When do the atrioventricular valves open?

When do the atrioventricular valves open?

• A. When atrial pressure is greater than ventricular pressure
• B. When the ventricles are contracting
• C. During ventricular diastole
• D. When the atria relax and the AV valves open

Answer: (A)

The opening of the atrioventricular valves depends on the pressure difference between the atria and the ventricles. They open when atrial pressure exceeds ventricular pressure, allowing blood to flow from the atria into the ventricles during ventricular filling in diastole. When the ventricles contract, ventricular pressure rises above atrial pressure, closing the AV valves to prevent backflow. Later, as the ventricles relax and pressure falls below atrial pressure, the AV valves reopen to permit continued filling, with the atria possibly contracting to top up ventricular volume.

The opening of the atrioventricular valves depends on the pressure difference between the atria and the ventricles. They open when atrial pressure exceeds ventricular pressure, allowing blood to flow from the atria into the ventricles during ventricular filling in diastole. When the ventricles contract, ventricular pressure rises above atrial pressure, closing the AV valves to prevent backflow. Later, as the ventricles relax and pressure falls below atrial pressure, the AV valves reopen to permit continued filling, with the atria possibly contracting to top up ventricular volume.