What is the primary function of the SA node?

The primary function of the SA node, or sinoatrial node, is to initiate the heartbeat. Located in the right atrium of the heart, the SA node acts as the natural pacemaker, generating electrical impulses that trigger the cardiac cycle. These impulses spread throughout the atria, causing them to contract and pump blood into the ventricles. This automatic initiation of electrical activity is crucial for maintaining a regular heart rhythm and ensuring that the heart beats in a coordinated manner.

The SA node's role in starting the heartbeat is fundamental to the heart's function, as it sets the pace at which the heart beats. Without the SA node's ability to generate impulses, the heart would not contract effectively, and blood flow would be significantly compromised. Thus, understanding the SA node's role is essential in the study of cardiovascular physiology and EKG interpretation.