Figure 1615

Photomicrograph of pyloric glands. This photomicrograph shows a section of the wall of the pylorus. The pyloric glands are relatively straight for most of their length but are slightly coiled near the mus-cularis mucosae. The lumen is relatively wide, and the secretory cells are similar in appearance to the surface mucous cells, suggesting a relatively viscous secretion. They are restricted to the mucosa and empty into the gastric pits. The boundary between the pits and glands is, however, hard to ascertain in routine H&E preparations. X120.

Excessive secretion of gastrin usually has its origin in a tumor of the gastrin-producing GEP endocrine cells located in the duodenum or in the pancreatic islet. This condition, known as the Zollinger-Ellison syndrome or gastrinomas, is characterized by excessive secretion of hydrochloric acid by continuously stimulated parietal cells. The excess acid cannot be adequately neutralized in the duodenum, thereby leading to gastric and duodenal ulcers. Gastric ulcers are present in 95% of patients with this syndrome and are 6 times more prevalent than the duodenal ulcers. Treatment of Zollinger-Ellison syndrome in the past involved blockage of the parietal cell membrane receptors that stimulate HCI production. Recently, proton pump inhibitors have become the treatment of choice in managing HCI hypersecretion. In addition, surgical excision of the tumor, when possible, removes the source of gastrin production and alleviates symptoms.

isted in a symbiotic relationship with the cells of the human stomach. The basis for this hypothesis is that the human proton pump (H+/I<+-ATPase) found in parietal cells bears a strong genetic similarity to proton pumps found in this bacterium. The bacterial DNA is thought to have been translocated and subsequently incorporated into the nucleus of the stem cells, probably with the help of a virus.

The chief and enteroendocrine cells are estimated to live for about 60 to 90 days before they are replaced by new cells migrating downward from the isthmus. The mucous neck cell, in contrast, has a much shorter lifespan, approximately 6 days.

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