Pancreas: The pancreas is a gland shaped somewhat like a fish. It is located behind the stomach with it head situated in the C-shaped curve of duodenum, its body extending horizontally across the posterior abdominal wall and its tail touching the spleen. The pancreas is both an exocrine and endocrine gland. The exocrine functions are in manufacturing and secreting pancreatic juice which empties into the duodenum via the main pancreatic duct (duct of Wirsung). This juice helps to break down all types of food. The endocrine functions involve certain cells (beta) of the islets of Langerhans scatted all over the gland, which secrete insulin, a hormone that plays a major role in carbohydrate metabolism. When these cells begin to lose their ability to produce insulin, the disease known as diabetes mellitus results. Other cells (alpha) of the pancreas secrete glucagon, another hormone involved in carbohydrate metabolism. The blood supply is derived from the splenic, superior mesenteric, and hepatic arteries. The veins accompany the arteries and drain into the portal vein by way of the splenic and superior mesenteric tributaries. Peripancreatic lymph nodes may be located superior, inferior, anterior or posterior to the organ, and the drainage will differ depending on whether it is from the head or body and tail of the pancreas. The lymph nodes for the pancreas are: splenic (pancreaticolineal [body and tail]), hepatic (infrapyloric/subpyloric [head], pancreaticoduodenal), superior mesenteric, celiac axis (head) and lateral aortic/retroperitoneal.