Villus of small intestine. Coloured scanning electron micrograph (SEM) showing a healthy villus of the small intestine. The villus' epithelium (lining) is made up of mucus-producing goblet cells (pink) and polygonal absorptive cells (purple). Villi are finger-like projections from the intestinal wall which greatly increase the absorptive surface of this part of the digestive system. Mucus secretions aid the movement of food through the intestines. The small intestine is around 6 metres long, providing a large surface area for effective food absorption. This is the jejunum, the central part of the small intestine. Magnification unknown.