Which structure is known as the pace setter of the heart?

The structure known as the pace setter of the heart is the sinoatrial (SA) node. This specialized cluster of cells is located in the right atrium and is primarily responsible for initiating the electrical impulses that regulate the heartbeat. The SA node generates action potentials at a regular rate, translating them into rhythmic heartbeats. This activity serves as the primary driver of the heart’s rhythm, typically setting a pace of about 60 to 100 beats per minute in a resting state.

The intrinsic pacemaking activity of the SA node influences both the atria and, subsequently, the ventricles, as its impulses spread through the heart's conduction system. While other structures like the atrioventricular (AV) node, the Bundle of His, and the Purkinje fibers play vital roles in the conduction pathway and help synchronize the heartbeat, they do not initiate the electrical impulses like the SA node does. Therefore, recognizing the SA node as the primary pacemaker is crucial for understanding cardiac electrophysiology.