As with other parts of the gastrointestinal tract, the wall of the stomach consists of four layers: a mucosa (Muc), a submucosa (SubM ), a muscularis externa (ME ), and a serosa. The mucosa is the innermost layer and reveals three distinctive regions (arrows). The most superficial region contains the gastric pits; the middle region contains the necks of the glands, which tend to stain with eosin; and the deepest part of the mucosa stains most heavily with hema 610 toxylin. The cell types of the deep (hematoxylin-staining) portion of the fundic mucosa are considered in bottom figure. The cells of all three regions and their staining characteristics are considered in Plate 57. The inner surface of the empty stomach is thrown into long folds referred to as rugae. One such cross-sectioned fold is shown here. It consists
Fundocardiac junction, stomach, human, H&E.
This figure and figure below show the fundocardiac junction between the cardiac and fundic regions of the stomach. This junction can be identified histologically on the basis of the structure of the mucosa. The gastric pits (P ), some of which are seen opening at the surface (arrows), are similar in both regions, but the glands are different. They are composed mostly of mucus-
Fundocardiac junction, stomach, human, H&E.
This figure provides a comparison between the cardiac and fundic glands at higher magnification. The cardiac glands (CG ) consist of mucous gland cells arranged as a simple columnar epithelium; the nucleus is in the most basal part of the cell and is somewhat flattened. The cytoplasm appears as a faint network of lightly stained material. The lumina (L) of the cardiac glands are relatively wide. On the other hand, the fundic glands (FG ) (left of the dashed line) are small, and a lumen is seen readily only in certain fortuitously sectioned glands. As a consequence, most of the glands of mucosa and submucosa (asterisks). The rugae are not permanent folds; they disappear when the stomach wall is stretched, as in the distended stomach. Also evident are mamillated areas (M ), which are slight elevations of the mucosa that resemble cobblestones. The mamillated areas consist only of mucosa without submucosa.
The submucosa and muscularis externa stain predominantly with eosin; the muscularis externa appears darker. The smooth muscle of the muscularis externa gives an appearance of being homogeneous and uniformly solid. In contrast, the submucosa, being connective tissue, may contain areas with adipocytes and contains numerous profiles of blood vessels (BV ). The serosa is so thin that it is not evident as a discrete layer at this low magnification.
secreting cells and occasional enteroendocrine cells. The boundary between cardiac glands (CG ) and fundic glands (FG ) is marked by the dashed line in each figure.
The full thickness of the gastric mucosa is shown here, as indicated by the presence of the muscularis mucosae (MM ) deep to the fundic glands. The muscularis mucosae under the cardiac glands is obscured by a large infiltration of lymphocytes forming a lymphatic nodule (LN ).
appear to be cords of cells. Because this is a deep region of the fundic mucosa, most of the cells are chief cells. The basal portion of the chief cell contains the nucleus and extensive ergastoplasm, thus, its basophilia. The apical cytoplasm, normally occupied by secretory granules that were lost during the preparation of the tissue, stains poorly. Interspersed among the chief cells are parietal cells (PC). These cells typically have a round nucleus that is surrounded by eosinophilic cytoplasm. Among the cells of the lamina propria are some with pale elongate nuclei. These are smooth muscle cells (SM ) that extend into the lamina propria from the muscularis mucosae.