Stomach wall. Coloured scanning electron micrograph (SEM) of a section through a freeze- fractured fold in the stomach wall. The stomach is lined by the mucosa (purple), whose glands secrete gastric juices into the stomach lumen (cavity, top). At the base of the mucosa is the muscularis mucosae (light brown), a thin layer of smooth muscle which provides local movements and folding of the mucosa. The submucosa (beige) lies beneath the muscularis mucosae. It is a layer of loose connective tissue that contains blood vessels and nerves (not seen). Beneath the submucosa is the muscularis (dark red), a layer of smooth muscle. Magnification: x50 at 6x7cm size.