1.g cells?

McGuigan( 1986) proved the existence of gastrin in the pyloric gland of pig stomach by immunohistochemical technique, and named it gastrin cell (G cell). Gastrin cells are distributed in human gastric pyloric gland epithelium 1/3 or slightly deeper. Under the light microscope, it was silvery after Grimy's silver staining, and it was considered to be lead hematoxylin. Medium orientation. Particle diameters vary from 200 to 350 nm, 200 to 400 nm, 300 mm, 80 to 300 nm, 133 to 460 nm, 15 1 400 nm or 188. There is a thin electron transparent band between the G cell and the capsule. G cells are open cells, the top of which extends into the glandular cavity, with microvilli protruding from the top, which may respond to the stimulation from the cavity. G cells can be secreted by mechanical or chemical stimulation, and can also be regulated by nerve and blood components. So far, there is no specific routine histological or histochemical reaction to prove G cells. Immunohistochemistry is the only method to selectively prove G cells. But it's the only way.

G cells release gastrin through exocytosis. First, the envelope of secretory granules is fused with the cell membrane, and then an opening appears in the combined membrane, through which the contents of granules are released to the extracellular space. It is proved that G cells can release their products not only from the base or side of cells, but also from the top of cells to the glandular cavity (1977). It is said that gastrin exists not only in blood and tissues, but also in human gastric juice. It can diffuse to adjacent target cells through extracellular space in a paracrine way and play a role; Secretion can also be released into the stomach cavity through exocrine (or intraluminal secretion), but what role it will play in the stomach cavity is not clear.

The most basic function of gastrin is to stimulate parietal cells to secrete hydrochloric acid; Stimulate the secretion of enzymes in the stomach and pancreas; Stimulate stomach, pancreas, liver and duodenal gland to secrete water and electrolyte; Stimulate the growth of stomach (bottom, body), small intestine and colon mucosa; Stimulate the blood flow of stomach, small intestine and pancreas; Stimulate the contraction of esophageal sphincter, stomach, small intestine and gallbladder; Inhibit the contraction of Oddi sphincter of pylorus; Inhibit the absorption of water and electrolyte by small intestine.

2.EC cells?

It is the abbreviation of intestinal chromaffin cells, accounting for the largest number of basal granular cells. In the stomach, it is distributed in the mucosa of gastric fundus gland, pyloric gland and cardiac gland. Under the light microscope, the particles are chromaffin, argyrophilic and argyrophilic. Falck-Hillarp method can emit strong yellow fluorescence. Immunohistochemical method proved that it contained 5- hydroxytryptamine (5-HT). Under the electron microscope, the diameters of secretory particles can be 200-300 nm, 250-300 nm, 300 nm and 249 nm. Particles can be round, oval, long, pear-shaped, triangular, kidney-shaped, U-shaped, ordinary double-sided concave and so on. And are all coated. A small number of particles containing 5-HT are mostly round and have weak tropism. When HT is rich in innuendo, the particles are polymorphic and have strong Austrian love. There are Aoo corpuscles or granules in the granules.

Gastrointestinal tract is the largest repository of serotonin. About 90% of 5-HT exists in gastrointestinal EC cells, and a small amount exists in myenteric plexus, longitudinal muscle and nerve. Many physiological and pathological processes of human beings involve 5-HT, which mainly acts on the smooth muscle of blood vessels and gastrointestinal tract. The effect on blood vessels varies with the dose and the location of blood vessels. Vascular contraction is the main function. Mainly dilate skeletal muscle blood vessels. Stimulating the smooth muscle of gastrointestinal tract can significantly strengthen the peristalsis of small intestine. As a visceral neurotransmitter, 5-HT affects the neuroregulation of gastrointestinal smooth muscle function, and can also directly act on mesenteric vascular smooth muscle or affect gastrointestinal blood flow through visceral nerves. It has been reported that 5-HT can stimulate the production and release of mucus in stomach and colon, and 5-HT can inhibit the secretion of gastric acid and the release of somatostatin.

3.ECL cells?

That is, intestinal chromaffin-like cells are mainly distributed in gastric fundus glands, mostly at the bottom or body of glands, and rarely in the neck. Cells are closed, the top of which does not reach the surface of the glandular cavity, and are often buried between parietal cells and main cells, and the basal surface is close to the basement membrane. ECL cells are small in size, irregular in shape and strongly silvery. Under the electron microscope, vacuolar particles with a diameter of about 250nm or 450nm can be seen, among which there is a high summer nucleus. The gap between the latter and the capsule is very small. Recently, histamine was proved to exist in the secretory granules of ECL cells by immunohistochemical method. It is generally believed that the mast cells of ECL cells release secretions into the intercellular space in a paracrine way, and diffuse to nearby target cells with cell fluid to play a local mediation role, because there are many histamine acids in gastric mucosa, which can destroy histamine. Under physiological conditions, histamine is destroyed by histamine enzyme after completing local functions.

