Answer:
It allows the pumping of blood upwards towards the respective blood vessel from each ventricle.
Explanation:
From the right ventricle, blood is pumped upwards into the pulmonary artery while the left ventricle pumps the blood upwards into the aorta. The contraction of the ventricle starts at the apex and moves upwards to pump the blood from the left and right ventricle into the aorta and pulmonary artery respectively.
The aortic and pulmonary valves are called semilunar valves. As the blood pressure in ventricles exceeds the pressure in the aorta and pulmonary arteries, the semilunar valves are opened and blood is pumped into respective arteries.