Endocardial cushions
Encyclopedia
Atrioventricular cushions or endocardial cushions refers to a subset of cells in the primordial heart that play a vital role in proper heart septation.
They develop on the atrioventricular canal.
During development the heart starts out as a tube. As heart development continues this tube undergoes conformational changes and remodeling to eventually form the four-chambered heart. The endocardial cushions are a subset of cells found in the developing heart tube that will give rise to the heart's valves and septa critical to the proper formation of a four-chambered heart.
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Upon sectioning of the heart the atrioventricular cushions can be observed in the lumen of the atrial canal
as two thickenings, one on its dorsal and another on its ventral wall. These thickenings or endocardial cushions will go on to fuse and remodel to eventually form the valves and septa of the mature adult heart.
They develop on the atrioventricular canal.
During development the heart starts out as a tube. As heart development continues this tube undergoes conformational changes and remodeling to eventually form the four-chambered heart. The endocardial cushions are a subset of cells found in the developing heart tube that will give rise to the heart's valves and septa critical to the proper formation of a four-chambered heart.
Clinical significance
A problem in endocardial cushion development or remodeling is thought to be associated with atrioventricular septal defectAtrioventricular septal defect
Atrioventricular septal defect or atrioventricular canal defect , previously known as "common atrioventricular canal" or "endocardial cushion defect", is characterized by a deficiency of the atrioventricular septum of the heart...
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Development
The endocardial cushions are thought to arise from a subset of endothelial cells that undergo epithelial to mesenchymal transformation, a process whereby these cells break cell-to-cell contacts and migrate into the cardiac jelly (towards to interior of the heart tube). These migrated cells form the "swelling" seen in the heart tube that is termed endocardial cushionsUpon sectioning of the heart the atrioventricular cushions can be observed in the lumen of the atrial canal
Atrial canal
In the developing heart, the constriction between the atrium and ventricle constitutes the atrioventricular canal or atrial canal, and indicates the site of the future atrioventricular valves.-External links:*...
as two thickenings, one on its dorsal and another on its ventral wall. These thickenings or endocardial cushions will go on to fuse and remodel to eventually form the valves and septa of the mature adult heart.
External links
- Overview at mcgill.ca
- 3d animation of heart development from the University of TorontoUniversity of TorontoThe University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...