List of abbreviations

Vocabulary of micros- copic anatomy specialist terms explained in English + German

Every attempt was made to provide correct information and labelling, however any liability for eventual errors or incompleteness is rejected!

dieser Seite Editor: Dr. med. H. Jastrow

Conditions of use

microvilli with glycocalyx (monkey)	other microvill with glycocalyx (monkey)	cross-sectioned microvilli with glycocalyx (monkey)	glycocalyx of an ente- rocyte in the colon (rat)

microvilli + glycocalyx human pharyngeal tonsil	overview thereof	glycocalyx covered microvilli human pharyngeal tonsil	glycocalyx covered microvilli of the human pharyngeal tonsil

The cell surface coat, i.e. the glycocalyx (Terminologia histologica: Glycocalyx) summarizes all sugar molecules which are bound to cell-surface proteins or -phopholipids on the outer cell membrane. The name derives from the Greek words glykos (sugar) and kalyx (coat) but not from Latin calix (goblet). Common staining and contrastation in electron microscopy using osmiumtetroxide shows the glycocalyx as mesh- or network of moderate electron-density sprouting off the outer lamella of the cell membrane into surrounding space. Application or ruthenium red results in a more intense staining. Glycolipids reach from the outer lamella of the cell membrane towards the extracellular space and bind different sugars of intermediate size (oligosaccharids) with varying chain lengths as well as sugar derived acids (sialic acids) in this region. Glucose, Galactose, Fucose, N-Acetyl-Glukosamin, N-Acetyl-Galaktosamin and N-Acetyl-Neuraminsäure are the most important sugar components of the glycocalyx. Further proteins which are integrated into the cell membrane (glycoproteins, proteoglycans) extend considerably towards the extracellular space where they attach shorter oligosaccharid- or longer glycan chains. The presence of multiple anionic components like sulfated glycosaminoglycans or sialic acids bound to such chains is the reason for the negative charge of the cell surface. Further components of the glycocalyx are the long extracellular portions of mucins, especially the tans membrane protein mucin-1 and large sugar proteins of mucus which are also secreted by glandular cells like the goblet cells of the colon.
The composition of the glycocalyx is cell specific and important in the formation of tissues. Similarly differentiated cells identify each other using this surface sugar matrix during ontogenesis to aggregate in tissue formation.
The glycocalyx is regenerated by synthesis of glycoproteins and glycolipids. The glycoproteins are synthesised in the rough endoplasmic reticulum and are then transported into the Golgi-apparatus to receive their sugar components and to get integarted into the membrane of Golgi-vesicles. Formation of glycolipids is also managed by the Golgi-apparatus. The Golgi-vesicles are then transported to the cell membrane to fuse with it.

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