Secretin is a hormone produced by the duodenum, which is the first part of the small intestine. It is released in response to acidic chyme entering the duodenum from the stomach. Secretin plays a crucial role in regulating the pH of the intestinal environment by stimulating the pancreas to release bicarbonate, which neutralizes stomach acid. In addition to its effects on the pancreas, secretin also influences the liver to produce bile and helps regulate digestive processes. This hormone is essential for proper digestion and absorption of nutrients, ensuring that the intestines function effectively after food passes through the stomach.