The semilunar valve of the left side of the heart prevents backflow from the
A) aorta.
B) pulmonary trunk.
C) pulmonary veins.
D) right ventricle.
E) left ventricle.

Question

Quizplus · Accepted Answer

The semilunar valve on the left side of the heart prevents backflow from the aorta, which is the artery that carries oxygen-rich blood from the left ventricle to the entire body. The pulmonary trunk carries deoxygenated blood from the right ventricle to the lungs, so it is not prevented from backflow by the semilunar valve on the left side of the heart. The pulmonary veins carry oxygenated blood from the lungs to the left atrium, so they also do not require a semilunar valve to prevent backflow. The right ventricle pumps deoxygenated blood to the lungs, and so it has a separate semilunar valve to prevent backflow into the right ventricle. Finally, the left ventricle pumps oxygen-rich blood to the body, so it is the chamber that is protected by the semilunar valve on the left side of the heart.

The Semilunar Valve of the Left Side of the Heart