Microvilli are microscopic cellular membrane protrusions that increase the surface area of cells, and are involved in a wide variety of functions, including absorption, secretion

Secretion

Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, the substance may have a certain function, rather than being a waste product...

, cellular adhesion, and mechanotransduction

Mechanotransduction

Mechanotransduction refers to the many mechanisms by which cells convert mechanical stimulus into chemical activity.- Tendon :The process of is explained for the lay-reader at http://bjsm.bmj.com/content/43/4/247.full- Ear :...

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Thousands of microvilli form a structure called the brush border

Brush border

A brush border is the name for the microvilli-covered surface of simple cuboidal epithelium and simple columnar epithelium cells found in certain locations of the body. Microvilli are approximately 100 nanometers in diameter and their length varies from approximately 100 to 2,000 nanometers in...

 that is found on the apical surface of some epithelial cells, such as the small intestinal
Microvilli are observed on the plasma surface of eggs, aiding in the anchoring of sperm cells that have penetrated the extracellular coat of egg cells.