Colon surface. Coloured Scanning Electron Micro- graph (SEM) of the glandular surface of the wall (mucosa) of the human colon. The colon is part of the large intestine. Its inner epithelial surface, as seen here, is folded. Two types of epithelial cells make up this surface: enterocytes (brown) covered in tiny bumps (microvilli) that enhance water absorption and give the surface a furry appearance; goblet cells (grey) found in small rounded depressions, and which secrete mucus. The glandular colon wall is lubricated with mucus, and it functions to produce faeces by absorbing water and vitamins from the food residue. Magnification: x400 at 6x6cm size.