What is the primary function of the AV node in the heart's electrical conduction system?

The primary function of the AV node, or atrioventricular node, is to conduct impulses from the atria to the ventricles. This role is critical in the heart’s electrical conduction system, as it serves as a gatekeeper that allows the electrical signal from the atria to pass through to the ventricles only after a slight delay. This delay is essential because it ensures that the atria have time to fully contract and eject blood into the ventricles before those chambers begin to contract themselves.

By conducting impulses in a controlled manner, the AV node helps maintain a coordinated and efficient heartbeat. Without its proper functioning, the timing of heart contractions would be disrupted, potentially leading to ineffective pumping of blood through the heart and out to the body. This contrasts with the role of other structures in the heart; for example, the SA node generates impulses, while the pumping of blood is a function of the heart's muscular chambers, not the electrical conduction pathways. Hormonal influences indeed affect heart rate, but they do not represent the direct conduction functions of the AV node itself.