This sound is produced during the closure of the semilunar valves.
B: The second heart sound can be represented by dupp. It occurs at the beginning of ventricular diastole and results from the closure of the semilunar valves.
A: The first heart sound can be represented by the syllable lubb. It occurs at the beginning of ventricular systole and results from closure of the AV valves.
lubb
dupp
lubb dupp
lubb duppshhh