2nd hea sound is due to
The second is a shoer, high-pitched "dup" (second sound), caused by vibrations associated with the closure of the aoic and pulmonary valves just after the end of ventricular systole.Ref: Ganong&;s Review of medical physiology 25th edition. Page: 542
Closure of AV valves
Closure of aoic valve
Inthrushing of blood
Atrial contraction
Cardiovascular system