The $Bundle$ $of$ $His$ are:

Purkinje's fibres are special types of

The first heart sound is

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

$SA$ node (Sinoatrial node) ke baare mein sahi kathan chuniye:
$I$. Located at the right upper corner of the right atrium.
$II$. Heart of heart.
$III$. It initiates the rhythmic contractile activity of the heart.
$IV$. It is called the pace-keeper of the heart.
$V$. It is called the pacemaker of the heart.
Which of the following options contains the correct statements?

Thrombosis in which coronary artery is met most frequently in?