What happens to the outflow valves during late diastole?

During late diastole, the heart is in a phase where the ventricles are filling with blood as the atria contract. At this point, the auricular pressure increases and eventually exceeds the ventricular pressure, allowing blood to flow from the atria to the ventricles through the atrioventricular valves, such as the mitral and tricuspid valves.

The outflow valves, which are the aortic and pulmonary valves, are located at the exit of the ventricles. During late diastole, the pressure in the ventricles is lower than the pressure in the great arteries (aorta and pulmonary artery). As a result, the outflow valves must remain closed to prevent any backflow of blood into the ventricles. This closure ensures that the chambers of the heart can properly fill with blood at the end of diastole, preparing for the next phase of the cardiac cycle when the ventricles contract.

Therefore, the statement that the outflow valves close during late diastole accurately reflects the physiological mechanism ensuring efficient heart function. This is essential for maintaining proper circulation and preventing any disruption in blood flow.