ANATOMY

Detailed explanation-1: -The aortic valve permits the movement of the blood in one direction from the left ventricle into arteries. Therefore, when the left semilunar valve is closed, the blood cannot go back into the ventricle. The pulmonary vessel is found between the right ventricle and the pulmonary artery.

Detailed explanation-2: -Valves are actually flaps (leaflets) that act as one-way inlets for blood coming into a ventricle and one-way outlets for blood leaving a ventricle. Normal valves have 3 flaps (leaflets), except the mitral valve.

Detailed explanation-3: -return is prevented by the semilunar valves, which consist of membranous saclike flaps that open away from the heart. If the flow of blood reverses, the flaps fill and are pressed against each other, thus blocking the reentry of blood into the aorta.

Detailed explanation-4: -Veins have valves which allow blood to flow only in one direction.

Detailed explanation-5: -The blood that is meant to leave the ventricles to travel to the body is supposed to be prevented from flowing in the wrong direction by the parts of the aortic and pulmonary valves called the cusps. The cusps help the valves create a tight seal, which helps blood flow in the correct direction.