In the digestive system, histamine can stimulate the secretion of parietal cells and main cells, make smooth muscle spasmodic contraction, relax blood vessels (smooth muscle) and increase capillary permeability. It is worth mentioning that histamine, gastrin and acetylcholine promote each other in stimulating parietal cells to secrete gastric acid, among which histamine plays a key role. If histamine H2 receptor antagonist is used, gastric acid secretion can be significantly reduced, which seems to indicate that the antagonist is being treated.

4.d cells?

In the stomach, it can be found in cardia gland, fundus gland and pyloric gland, so it is named because its shape is very similar to that of D cells in islets. Under the light microscope, the particles showed negative or weak reaction by Grimelius method and Sevier-Munger method, and positive by Davenport method and Hellman-Hellerstrom method. Under the electron microscope, the particles are large and round. The diameter can be between 142 ~ 427 nm, 200 ~ 400 nm, 260 ~ 370 nm, 300 ~ 400 nm and 350 nm. Uniform particle content, medium electron density, weak Austrian affinity, and the coating is usually close to the center. The size, appearance and electron density of particles can be obviously different among different genera, and there are great differences in rats.

In the fundus of stomach, D cells have typical endocrine cell morphology, which is closed and not in direct contact with the glandular cavity. D cells in gastric antrum are open, and the apical process can reach the glandular cavity. It is said that these cells can be directly affected by intraluminal factors (including pH). One or several long protrusions parallel to the basement membrane often protrude from the basal part of D cells, and contact with other endocrine and exocrine cells at a certain distance. The process of D cells in gastric antrum can terminate in G cells. On the other hand, the protrusion of D cells in the stomach body or fundus can terminate in parietal cells and other epithelial cells. Based on this morphological feature, it is speculated that after D cells release secretions, they only affect the target cells locally through paracrine pathway. However, it is also reported that it also has the function of endocrine hormone.

Although the morphology of D cells has long been known, it was not until 1975 that somatostatin was confirmed by immunohistochemical method. So far, it has been proved that somatostatin can inhibit the release of many regulatory peptides, such as growth hormone, thyrotropin, prolactin, gastrin, trypsin, glucagon, insulin, pancreatic polypeptide, cholecystokinin, motilin, gastrin and glucagon.

5.D 1 cell?

During the period of 1967 ~ 1972, many researchers observed a cell with small round particles (about 150nm in diameter), with a thin and clear gap between the dense core and the gastric sac. Because it is similar to pancreatic D cells, the silver reaction (positive by Grimelius method) is different from that of D cells. The particle size is 7 1 ~ 178 nm, 150nm, 160nm, 140 ~ 190 nm. 180 ~ 200 nm. Capella and Pollack (et al. 1976) originally called this cell H. At present, the early statement that D 1 cells contain vasoactive intestinal peptide-like substances (VIP-like substances) has been denied, and VIP has been proved to exist only in the nervous system. Kobayashi et al. recently pointed out that the D 1 cell mentioned in the paper published by Solcid et al. is not a single cell, and may include so-called M cells (M0 cells). The particle size of M cells is 186nm or 150 ~ 250nm, which is equivalent to I cells found in human duodenum and jejunum. The diameter of secretory granules of the latter is 150. What kind of peptide hormones it secretes is unknown.

In the stomach, in addition to the above endocrine cells, there are also P cells and X cells. P cells only exist in the antrum of normal people. In the cases of chronic atrophic gastritis and gastric carcinoid, P cells often appear in large numbers. The secretory granules of P cells are very small, with a diameter of about 120nm, round and dim. It is said that bombesin secreted by P cells can obviously stimulate gastrin secretion and gallbladder contraction. Therefore, it is speculated that the ulcer may be related to the increase of P cells and bombesin. X cells are distributed in gastric mucosa, and the number is very small. These particles are medium in size (50 nanometers), round and have high electron density, and are tightly surrounded by a capsule. Their functions are still unclear.

In recent years, gastrin, gastrin and vagal gastrin have also been discovered by biochemical and immunohistochemical methods. There is no consistent understanding of their biochemical properties, physiological functions and related endocrine cells. At present, only endocrine cells related to various candidate hormones are called "some substance-like immune response cells".