<P> The aortic and pulmonary valves are located at the base of the aorta and the pulmonary trunk respectively . These are also called the `` semilunar valves '' . These two arteries receive blood from the ventricles and their semilunar valves permit blood to be forced into the arteries , and prevent backflow from the arteries into the ventricles . These valves do not have chordae tendineae , and are more similar to the valves in veins than they are to the atrioventricular valves . The closure of the semilunar valves causes the second heart sound . </P>
<P> The aortic and pulmonary valves are located at the base of the aorta and the pulmonary trunk respectively . These are also called the `` semilunar valves '' . These two arteries receive blood from the ventricles and their semilunar valves permit blood to be forced into the arteries , and prevent backflow from the arteries into the ventricles . These valves do not have chordae tendineae , and are more similar to the valves in veins than they are to the atrioventricular valves . The closure of the semilunar valves causes the second heart sound . </P>
where are the semilunar valves located in the aorta
where are the semilunar valves located in the aorta
base
base