Endocardial cushions, or atrioventricular cushions, refer to a subset of cells in the
development
Development or developing may refer to:
Arts
*Development (music), the process by which thematic material is reshaped
* Photographic development
*Filmmaking, development phase, including finance and budgeting
* Development hell, when a proje ...
of the heart that play a vital role in the proper formation of the heart
septa
SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...
.
They develop on the
atrioventricular canal Atrioventricular (having to do with an Atrium (anatomy), atrium and Ventricle (heart), ventricle) can refer to:
*Left atrioventricular opening
*Atrioventricular fistula
*Atrioventricular node
*Atrioventricular valves, the mitral valve and tricuspid ...
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 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
septa
SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...
, critical to the proper formation of a four-chambered heart.
Development
The
endocardial
The endocardium (: endocardia) 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 prote ...
cushions are thought to arise from a subset of
endothelial
The endothelium (: endothelia) 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 res ...
cells that undergo
epithelial-mesenchymal transition, a process whereby these cells break cell-to-cell contacts and migrate into the
cardiac jelly
The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...
(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 atrium (; : atria) is one of the two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular mitral and tricuspid heart valves.
...
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" or "endocardial cushion defect" (ECD), is characterized by a deficiency of the atrioventricular septum of the heart that c ...
.
See also
*
Endocardial tubes The endocardial tubes are paired regions in the embryo that appear in its ventral pole by the middle of the third week of gestation and consist of precursor cells for the development of the embryonic heart. The endocardial heart tubes derive from t ...
*
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 ...
*
Mesenchyme
Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood, or bone. The interactions between mesenchyme and epithelium help to form nearly ever ...
References
External links
*
*
Overview at mcgill.cafrom the
University of Toronto
The University of Toronto (UToronto or U of T) is a public university, public research university whose main campus is located on the grounds that surround Queen's Park (Toronto), Queen's Park in Toronto, Ontario, Canada. It was founded by ...
{{Authority control
Embryology of cardiovascular system