The pacemaker of the human heart is: (a) SA node (b) Tricuspid valve (c) AV node (d) All of these
Option A. The SA node is the heart's natural pacemaker. The SA node consists of a cluster of cells that are situated in the upper part of the wall of the right atrium (the right upper chamber of the heart). The electrical impulses are generated there. The SA node is also called the sinus node.
