The pancreas secretes the base bicarbonate (HCO3-) into the duodenum to neutralize the acidic chyme entering from the stomach.
The key pancreatic and digestive functions are:
• The pancreas produces a variety of enzymes through the pancreatic duct, including proteases like trypsinogen and chymotrypsinogen, lipases like pancreatic lipase, and nucleases like deoxyribonuclease. These enzymes help digest proteins, lipids and nucleic acids in the small intestine.
• Along with the enzymes, the pancreas secretes high concentrations of bicarbonate ions (HCO3-) into the pancreatic duct.
• The bicarbonate ions are bases that help neutralize the acidic chyme entering the small intestine from the stomach. The average pH of gastric chyme from the stomach is around 2-3, while the small intestine has a pH closer to 7-8 for optimal enzyme function.
• By secreting bicarbonate into the duodenum, the pancreas raises the luminal pH into a more alkaline range and neutralizes the gastric acids. This allows the pancreatic enzymes to work properly on the partially digested food.
• The bicarbonate generated by the pancreas also forms a "bicarbonate umbrella" that helps protect the duodenal mucosa from damage by the acidic gastric contents.
So in summary, the pancreas secretes high concentrations of bicarbonate ions that neutralize the acidic chyme entering the small intestine from the stomach, helping create an optimal environment for pancreatic enzyme function and digestion.