Question

The first heart sound is

• A. ‘Lubb’ at the end of ventricular systole
• B. ‘Dup’ at the end of ventricular systole
• C. ‘Lubb’ at the beginning of ventricular systole
• D. ‘Dup’ at the beginning of ventricular systole.

Answer 1

The correct option is C

‘Lubb’ at the beginning of ventricular systole

First and second heart sounds are produced when the AV vlaves and semilunar valves closes respectively at the beginning of ventricular systole and ventricular diastole respectively.