1. Sinoatrial (SA) Node: This is the heart's natural pacemaker, located in the right atrium. It initiates the electrical impulse that triggers each heartbeat.
2. Atrial Myocardium: The impulse spreads rapidly through the atrial muscle, causing the atria to contract and pump blood into the ventricles.
3. Atrioventricular (AV) Node: The impulse reaches the AV node, located near the junction of the atria and ventricles. The AV node slows down the impulse slightly, allowing the ventricles to fill with blood.
4. Bundle of His: L'impulsion se déplace à travers le paquet de son, une bande spécialisée de fibres qui s'étend du nœud AV dans le septum interventriculaire (la paroi entre les ventricules).
5. Right and Left Bundle Branches: The Bundle of His divides into the right and left bundle branches, which carry the impulse to the ventricles.
6. Purkinje Fibers: Les branches du faisceau se divisent davantage en un réseau de fibres fines appelées fibres de Purkinje, qui distribuent l'impulsion dans tout le myocarde ventriculaire.
7. Ventricular Myocardium: The impulse stimulates the ventricular muscle, causing it to contract and pump blood out of the heart.
Simplified:
* SA Node (Pacemaker) -> Atria -> AV Node -> Bundle of His -> Bundle Branches -> Purkinje Fibers -> Ventricles
This organized sequence ensures that the heart contracts in a coordinated way, effectively pumping blood throughout the body.
