What is the significance of the atrio-ventricular node and atrio-ventricular bundle in the functioning of the heart?

(N/A) The atrioventricular $(AV)$ node is located in the right atrium,near the base of the inter-auricular septum. It acts as a relay station for cardiac impulses.
It gives rise to the atrioventricular bundle (bundle of $His$),which conducts cardiac impulses from the atria to the ventricles.
As the bundle of $His$ passes along the interventricular septum,it divides into right and left branches.
The terminal branches of this system form a network of Purkinje fibres that penetrate the myocardium.
The wave of excitation initiated by the sino-atrial node ($SA$ node) stimulates the $AV$ node,which then transmits the impulse through the bundle of $His$ and Purkinje fibres to trigger ventricular contraction.
Thus,the $AV$ node and $AV$ bundle are essential for the coordinated contraction of the ventricles.