The pancreas is a relatively small organ, which weighs around 100 grams and is about 15cm in length. It is the digestive system's main enzyme producing organ, and can be likened to a factory. Most pancreatic cells produce millions of enzymes daily. The pancreas is subdivided into small lobes, with ducts entering into a main duct. Along with the bile duct, the pancreatic duct enters the small intestine to deliver fluid through a small hole in the wall of the second part of the duodenum known as the papilla. This fluid is known as pancreatic juice, of which approximately 1.5 litres is produced each day. It is a rich mixture, containing enzymes capable of digesting all food types - protein, fat and carbohydrate. These enzymes are activated in the small intestine as needed. Pancreatic juice is highly alkaline, to help neutralise the acidity of the food which has just left the stomach.

A variety of hormones are also produced in the pancreas. These are made by cell clusters - Islets of Langerhans - interspersed throughout the tissue. Two major hormones are insulin and glucagon, which regulate carbohydrate metabolism. Other hormones control the release of pancreatic juice.