11. What is the significance of the atrioventricular node and atrioventricular bundle in the functioning of the heart?
The atrioventricular (AV) node is present in the right atrium, near the base of the interauricular septum that separates the right auricle from the ventricle. It gives rise to the bundle of His that conducts the cardiac impulses from the auricles to the ventricles. As the bundle of His passes the ventricle along the inter-ventricular septum, it divides into two branches – the right ventricle and the left ventricle. The end branches of this conducting system then form a network of Purkinje fibers that penetrate into the myocardium. The auricular contraction initiated by the wave of excitation from the sinoatrial node (SA node) stimulates the atrioventricular node, thereby leading to the contraction of ventricles through the bundle of His and Purkinje fibers. Hence, the atrioventricular node and the atrioventricular bundle play a role in the contraction of ventricles.
