Which valves are located between the ventricles and the arteries (the pulmonary artery and the aorta)?

• A. Vena Cava
• B. Semilunar Valves
• C. Aorta
• D. Pulmonary Veins

Answer: (B)

Valves between the ventricles and the arteries are the semilunar valves. They sit at the exit of each ventricle: the aortic valve between the left ventricle and the aorta, and the pulmonary valve between the right ventricle and the pulmonary artery. Their crescent-shaped cusps form a tight seal when closed, preventing backflow into the ventricles as the heart relaxes. They open during ventricular contraction (systole) to allow blood to flow into the arteries and snap shut during relaxation (diastole) to stop regurgitation. The other options aren’t valves at the ventricular outflow: vena cava and pulmonary veins are vessels returning blood to the heart, and the aorta is a vessel, not a valve.