Question

Read the following statements and choose the correct option:
A. The first heart sound (lub) is associated with the closure of both semilunar valves.
B. The duration between the adjacent second heart sound and first heart sound is 0.3 seconds
C. The cardiac output is the stroke volume multiplied by the number of heartbeats per minute.

• A. A, B and C are correct
• B. A, C are correct but B is incorrect
• C. A is correct but B, C are incorrect
• D. A, B are incorrect but C is correct

Answer 1

Answer: (D)

The first heart sound (lub) is associated with the closure of the tricuspid and bicuspid valves, which occurs at the beginning of ventricular systole of a cardiac cycle.
The duration between the adjacent second heart sound (dub) and first heart sound (lub) is 0.5 seconds.