In humans, blood passes from the post caval to the diastolic right atrium of heart due to:

Explanation

Blood passes from the post caval to the diastolic right atrium of the heart due to the pressure difference between the two chambers. The post caval is a large vein that carries deoxygenated blood from the lower body to the right atrium of the heart. The right atrium is a chamber of the heart that receives deoxygenated blood from the post caval and the upper body. The pressure in the post caval is higher than the pressure in the right atrium. This pressure difference causes blood to flow from the post caval to the right atrium.The blood then flows from the right atrium to the right ventricle, which pumps it to the lungs to be oxygenated. It is true that in humans, blood passes from the postcava to the diastolic right atrium of the heart due to the pushing open of the venous valves. The postcava is a large vein that carries deoxygenated blood from the lower body to the right atrium of the heart. The right atrium is the upper chamber of the right side of the heart. It receives deoxygenated blood from the postcava and the superior vena cava. The venous valves are located in the postcava and other veins that drain into the heart. These valves prevent backflow of blood when the heart contracts. When the heart relaxes, the venous valves open and allow blood to flow into the right atrium. The pushing open of the venous valves is caused by the difference in pressure between the blood in the postcava and the blood in the right atrium. The blood in the postcava is under higher pressure than the blood in the right atrium. This pressure difference causes the venous valves to open and allow blood to flow into the right atrium.