PHYSIOLOGY
CARDIOVASCULAR PHYSIOLOGY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
aortic and pulmonary semilunar valves closing
|
|
|
tricuspid and bicuspid valves closing
|
|
|
right and left ventricles contracting
|
|
|
tricuspid and bicuspid valves opening
|
Detailed explanation-1: -S2 is produced in part by hemodynamic events immediately following closure of the aortic and pulmonic valves . The vibrations of the second heart sound occur at the end of ventricular contraction and identify the onset of ventricular diastole and the end of mechanical systole.
Detailed explanation-2: -The second heart sound, called S2, makes a “dub” sound caused by the closure of the semilunar (aortic and pulmonary) valves following ventricular systole. S2 is split because aortic valve closure occurs before pulmonary valve closure.
Detailed explanation-3: -The second heart sound (S2) represents closure of the semilunar (aortic and pulmonary) valves (point d). S2 is normally split because the aortic valve (A2) closes before the pulmonary valve (P2). The closing pressure (the diastolic arterial pressure) on the left is 80 mmHg as compared to only 10 mmHg on the right.