MICROANATOMY

Detailed explanation-1: -The SA node starts the sequence by causing the atrial muscles to contract. That’s why doctors sometimes call it the anatomical pacemaker. Next, the signal travels to the AV node, through the bundle of HIS, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract.

Detailed explanation-2: -The electrical impulse travels from the sinus node to the atrioventricular node (also called AV node). There, impulses are slowed down for a very short period, then continue down the conduction pathway via the bundle of His into the ventricles.

Detailed explanation-3: -The SA (sinoatrial) node generates an electrical signal that causes the upper heart chambers (atria) to contract. The signal then passes through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing them to contract, or pump. The SA node is considered the pacemaker of the heart.

Detailed explanation-4: -The impulse leaves the sinus node and travels a set path through the upper chambers, the atria, causing them to contract and squeeze blood into the lower chambers. The electrical signal then reaches the atrioventricular (AV) node. The AV node is in the middle of the heart, between the atrium and the ventricle.

Detailed explanation-5: -The sino-atrial (SA) node. The atrio-ventricular (AV) node. The bundle of His. The left and right bundle branches. The Purkinje fibres.