What causes the delay in conduction at the AV node?

The delay in conduction at the atrioventricular (AV) node is primarily due to the unique properties of the nodal tissue, which involves both sodium and calcium channels.

In the cardiac conduction system, the AV node acts as a critical interface between the atria and ventricles. This delay is essential for allowing sufficient time for the atria to contract and complete filling of the ventricles with blood before they also contract.

Calcium channels play a significant role in the slow response action potentials found in the AV node. Unlike the rapid depolarization seen in other cardiac tissues that primarily rely on sodium influx, the AV node has a slower rate of depolarization, which is largely governed by calcium influx. This calcium-induced delayed conduction allows the AV node to efficiently manage the timing of electrical impulses.

Sodium channels also contribute to the conduction process, but their role is mainly in the initial phase of depolarization. The gradual increase in calcium conductance, in conjunction with slower sodium influx, leads to a prolonged refractory period and reduced conduction velocity in the AV node compared to other parts of the conduction system.

The combination of both sodium and calcium channels' effects on action potentials in the AV node is essential for its unique function, making the understanding