What is the function of the atrioventricular (AV) node?

The atrioventricular (AV) node serves a crucial role in the cardiac conduction system by acting as a gatekeeper between the atria and the ventricles. Its primary function is to delay the electrical impulse received from the atria before passing it on to the ventricles. This delay is vital for ensuring that the atria have sufficient time to contract and pump blood into the ventricles before they contract. Without this delay, the heart would not function effectively, as the chambers would not have the opportunity to fill properly.

This delay is particularly important during normal sinus rhythm, where the SA node generates impulses at a regular rate. The AV node's ability to create a pause ensures coordinated and effective heart contractions, optimizing blood flow throughout the body. In scenarios of increased heart rate or physical activity, while the AV node does play a role in heart rate management, its main function remains focused on the electrical impulse transmission and delay rather than on generating impulses or coordinating simultaneous contractions of the atria and ventricles.