The pancreas, nestled between the stomach, small intestine and spleen in the abdomen, secretes digestive enzymes through the pancreatic duct into the small intestine. Most of the pancreatic tissue is devoted to the production of these digestive enzymes.

The organ is called the pancreas, but medical researchers refer to the endocrine pancreas and the exocrine pancreas as if they were different. The organ affected in diabetes is the endocrine pancreas. The shape of this organ is unusual; it is an archipelago, with clusters of cells distributed through the pancreas. The islets are concentrated in the tail of the pancreas. The larger islets look like small grains of sand, and the smaller islets look like mist.