Which one of the following is mainly responsible for the second heart sound?
A
Closure of atrioventricular valves
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
Opening of atrioventricular valves
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
Closure of semilunar valves
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
Thrust of blood on ventricular wall during atrial contraction
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is C Closure of semilunar valves Contraction of heart chambers and closure of valves produce “LUB-DUP” sounds during the heartbeat. Contraction of ventricles and closure of atrioventricular valves produces the first heart sound, “lub,” which lasts longest and has a lower pitch.
Relaxation of ventricles and closure of semilunar valves produces the second heart sound, “dup”.
The opening of heart valves and pressure of blood on walls of heart chambers do not produce any heart sound.
The thrust of blood on the ventricular wall during atrial contraction is known as pulse.