Pancreas bicarbonate release

Most pancreatic secretion takes place during the intestinal phase. The intestinal hormone secretin stimulates release of a large volume of pancreatic juice with a high concentration of bicarbonate ion. Secretin is released in response to acidic chyme in the duodenum (maximal release at pH < 3.0). The intestinal hormone cholecystokinin is released in response to the presence of the products of protein and lipid digestion. Cholecystokinin then stimulates the release of digestive enzymes from the pancreas. 

As the acidic stomach contents pass into the small intestine, the low pH triggers secretion of the hormone secretin into the blood. Secretin stimulates the pancreas to secrete bicarbonate into the small intestine to neutralize the gastric HC1, abruptly increasing the pH to about 7. (All pancreatic secretions pass into the small intestine through the pancreatic duct.) The digestion of proteins now continues in the small intestine. Arrival of amino acids in the upper part of the intestine (duodenum) causes release into the blood of the hormone... 

When the stomach contents pass into the small intestine, the low pH causes the release of the hormone secretin from cells of the small intestine. Secretin causes the release of bicarbonate from the pancreas which neutralizes the hydrochloric acid and allows the hydrolytic enzymes trypsin, chymotrypsin, elastase and carboxypeptidase to function optimally at pH 7-8. 

Secretin is a 27-residue peptide amide hormone produced by S cells of the duodenum. The primary effect of secretin is stimulating the release of bicarbonate from liver, pancreas, and duodenal tissues to inhibit gastrin-induced gastric acid release. It also enhances the effects of cholecystokinin and promotes normal growth and maintenance of the pancreas. 

The cephalic phase of digestion stimulates only a fraction of the maximum possible levels of gastric and pancreatic secretions. This phase does not seem to produce a rise in the levels of gastrin and CCK. Cephalic stimulation of the pancreas, as mediated by the vagus nerve, provokes release of pancreatic enzymes into the small intestine. Cephalic stimulation of the parietal cells, as mediated by the vagus nerve, provokes release of gastric acid into the lumen of the stomach- In humans, the cephalic phase does not seem to result in release of bicarbonate into the lumen of the small intestine. 

Secretin enters the blo<>dstream and travels to the pancreas, where it stimulates the duct cells lo release bicarbonate and large volumes of fluid into the pancreatic duct The duct cells are located in the walls of the pancreatic duct. This duct leads from the acinar cells of the pancreas to the ampulla of Vater. The bicarbonate neutralizes the gastric acid entering the duodenum, providing an environment suitable for the functioning of enzymes and absorptive processes that re<]uire a neutral pH. 

MUSCLE RELAXANT and ANTISPASMODIC properties, secretin ]ban,inn,jan] (porcine secretin Hoe 69 Secretin-Ferring ) is a peptide hormone from duodenal mucosa which stimulates release of bicarbonate from the pancreas. It... 

Vasoactive inhibitory peptide (VIP) Small intestine, pancreas Vasodilator stimulates water and bicarbonate secretion, release of insulin and glucagon, and production of small intestinal juice... 

The major enzyme that digests dietary triacylglycerols is a lipase produced in the pancreas. Pancreatic lipase is secreted along with another protein, colipase, along with bicarbonate, which neutralizes the acid that enters the intestine with partially digested food from the stomach. Bicarbonate raises the pH of the contents of the intestinal lumen into a range (pH 6) that is optimal for the action of all of the digestive enzymes of the intestine. Bicarbonate secretion from the pancreas is stimulated by the hormone secretin, which is released from the intestine when acid enters the duodenum. 

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