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Heart Development - Anatomy & Physiology (view source)
Revision as of 12:01, 28 August 2008
, 12:01, 28 August 2008→Ventricular Outflow Septation
At this stage the ventricles have one common outflow tract, the anterior side of the tract being the Truncus arteriosis and the postierior side being the Conus cordis. A pair of subendothelial swellings appear on either side of the tract and eventually fuse to form a setpum, dividing the outflow tract into an aortic trunk and a pulmonary trunk. The septum takes on a spiral form so that blood from the left ventricle is directed into the aortic trunks and blood from the right is directed into the pulmonary trunk. Initially the septum is composed only of endocardial cells but this is later supplemented by neural crest cells.
At this stage the ventricles have one common outflow tract, the anterior side of the tract being the Truncus arteriosis and the postierior side being the Conus cordis. A pair of subendothelial swellings appear on either side of the tract and eventually fuse to form a setpum, dividing the outflow tract into an aortic trunk and a pulmonary trunk. The septum takes on a spiral form so that blood from the left ventricle is directed into the aortic trunks and blood from the right is directed into the pulmonary trunk. Initially the septum is composed only of endocardial cells but this is later supplemented by neural crest cells.
===The Development of the Semilunar Valves===
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.