Pancreas

The pancreas is a soft, elongated gland with two distinct jobs in one organ. As an exocrine gland it makes powerful digestive enzymes; as an endocrine gland it produces hormones, including insulin, that regulate blood sugar. This dual nature makes it central to both digestion and metabolism.

Structure and Location

The pancreas lies retroperitoneally (behind the lining of the abdominal cavity), crossing the spine at about the L1 to L2 vertebrae in the upper abdomen, mostly behind the stomach. It has four regions: the head, cradled within the C-shaped curve of the duodenum; the neck; the body; and the tail, which reaches toward the spleen on the left. A central pancreatic duct runs its length and joins the bile duct to empty digestive juice into the duodenum. Blood is supplied by branches of the splenic, superior mesenteric, and common hepatic arteries.

Function

Most of the pancreas (about 80 percent) is exocrine tissue made of acinar cells that produce enzymes to digest carbohydrates, fats, and proteins. These enzymes travel through the pancreatic duct into the duodenum, along with bicarbonate that neutralizes stomach acid. Scattered among this tissue are the islets of Langerhans, the endocrine portion. Their cell types include beta cells (insulin, which lowers blood sugar), alpha cells (glucagon, which raises it), delta cells (somatostatin), and PP cells. These hormones are released directly into the bloodstream to keep glucose tightly controlled.

Clinical Relevance

Pancreatitis, inflammation of the gland most often caused by gallstones or alcohol, can be acute or chronic and is sometimes life-threatening when the organ's own enzymes begin digesting it. Pancreatic cancer (adenocarcinoma) is aggressive and frequently found late because early symptoms are vague. Loss or dysfunction of insulin-producing beta cells leads to diabetes mellitus. This content is educational and is not medical advice.