Find the luminal surface, which is in striking contrast with the surface of small intestine. Unlike the small intestine, the colon mucosa consists of only glands. Note the numerous cross-sectional profiles of the glands. No villi are present. The lining epithelium contains mainly goblet cells, a few enterocytes, and migrating lymphocytes.
Paneth cells are noticeably absent from the crypts.
Review and compare the epithelial lining of the surface with that in the crypts. The submucosa contains numerous large blood vessels. The muscularis externa has two layers of smooth muscle. Find the circular and longitudinal layers of smooth muscle and elements of Auerbach's plexus. Identify the teniae coli, an enlargement of the outer longitudinal layer of muscularis externa.