What is the primary role of the AV node in heart rhythm regulation?

The primary role of the AV node in heart rhythm regulation is to conduct impulses from the atria to the ventricles. The AV (atrioventricular) node acts as a critical electrical relay station within the heart's conduction system. After the Sinoatrial (SA) node initiates the heartbeat by generating electrical impulses that spread through the atria, the AV node receives these impulses and briefly delays them before allowing them to pass on to the ventricles. This delay is crucial because it provides the atria sufficient time to contract and fill the ventricles with blood before the ventricles themselves contract. The coordinated timing of this electrical conduction is vital for maintaining an effective heart rhythm and ensuring that blood flows efficiently through the heart and to the rest of the body.

In contrast, while the SA node initiates the heartbeat, it is not the primary role of the AV node. Regulating breathing rates and maintaining blood pressure are functions that fall outside the primary cardiac conduction system's responsibilities and are instead managed by different physiological mechanisms and centers within the body.