In humans,the volume of blood pumped out by each ventricle per minute is

What happens during diastole in the cardiac cycle?

Systole $= ....P.....,$ Diastole $= .....Q....$
$P \quad Q$

$A$: Isovolumetric systole of a normal cardiac cycle is responsible for the opening of semilunar valves causing the blood flow into aortic aorta and pulmonary aorta.
$R$: During isovolumetric systole,intraventricular pressure increases as semilunar and $AV$ valves are closed and ventricles are contracting.

Doctors use a stethoscope to hear the sounds produced during each cardiac cycle. The second heart sound is heard when:

The first heart sound '$Lubb$' occurs in which phase of the cardiac cycle?