Mills Ch22 Stomach

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SECTION VII : AlimentaryTract

FIGURE 22.7  Gastric surface epithelium showing cytoplasmic mucus present in multiple small vacuoles.

FIGURE 22.5  Gastric surface epitheliumwith each cell having amucous globule in the superficial cytoplasm. Intraepithelial lymphocytes are present. These are surrounded by a clear halo (formalin fixation artifact).

strict anatomic esophagogastric junction. This is also the point where the gastric mucosal folds begin. Columnar epi- thelium that is present in flat mucosa proximal to the muco- sal folds is considered to be within the anatomic esophagus and metaplastic in origin. In some individuals, the mucosal junction is located 0.5 to 2.5 cm proximal to the anatomic junction and may be serrated, rather than being a regular circumferential line (Z line). Surface Epithelium Histologically, the gastric mucosa is covered by tall, colum- nar, mucus-secreting cells with intervening foveolae that are lined by a similar epithelium (Fig. 22.5). The surface and foveolar lining cells are similar throughout all the mucosal zones of the stomach. The gastric glands empty into the base of the foveolae. Separating the foveolae and the glands is the lamina propria. In the cardiac and pyloric mucosal zones, the foveolae are wider than in other areas, sometimes giving the mucosa a slightly villous appearance (Fig. 22.6).

The cells of the surface epithelium and foveolae are tall and columnar with basally situated nuclei and superficial cytoplasm that is almost entirely filled with mucus (Fig. 22.7). The nuclei have an even distribution of chromatin, with single inconspicuous nucleoli. On hematoxylin and eosin (H&E)-stained sections, the appearance of the mucus varies, depending on the exact type of stain used. For example, with alcoholic eosin, the mucus appears as a single vacuole that is clear or lightly eosinophilic. With aqueous eosin, the mucus is more heavily eosinophilic and is seen to be present in numer- ous, small, closely aggregated vacuoles. Histochemically, the foveolar mucus is all neutral, periodic acid–Schiff (PAS) positive, but Alcian blue negative at pH 2.5 and lower (9). Cardiac and Pyloric Mucosa In the cardiac and pyloric zones, the foveolae occupy approxi- mately one-half of the mucosal thickness (Fig. 22.6). Both the cardiac and pyloric glands are mucus secreting and are loosely packed with abundant intervening lamina propria (Fig. 22.8).

FIGURE 22.6  Gastric pyloric mucosa. Note that the glands are loosely packed and occupy about half the mucosal thickness. The surface epithelium appears slightly villous.

FIGURE 22.8  Pyloric glands containing cells with a bubbly, foamy appearance.