The<unk>  or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, and conducts the normal electrical impulse from the atria to the ventricles. The AV node is quite compact (~1 x 3 x 5 mm).
Atrioventricular node
Node of Ranvier
Heart valve
Cardiopulmonary nerves
Vasa vasorum
Endobronchial valve
Coronary
Sternal saw