False-colour scanning electron micrograph (SEM) of intestinal villi in the duodenum. These villi are long ridge-like folds in the wall of the duodenum, which project into the lumen (above). Villi greatly increase the absorptive and secre- tory surface of the duodenum. Digestive & stomach- acid neutralising enzymes are secreted by the duodenum; food is further digested here; this food is then absorbed into the blood through capillaries found in each villus. To aid food absorption, villi are most widely distributed in the duodenum than elsewhere in the intestine. Magnification: x55 at 6x7cm size. Magnification: x85 at 4x5 inch size.