Figure 1.

Typical anatomy and histology of a mammalian stomach. There are a number of variations in mammalian gastric anatomy. For example, mice have a forestomach with keratinized squamous epithelium, whereas humans have a pronounced cardiac region with simpler mucous glands that mark the transition region between the esophagus and corpus. However, the most prominent regions in most mammals are a proximal corpus, encompassing most of the stomach volume, and a distal antrum or pylorus. The corpus epithelium is organized into repeating gastric units that are invaginations from the surface and contain multiple cell lineages in 4 distinct zones. In the diagram, acid-secreting parietal cells are blue, digestive enzyme secreting zymogenic (chief) cells are red, mucous neck cells are green, and the mucus-secreting pit cells nearest the surface are purple. In the antrum, the gastric units are simpler, with few parietal or zymogenic cells. Antral units contain 2 distinct types of mucous cells: those lining the surface (purple) are similar to the surface cells of the corpus, and those nearer to the base have properties intermediate between zymogenic cells and mucous neck cells of the corpus (red-yellow). The interfaces between esophagus and corpus and between corpus and antrum are not abrupt but marked by transitional mucosae. Endocrine cells (not depicted) are also present throughout the corpus and antrum epithelium.