The number of action potentials generated by the sino-atrial node $(SAN)$ in a healthy human is $ . . . . . . $ per minute.

The nerve-like modified muscle in the right auricle is known as:

$A$ : Left ventricle pumps blood at a much higher pressure to all body parts involved in systemic circulation.
$R$ : The muscular wall of the left ventricle is two to four times as thick as the wall of the right ventricle.

Where does the bundle of His originate?

Which vertebrate organ receives only oxygenated blood?

$SA$ 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?