Intestinal microvilli. Coloured transmission electron micrograph (TEM) of a section through microvilli from the small intestine. These tiny structures (green) form a dense brush-like covering on the absorptive surfaces of the cells lining the small intestine. These cells (light brown) absorb nutrients from digested food through these microvilli. There are billions of microvilli in a small intestine. Magnification: x20,000 when printed at 10 centimetres wide.