Glycocalyx
| Glycocalyx | |
|---|---|
| Identifiers | |
| MeSH | Glycocalyx |
| Code | TH H1.00.01.1.00002 |
| TH | H1.00.01.1.00002 |
| FMA | 66838 |
|
Anatomical terminology
[]
|
|
The glycocalyx is a glycoprotein-polysaccharide covering that surrounds the cell membranes of some bacteria, epithelia and other cells.
Most animal epithelial cells have a fuzz-like coat on the external surface of their plasma membranes. This coating consists of several carbohydrate moieties of membrane glycolipids and glycoproteins, which serve as backbone molecules for support. Generally, the carbohydrate portion of the glycolipids found on the surface of plasma membranes helps these molecules contribute to cell-cell recognition, communication, and intercellular adhesion.
The glycocalyx is a type of identifier that the body uses to distinguish between its own healthy cells and transplanted tissues, diseased cells, or invading organisms. Included in the glycocalyx are cell-adhesion molecules that enable cells to adhere to each other and guide the movement of cells during embryonic development. The glycocalyx plays a major role in regulation of endothelial vascular tissue, including the modulation of red blood cell volume in capillaries.
The slime on the outside of a fish is an example of glycocalyx. The term was initially applied to the polysaccharide matrix coating epithelial cells, but its functions have been discovered to go well beyond that.
The glycocalyx is located on the apical surface of vascular endothelial cells which line the lumen. When vessels are stained with cationic dyes such as Alcian blue stain, transmission electron microscopy shows a small, irregularly shaped layer extending approximately 50–100 nm into the lumen of a blood vessel. Another study used cryo-transmission electron microscopy and showed that the endothelial glycocalyx could be up to 11μm thick. It is present throughout a diverse range of microvascular beds (capillaries) and macrovessels (arteries and veins). The glycocalyx also consists of a wide range of enzymes and proteins that regulate leukocyte and thrombocyte adherence, since its principal role in the vasculature is to maintain plasma and vessel wall homeostasis. These enzymes and proteins include:
...
Wikipedia