Question: what is the difference between av valves and semilunar valves?
Answer: The valves between the atria and ventricles are called atrioventricular valves (also called cuspid valves), while those at the bases of the large vessels leaving the ventricles are called semilunar valves. ... When the ventricles relax, semilunar valves close to prevent blood from flowing back into the ventricles.