Question
Question: The first heart sound is 口 heard during the:...
The first heart sound is 口 heard during the:
A
Beginning of ventricular systole
B
End of ventricular systole
C
Beginning of atrial systole
D
End of ventricular diastole
Answer
Option 1: Beginning of ventricular systole
Explanation
Solution
The first heart sound (S₁ or “lubb”) occurs at the beginning of ventricular systole due to the closure of the atrioventricular valves.