What is the primary function of the AV node in the heart?

The primary function of the AV node is indeed to delay the impulse from the SA node. The atrioventricular (AV) node serves as a critical relay point in the heart's electrical conduction system. When the sinoatrial (SA) node, which is located in the right atrium, generates an electrical impulse, that impulse travels rapidly through the atria, leading to atrial contraction.

However, the AV node introduces a necessary delay in the transmission of the impulse to the ventricles. This delay allows the atria to fully contract and push blood into the ventricles before the ventricles are stimulated to contract. Without this delay, the atria and ventricles could contract simultaneously, which would reduce the efficiency of blood flow through the heart and into the circulatory system.

Thus, the delay facilitated by the AV node is crucial for maintaining a coordinated and effective heartbeat.