Question
The first heart sound is produced when :
diastole begins
semilunar valve close quickly
interventricular pressure decreases
bicuspid and tricuspid valve close quickly
Solution
D.
bicuspid and tricuspid valve close quickly
First heart sound 'lubb' is low pitched and of long duration, which produced by tight closure of bicuspid and tricuspid valve at the start of ventricular contraction.
