Small intestine. Light micrograph of a section through the jejunum of the small intestine. The large projections from the intestinal wall are plicae circulares, covered in finger-like villi (pink). These increase the surface area for the digestion and absorption of food. The layer beneath the villi is the muscularis mucosae, which is supported by the submucosa (blue and white). The submucosa contains blood vessels. The jejunum is the middle part of the small intestine, linking the duodenum (by the stomach) to the ileum (by the large intestine). Magnification: x15 at 6x7cm size.