• D. Statement I is incorrect but statement II is correct.

Hint:

Heart sound trick: Lub = AV valves close, Dub = Semilunar valves close.

Answer 1

The Correct Option is B

Concept:
Heart sounds are produced due to closure of different valves during the cardiac cycle.

Step 1: Understand 'Lub' sound. The first heart sound (Lub) is produced due to closure of:
• Atrioventricular (AV) valves (tricuspid and bicuspid/mitral)

Step 2: Understand 'Dub' sound. The second heart sound (Dub) is produced due to closure of:
• Semilunar valves (aortic and pulmonary)

Step 3: Analyze statements.
• Statement I → Incorrect (Lub is due to AV valves, not semilunar) $\times$
• Statement II → Incorrect (Dub is due to semilunar, not cuspid) $\times$

Step 4: Conclusion. \[ \text{Both statements are incorrect} \]