question_answer 11)

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

Answer:

Atrioventricular Node (AVN) It is the mass of tissue present in the lower left corner of the right atrium close to the atrioventricular septum. It is stimulated by the impulses that sweep over the atrial myocardium. It is too capable of initiating impulses that cause contraction but at slower rate than SA node. Atrioventricular bundle (AV bundle) It is a bundle of nodal fibres, which continues from AVN and passes through the atriaventricular septa to emerge on the top of interventricular septum. The AV bundle, bundle branches and Purkinje fibres convey impulses of contraction from the AV node to the apex of the myocardium. Here the wave of ventricular contraction begins, then sweeps upwards and outwards, pumping blood into the pulmonary artery and the aorta. This nodal musculature has the ability to generate action potentials without any external stimuli.