close properly
Blood travels through the bicuspid valve to the left atrium. Both the aortic and the pulmonary valves are semilunar valves. The mitral valve is an atrioventricular valve. Figure 40.17 Varicose veins are veins that become enlarged because the valves no longer close properly, allowing blood to flow backward. Varicose veins are often most prominent on the legs. Why do you think this is the case?.