MICROANATOMY

Detailed explanation-1: -S cells in the small intestine emit secretin. Gastric acid stimulates secretin release, allowing movement into the duodenal lumen. Secretin causes an increase in pancreatic and biliary bicarbonate secretion and a decrease in gastric H+ secretion. Secretin stimulates the secretion of bicarbonate-rich pancreatic fluid.

Detailed explanation-2: -The tissues of the pancreas (acinar cells) produce a clear digestive fluid made up of bicarbonate, and enzymes. Bicarbonate is alkaline, and helps digestion by neutralizing the stomach acid containing the food as it passes into the duodenum.

Detailed explanation-3: -Secretin stimulates the secretion of a bicarbonate-rich pancreatic fluid (45). Secretin enters the blood stream or intestinal lumen and stimulates bicarbonate secretion (by interacting with pancreatic ductal cells), which neutralizes the pH of the gastric chyme upon entering the small intestine (83, 84).