In the enterocyte microvillus, the structural core is attached to the plasma membrane along its length by lateral arms made of myosin 1a and Ca2+ binding protein calmodulin.

Thousands of microvilli form a structure called the brush border that is found on the apical surface of some epithelial cells, such as the small intestines.

The nucleation of actin fibers occurs as a response to external stimuli, allowing a cell to alter its shape to suit a particular situation.

For example, the microvilli in the small and large intestines in mice are slightly different in length and amount of surface coat covering.

Because of this vital function, the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compounds that are more easily absorbed.

For example, enzymes that digest carbohydrates called glycosidases are present at high concentrations on the surface of enterocyte microvilli.

[6] Congenital lack of microvilli in the intestinal tract causes microvillus atrophy, a rare, usually fatal condition found in new-born babies.