1. Sinoatrial (SA) Node: The pacemaker of the heart, located in the right atrial wall near the superior vena cava. It initiates the electrical impulse that triggers each heartbeat.
2. Internodal Pathways: These pathways conduct the impulse from the SA node to the atrioventricular (AV) node.
3. Atrioventricular (AV) Node: Located in the interatrial septum, just above the tricuspid valve. This node slightly delays the impulse, allowing the atria to contract before the ventricles.
4. Bundle of His: A bundle of specialized conducting fibers that extends from the AV node down into the interventricular septum.
5. Right and Left Bundle Branches: The bundle of His divides into these branches, which conduct the impulse to the right and left ventricles respectively.
6. Purkinje Fibers: A network of fine fibers that spread throughout the ventricular walls, ensuring that the impulse reaches all parts of the ventricles, causing them to contract.
This sequence of events ensures a coordinated and efficient contraction of the heart chambers, pumping blood throughout the body.
