Intestinal anatomy. Computer artwork showing the layers of the small intestine. The central space (lumen) is surrounded by the mucosa (beige,folded),which has numerous folds (villi). Surrounding this is the submucosa (beige) and then a layer of circular muscle (brown),followed by a layer of longitudinal muscle. The outer layer (beige,left) is the serous membrane (serosa). The arteries,which supply blood to the intestine,and veins that carry nutrients,absorbed during digestion,away from the intestine,can also be seen |