What is the primary function of the sinoatrial node?

The sinoatrial (SA) node is often referred to as the natural pacemaker of the heart. Its primary function is to control heart rate by generating electrical impulses that initiate each heartbeat. This electrical activity spreads through the heart muscles, causing them to contract in a coordinated manner, which effectively pumps blood throughout the body.

The SA node's ability to set the rhythm of the heart is crucial for maintaining a consistent and appropriate heart rate, which ensures that the body receives adequate blood supply to meet its metabolic demands. While other options like regulating blood flow may involve heart function, it is the SA node's specific role in generating impulses that directly correlates with controlling how fast or slow the heart beats.