What is the primary pacemaker of the heart called?

The primary pacemaker of the heart is referred to as the sinoatrial node. This specialized group of cells is located in the right atrium and is responsible for initiating the electrical impulses that determine the heart's rhythm. It generates these impulses at a regular pace, which triggers the contraction of the heart muscles and, thus, regulates heart rate.

The sinoatrial node is often called the heart’s natural pacemaker; it sets the pace for the entire cardiac cycle. Because of its dominant role in controlling the heart rate, it ensures that the heart beats in a coordinated and efficient manner, supporting proper blood circulation throughout the body.

Other structures, such as the atrioventricular node, the Bundle of His, and the Purkinje fibers, play important roles in conducting impulses through the heart but do not initiate the rhythm. The atrioventricular node acts as a gatekeeper that slows down the electrical signal before it reaches the ventricles, while the Bundle of His and Purkinje fibers distribute the electrical impulse throughout the ventricles for coordinated contraction. However, none of these structures can replicate the pacing function of the sinoatrial node, reaffirming its status as the primary pacemaker.