Goblet cell. Coloured transmission electron micrograph (TEM) of a section through a goblet cell in the lining of the small intestine, part of the digestive tract. It is full of mucus. A goblet cell secretes the mucus to protect the lining of the intestine. The brush-like surface of the small intestine consists of microvilli which increase the surface area available for absorption of nutrients such as lipids, proteins and fat-soluble vitamins. The microvilli have a rapid turnover of 3-4 days. Magnification: x6800 when printed 10 centimetres wide.