What is the function of the atrioventricular valves of the heart?

To make sure blood flows in the right direction.
The purpose of valves is to prevent back flow of blood. In other words, it ensures that blood flows only in one direction .
An atrioventricular (AV) valve is a valve located in the heart between the atria and the ventricles. In the right side of the heart, the AV valve is called the tricuspid valve . On the left side of the heart, the AV valve is called the mitral valve .
The heart is a pump that drives blood throughout the whole circulation. Typical blood flows into the atrium, then into the ventricles and then leaves the heart when the ventricles contract.
The AV valves are designed to close during ventricular contraction so that blood in the ventricles can only leave the heart, instead of flowing back into the atrium.
What can go wrong?
Sometimes the AV valve doesn’t close properly. This creates a situation where blood from the ventricle will flow back into the atrium during heart contractions. This phenomenon is called a regurgitation (e.g. mitral regurgitation, tricuspid regurgitation).