What is the first stage in the conduction pathway of the heart?

The first stage in the conduction pathway of the heart is when the sinoatrial (SA) node fires. The SA node, commonly referred to as the heart's natural pacemaker, is responsible for initiating the electrical impulses that regulate the heartbeat. When the SA node fires, it generates an electrical impulse that causes the atria to contract, pushing blood into the ventricles.

This initial electrical impulse sets the rhythm of the heart and is crucial for maintaining a coordinated heart rhythm. Following this, the impulse travels to the atrioventricular (AV) node, then to the Bundle of His, and finally along the Purkinje fibers, leading to ventricular contraction. Each step follows the initial action of the SA node, but the firing of the SA node is the essential starting point of the conduction pathway. Understanding this sequence is fundamental to grasping how the heart beats effectively.