Describe and explain the events that occur in full contraction of the heart

-To start the sinoatrial node (SAN) on the wall of the right atrium sends an electrical signal across the right and left atria to contract and the blood moves into the ventricles. A layer of non-conductive tissue stops the electrical signal from crossing to the ventricles. The electrical signal then enters the atrioventricular node (AVN) which is positioned between the atria. The AVN, after a short delay, sends an electrical signal down the Purkyne tissue of the bundle of HIs. The bundle of His carries the signal down the septum of the ventricles to the apex and causes the ventricles contract at the same time.