Stimulation of Secretin Production in Intestinal Wall Cells

Secretin is a hormone produced by the S cells of the duodenal mucosa in response to acid in the chyme entering the duodenum. This hormone is responsible for regulating the pH of the chyme that enters the small intestine. The cells in the wall of the intestine are stimulated to produce secretin by the following factors:

Acid in Chyme

The presence of hydrochloric acid in the chyme entering the duodenum stimulates the S cells in the duodenal mucosa to produce secretin. The acid triggers the release of the hormone, which then travels through the bloodstream to its target organs.

Effects of Secretin

Secretin has several effects on the digestive system, including the following:

- Increases the secretion of bicarbonate-rich pancreatic juice: Secretin stimulates the pancreas to produce a bicarbonate-rich pancreatic juice that neutralizes the acidic chyme entering the duodenum.
- Inhibits gastric acid secretion: Secretin inhibits the secretion of gastric acid by the parietal cells of the stomach, thereby reducing the acidity of the chyme entering the duodenum.
- Increases bile secretion: Secretin stimulates the liver to produce and secrete bile into the duodenum, which emulsifies fats and aids in their digestion.

Conclusion

In summary, the cells in the wall of the intestine are stimulated to produce secretin by acid in the chyme entering the duodenum. Secretin plays a crucial role in regulating the pH of the chyme and enhancing the digestion and absorption of nutrients in the small intestine.

When hydrochloric acid passes from the stomach into the duodenum, secretin is released into the bloodstream and stimulates the acinar cells of the pancreas to secrete water and bicarbonate into the pancreatic ducts that drain into the duodenum. By this mechanism, hydrochloric acid secreted by the stomach, which can be damaging to the intestinal lining, is promptly diluted and neutralized. Secretin also inhibits the secretion of gastrin, which triggers the initial release of hydrochloric acid into the stomach, and delays gastric emptying