The nodal musculature is autoexcitable. The ability to generate the electrical impulses is shown by all the heart muscles, and it triggers cardiac contraction, which is initiated by the SA node as it generates the maximum number of the action potential. It. It regulates initiating and maintaining the rhythmic contractile activity of the heart. Therefore, the SA node is called the pacemaker of the heart as it regulates the heartbeat. From the SA node, the conduction of impulses moves to the AV node (It lies in the right atrium near the junction of the interauricular and interventricular septum close to the opening of the coronary sinus). The atrio-ventricular bundle is a bundle of nodal fibres which continues from the AVN and passes through the atrio-ventricular septa, and these branches give rise to minute fibres called Purkinje fibres throughout the ventricles. Bundle of His are the Purkinje fibres along with right and left bundles.