Endocardial cushions, or atrioventricular cushions, refer to a subset of cells in the

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...

of the heart that play a vital role in the proper formation of the heart

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five c ...

. They develop on the

atrioventricular canal The proper development of the atrioventricular canal into its prospective components (The heart septum and associated valves) to create a clear division between the four compartments of the heart and ensure proper blood movement through the heart, ...

and conotruncal region of the bulbus cordis. During

heart development Heart development, also known as cardiogenesis, refers to the prenatal development of the heart. This begins with the formation of two endocardial tubes which merge to form the tubular heart, also called the primitive heart tube. The heart is the ...

, the heart starts out as a tube. As heart development continues, this tube undergoes 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 primitive valves and

, critical to the proper formation of a four-chambered heart.

Development

The

endocardial The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the endothelial cells that line blood vessels. The endocardium also provides protection to the val ...

cushions are thought to arise from a subset of

endothelial The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the ve ...

cells that undergo epithelial-mesenchymal transition, a process whereby these cells break cell-to-cell contacts and migrate into the cardiac jelly (towards the interior of the heart tube). These migrated cells form the "swellings" called the endocardial cushions seen in the heart tube. Upon sectioning of the heart the atrioventricular endocardial cushions can be observed in the lumen of the

atrial canal The proper development of the atrioventricular canal into its prospective components (The heart septum and associated Heart valve, valves) to create a clear division between the four compartments of the heart and ensure proper blood movement throug ...

as two thickenings, one on its dorsal and another on its ventral wall. These thickenings will go on to fuse and remodel to eventually form the valves and septa of the mature adult heart.

Clinical significance

A problem in endocardial cushion development or remodeling is thought to be associated with

atrioventricular septal defect Atrioventricular septal defect (AVSD) or atrioventricular canal defect (AVCD), also known as "common atrioventricular canal" (CAVC) or " endocardial cushion defect" (ECD), is characterized by a deficiency of the atrioventricular septum of the hea ...

References

External links

* *
Overview at mcgill.ca

from the

University of Toronto The University of Toronto (UToronto or U of T) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution ...

{{Authority control Embryology of cardiovascular system

Development

Clinical significance

See also

References

External links