Intestinal lining. Coloured scanning electron micrograph (SEM) of a freeze-fractured intestinal surface. The fracture plane (lower frame) has cut down through the surface, revealing the deep folds called villi. The intestinal surface (orange) is where food is digested. It consists of a layer of surface (epithelial) cells (red), supported by connective tissue (orange). This connective tissue is seen in the fracture plane at the core of each fold (villus). The folds increase the area for the absorption of food. This tissue is from a part of the small intestine called the duodenum. Magnification unknown.