Pancreas: a large, slender grape-shaped gland, lying behind the stomach and between the spleen and duodenum; Its right end (pancreatic head) is large and downward, its left end (pancreatic tail) is horizontal, and its tail is against the spleen. Exocrine or pancreatic juice of pancreas is imported into duodenum through pancreatic duct, which contains various digestive enzymes. There are also scattered island-like cell clusters in the pancreas, called islets or Langerhans islands. β -cells of islet secrete insulin, promote hypoglycemia and promote the synthesis of hepatic glycogen. Pancreatic islet α -cells secrete glucagon, which can promote the decomposition of hepatic glycogen and increase blood sugar. Insulin and glucagon feed back each other to control blood sugar in a small range. If insulin is absolutely or relatively insufficient for any reason, it will lead to diabetes. On the lower left diaphragm of the left quarter rib stomach.