Minute structures densely covering and projecting from the surface membrane (called brush border) of intestinal epithelial cells that form villi for the purpose of absorbing nutrients and producing enzymes which finish digestion of carbohydrates including lactose, sucrose, and maltose and which prevent physical contact between foodstuffs and bacteria within the small intestine and all body cells.
Microvilli are so tiny they can only be seen by an electron microscope (100 nanometers thick and up to 2000 nanometers long).