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Chapter 5 (page 21)
This zone comprises the greater part of the fornix and corpus, i.e. the proximal two-thirds
or more of the stomach. The glands are variously known as fundic glands, proper gastric
glands or principal gastric glands. As one of their most important properties is the
secretion of gastric acid, Grossman (l958) suggested the term "oxyntic" (Greek: acid-
forming) as an appropriate indicator of this glandular zone. The mucosa here is much
deeper than in the cardiac zone and contains a greater number of glands. The pits are
shallow and the glands extending from the bottoms of the pits are 2 to 3 times as long as
the pits are deep.
Each principal gastric gland is composed of 4 kinds of cells (Bevelander and Ramaley
- Chief, zymogenic or peptic cells. These are situated mostly in the deeper parts of
the glands. They exhibit secretory granules containing the precursors of pepsin.
- Parietal or oxyntic cells. These are most numerous in the necks of the glands.
They do not border directly on the lumen, but are crowded away from it by peptic cells.
Each cell is roughly triangular in shape, with the apex projecting towards the lumen
between the sides of two peptic cells that border it. These cells are intensely acidophilic,
contain the gastric proton pump mechanism, and produce the antecedent of hydrochloric
acid; they are also believed to elaborate intrinsic factor. The secretion of oxyntic cells
must pass between adjacent peptic cells that almost cover them, to reach the lumen.
- Neck mucous cells. These cells resemble the mucous cells of the cardiac and
pyloric zones. They are relatively few in number and are lodged between the parietal
cells in the necks of the glands; they are smaller than the surface mucous cells and their
mucigen granules are larger and less dense than those of the surface cells (Bevelander
and Ramaley l979). The secreted mucus is somewhat different from that secreted by the
surface mucous cells (Leeson l976).
- Neuroendocrine or APUD cells. These small, granulated cells occur singly in the
epithelium of the gastric mucosa (Bloom and Fawcett l975). They are scattered between
the peptic cells and are few in number. It is accepted that some of these cells are the site
of synthesis and storage of serotonin (5-hydroxytryptamine). Cells of the APUD line are
much more numerous in the pyloric mucosal zone and will be described separately
The glands of the oxyntic zone produce nearly all the enzymes and hydrochloric
acid secreted in the stomach; they also produce some of the mucus.
This zone comprises roughly the distal third of the stomach. Normally it extends further
along the lesser curvature than the greater, but its boundaries may vary (vide infra). The
pits are deeper in this zone than elsewhere in the stomach, extending into the mucous
membrane for half its thickness. The glands are also of a simple, branched tubular type,
but they branch more extensively and the tubules are coiled.
The glands contain the following types of cells:
- Mucous cells resembling the neck mucous cells of the oxyntic glands. These
large, mucus-secreting cells constitute the overwhelming number of cells in the pyloric
glands. They have a pale cytoplasm containing indistinct granules, the nucleus is often
flattened against the base of a cell, and short microvilli covered by a layer of mucus, are
present on the luminal surface.
- Parietal cells. A few isolated parietal cells may be present among the mucous
cells (Ito l967). Parietal cells also occur in the transitional region between the pyloric and
oxyntic zones (Bevelander and Ramaley l979).
- Neuroendocrine or APUD cells. These cells are much more numerous in the
pyloric than in the cardiac and oxyntic zones; when compared with the mucous cells they
are still relatively few in number. With light microscopy they have been called
enterochromaffin cells. With electron microscopy their cytoplasmic granules are clearly
visible after staining with chromium or silver salts. On the basis of their staining
reactions, the cells have been divided into two types, viz. argentaffin cells, in which the
granules reduce silver without pretreatment, and argyrophilic cells, in which a reducing
substance is required before the granules will react with silver (Bloom and Fawcett l975)
The glands of the pyloric mucosal zone do not produce enzymes, but secrete mucus; this
zone is also an important producer of endocrine, paracrine or neurocrine regulatory
peptides by virtue of the APUD cells contained in its glands (Chap 9).
The various mucosal zones of the stomach are not sharply delimited, and along the
borderlines the glands of one region mingle with those of the adjoining region;
intermediate glands may be present between the pyloric and body (i.e. oxyntic) mucosal
zones (Bloom and Fawcett l975).
The extent of the pyloric mucosal zone, and its boundaries on the oral and
aboral sides, may be determined by microscopic, macroscopic, surgical and other
methods. The microscopic identification of the pyloric mucosa in morbid
anatomical specimens is probably the most accurate method of determining the
boundaries of this zone. For instance, it has been stated in histology that
the pyloric mucosal zone usually comprises the distal 4-5cm of the stomach, and
that it extends farther along the lesser curvature than the greater (Bloom and
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