The stomach contains various gastric glands that secrete different substances essential for digestion. Here's a breakdown of the main types and their products:
1. Mucous Neck Cells:
* Product: Mucus (alkaline)
* Function: Protects the stomach lining from the acidic environment and digestive enzymes.
2. Parietal Cells:
* Products:
* Hydrochloric Acid (HCl): Activates pepsinogen, kills bacteria, and denatures proteins.
* Intrinsic Factor: Essential for the absorption of vitamin B12 in the small intestine.
* Function: Creates the acidic environment necessary for digestion and protects against infections.
3. Chief Cells:
* Product: Pepsinogen (inactive enzyme precursor)
* Function: Pepsinogen is activated by HCl into pepsin, the primary enzyme responsible for protein digestion.
4. Enteroendocrine Cells:
* Products: Various hormones, including:
* Gastrin: Stimulates parietal cells to produce HCl and chief cells to release pepsinogen.
* Somatostatin: Inhibits gastrin release.
* Histamine: Stimulates HCl secretion from parietal cells.
* Function: Regulate the overall activity of the gastric glands and digestion.
5. G Cells:
* Product: Gastrin
* Function: Stimulates the production of HCl and pepsinogen, promoting gastric motility and emptying.
6. D Cells:
* Product: Somatostatin
* Function: Inhibits gastrin release, reducing HCl production and gastric motility.
7. ECL Cells (Enterochromaffin-like Cells):
* Product: Histamine
* Function: Stimulates HCl secretion from parietal cells.
Note: Not all gastric glands contain all types of cells. The specific composition varies depending on the location within the stomach.
