What is the function of atria ventricular node?

The atrioventricular node (AV node) is a specialized group of cells located in the right atrium of the heart. It serves as the main electrical connection between the atria (upper chambers) and ventricles (lower chambers) of the heart. The primary function of the AV node is to delay electrical signals before they reach the ventricles, ensuring a coordinated contraction of the heart chambers. Here are the key functions of the atrioventricular node:

1. Delay of Electrical Signals: The AV node delays the electrical impulses generated by the sinoatrial node (SA node), which is the natural pacemaker of the heart. This delay allows the atria to fill with blood before the ventricles contract. The slight pause created by the AV node ensures that the atria have sufficient time to complete their filling phase, maximizing the ventricular filling volume and stroke output.

2. Coordination of Atrial and Ventricular Contractions: By delaying the electrical signals, the AV node ensures a sequential contraction of the heart chambers. The atria contract first, pushing blood into the ventricles. The delayed signal then reaches the ventricles, causing them to contract and pump blood out to the body. This coordination prevents the ventricles from contracting prematurely, ensuring a more efficient pumping action of the heart.

3. Atrioventricular Block: In certain cases, the AV node can develop a malfunction called atrioventricular block, where the electrical signals are partially or completely blocked from passing through the node. This can lead to arrhythmias, such as bradycardia (slow heart rate) or complete heart block.

4. Protection Against Rapid Heart Rates: The AV node acts as a natural filter, slowing down excessively fast electrical signals. This prevents the ventricles from responding to very rapid atrial rates, such as those that occur during atrial fibrillation. By delaying the impulses, the AV node helps maintain a regular and coordinated heart rhythm.

Overall, the atrioventricular node plays a crucial role in coordinating the electrical activity between the atria and ventricles, ensuring a synchronized and efficient pumping of blood throughout the body.