The 'Heart of Heart' is:

Match the following columns:

Column-$I$	Column-$II$
$a$. Superior Vena Cava	$p$. Carries deoxygenated blood towards the lungs
$b$. Inferior Vena Cava	$q$. Carries oxygenated blood away from the lungs
$c$. Pulmonary Artery	$r$. Brings deoxygenated blood from lower body parts to the right atrium
$d$. Pulmonary Vein	$s$. Brings deoxygenated blood from upper body parts to the right atrium

How much of the total blood volume is present in the heart (in $\%$)?

The cardiac pacemaker in a patient fails to function normally. The doctors find that an artificial pacemaker is to be grafted in him. It is likely that it will be grafted at the site of

The systemic aorta arises from which of the following?

The thread-like tendons of papillary muscles inserted upon the flaps of tricuspid and bicuspid valves are: