Changes

The semiluanr valves prevent blood from flowing from the aortic and pulmonary trunks back into the ventricles. They form after septation of the outflow tract occurs. The endocardium swells in three places at the origins of the aortic and pulmonary trunks, these swellings grow towards each other but never fuse. The swellings form shelf like projections which are then remolled to form three thin walled cusps, which prevent back flow.

The semiluanr valves prevent blood from flowing from the aortic and pulmonary trunks back into the ventricles. They form after septation of the outflow tract occurs. The endocardium swells in three places at the origins of the aortic and pulmonary trunks, these swellings grow towards each other but never fuse. The swellings form shelf like projections which are then remolled to form three thin walled cusps, which prevent back flow.