Key

BV, blood vessels CG, cardiac glands FG, fundic glands L, lumen

LN, lymphatic nodule M, mamillated areas

ME, muscularis externa MM, muscularis mucosae Muc, mucosa

P: Fig. 2, gastric pits; Fig. 3, parietal cells SM, smooth muscle cells SubM, submucosa arrows: Fig. 1, three differently stained regions of fundic mucosa; Fig. 2, opening of gastric pits asterisks, submucosa in ruga dashed line, boundary between cardiac and fundic glands

Ruga

Ruga

The epithelial lining of the alimentary canal is a regularly renewing epithelium; each portion has a characteristic turnover time and stem cell location. In the stomach, stem cells are located in the mucous neck. Cells that migrate upward to form the mucous cells of the gastric pit and surface have a turnover time of 3 to 5 days; cells that migrate downward to form the parietal cells, chief cells, and enteroendocrine cells of the glands have a turnover time of about 1 year.

Figure 1, stomach, monkey, H&E x320.

This figure shows an area of the fundic mucosa that includes the bottom of the gastric pits and the neck and deeper part of the fundic glands. It includes the areas marked by the arrows in Figure 1 of Plate 52. The surface mucous cells (MSC) of the gastric pits are readily identified because the mucous cup in the apical pole of each cell has an empty, washed-out appearance. Just below the gastric pits are the necks (TV) of the fundic glands, in which one can identify mucous neck cells (MNC) and parietal cells (PC). The mucous neck cells produce a mucous secretion that differs from that produced by the surface mucous cells. As seen here, the mucous neck cells display a cytoplasm that is lightly stained; there are no cytoplasmic areas that stain intensely, nor is there a characteristic local absence of staining as in the mucous cup of the surface mucous cells. The mucous neck cells are also the stem cells that divide to give rise to the surface mucous cells and the gland cells.

Parietal cells are distinctive primarily because of the pronounced eosinophilic staining of their cytoplasm. Their nucleus is round, like that of the chief cell, but tends to be located closer to the basal lamina of the epithelium than to the lumen of the gland because of the pear-like shape of the parietal cell.

This figure also reveals the significant characteristics of chief cells (CC), namely, the round nucleus in a basal location; the ergastoplasm, deeply stained with hematoxylin (particularly evident in some of the chief cells where the nucleus has not been included in the plane of the section); and the apical, slightly eosinophilic cytoplasm (normally occupied by the secretory granules).

Figure 2, stomach, monkey, H&E x320.

This figure shows the bottom of the stomach mucosa, the submucosa (SubM), and part of the muscularis externa (ME). The muscularis mucosae (MM) is the deepest part of the mucosa. It consists of smooth muscle cells arranged in at least two layers. As seen in the photomicrograph, the smooth muscle cells immediately adjacent to the submucosa have been sectioned longitudinally and display elongate nuclear profiles. Just above this layer, the smooth muscle cells have been cut in cross section and display rounded nuclear profiles.

The submucosa consists of connective tissue of moderate density. Present in the submucosa are adipocytes (A), blood vessels (BV), and a group of ganglion cells (GC). These particular cells belong to the submucosal plexus (Meissner's plexus [MP]). The inset shows some of the ganglion cells (GC) at higher magnification. These are the large cell bodies of the enteric neurons. Each cell body is surrounded by satellite cells intimately apposed to the neuron cell body. The arrowheads point to the nuclei of the satellite cells.

Figure 3, stomach, silver stain x160.

Enteroendocrine cells constitute a class of cells that can be displayed with special histochemical or silver-staining methods but that are not readily evident in H&E sections. The distribution of cells demonstrable with special silver-staining procedures is shown here (arrows). Because of the staining procedure, these cells are properly designated as argentaffin cells. The surface mucous cells (MSC) in the section mark the bottom of the gastric pits and establish the fact that the necks of the fundic glands are represented in the section. The argentaffin cells appear black in this specimen. The relatively low magnification permits the viewer to assess the frequency of distribution of these cells.

Figure 4, stomach, silver stain x640.

At higher magnification, the argentaffin cells (arrows) are almost totally blackened by the silver staining, although a faint nucleus can be seen in some cells. The silver stains the secretory product lost during the preparation of routine sections, and accordingly, in H&E-stained paraffin sections the argentaffin cell appears as a clear cell. The special silver staining in this figure and in Figure 3 shows that many of the argentaffin cells tend to be near the basal lamina and away from the lumen of the gland.

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