What is the difference between the structure of the atrioventricular valve and the semi-lunar valves?

The atrioventricular (AV) valves, which include the tricuspid and mitral valves, have a structure that consists of flaps called cusps anchored to the heart wall by chordae tendineae and papillary muscles, which prevent backflow during ventricular contraction. In contrast, the semi-lunar valves, located at the exits of the ventricles (pulmonary and aortic valves), consist of three crescent-shaped cusps without chordae tendineae or papillary muscles, relying instead on the pressure of blood flow to close them. This structural difference reflects their distinct functions in regulating blood flow and preventing backflow in the heart.