Microvillus

Microvilli ( from Latin villus " villus " ) are thread-like cell processes which serve to increase the surface area of cells and thus improving the mass transfer. Microvilli are mainly in ( animal ) epithelial cells (eg, in the intestine, kidney, taste buds, uterus, ova ) are present.

Main Features

Microvilli are located on the basement membrane facing away ( apical ) side of the epithelial cell. This finger-shaped, brush-like protuberances have a reduced diffusion resistance for small molecules and are therefore suitable in their structure very well for the uptake and release of substances. They are transported along the stabilizing actin filaments which extend from the top of the microvilli to their approach. The transport is also supported by common rhythmic contractions and pumping operations.

Structure

The finger-like microvilli are approximately 0.1 microns thick and depending on the cell type up to 2 microns long. Each microvillus contains a core bundle of actin filaments. Will be interpreted as held together by proteins fimbrin and fascin in shape. To the lateral surface, the actin bundles is connected by myosin -I and the cytoskeleton in the basal through spectrin. Each microvillus bears at the apical end of an amorphous cap region.

The microvilli are coated with a layer of proteins, glycoproteins and sugar residues which is called glycocalyx. Antigenic properties are determined by them. Also plays a role in the glycocalyx cell recognition and adhesion mechanisms.