Firstly, we'll revisit some basic anatomy regarding the position of and the anatomical relations to the pancreas. The pancreas is found in the transpyloric plane in the epigastric and left hypochondrium regions. The head of the pancreas can be found within the C-shaped duodenum, which itself can be split into four separate parts. D1, also known as the superior or bulbar duodenum. D2 or the descending duodenum, D3 or the inferior horizontal duodenum, and D4 also known as the ascending duodenum. The distal portion or the tail of the pancreas is in close contact with the spleen. The pancreas is found posterior to the stomach from which it is separated by the lesser sac. Briefly revisiting embryology, the lesser sac, which is also known as the omental bursa, is a cavity in the abdomen that is formed during the rotation of the stomach and growth of the liver during foetal development. The abdominal cavity is originally split into a right and left sac, separated by the developing abdominal organs encased in peritoneum. The organs grow and rotate, with the liver moving to occupy most of where the right sac was. The pancreas develops behind the peritoneum, behind both the right sac and the stomach. In the fully formed foetus, the right sac becomes the lesser sac, which is smaller and seen here in dark blue, and the left sac becomes the greater sac, which is larger and seen here in light blue. The two sacs are connected via a small opening called the foramen of Winslow or the epiploic foramen. It is found on the free border of the hepatoduodenal ligament which encases the porta hepatis. Again in this image the pancreas can be seen behind the peritoneum or retroperitoneal separated from the stomach by the lesser sac. The common bile duct ascends within the head of the pancreas before combining with the major pancreatic duct to form the ampulla rivata, through which bile and pancreatic juices can pass into the duodenum. The pancreas also has many segments or parts. The pancreas can be further split into the head, which lies within the C-shaped curve created by the duodenum, the uncinate process, found inferior to the head but wrapping posteriorly to the superior mesenteric vessels, The neck, which directly overlies the superior mesenteric vessels, with the vessels forming a groove on its posterior aspect. The body, which lies behind the stomach and to the left of the superior mesenteric vessels. And the tail, which is found laterally and lies within close proximity to the hilum of the spleen. It is contained, along with the splenic vessels, within the splenorenal ligament which principally connects the spleen to the left kidney. The tail is the only part of the pancreas that is intraperitoneal, with the rest, including the head, uncinate process, neck and body, all being retroperitoneal. The majority of the blood supply to the pancreas arises from the coeliac trunk. The neck, body and tail of the pancreas are supplied by pancreatic branches of the splenic artery, which is a direct branch of the coeliac trunk. The head and the uncinate process are supplied by the superior and inferior pancreaticoduridinal arteries. The superior pancreaticoduridinal artery is a branch of the gastroduodenal artery, which is a branch of the common hepatic artery, also another main branch of the celiac trunk. So it goes celiac trunk, which then gives rise to the common hepatic artery, which then gives rise to the gastroduodenal artery, which finally gives rise to the superior pancreaticoduridinal artery. The inferior pancreaticoduridinal artery is a branch of the superior mesenteric artery, which arises further down the abdominal aorta. For the sake of completion, the third branch of the celiac trunk, the left gastric artery, is also shown here. Now to look at some physiology. Physiologically, the pancreas can be split into both an exocrine pancreas and an endocrine pancreas. The exocrine or ductal pancreas comprises acinar cells which produce pancreatic enzymes needed for digestion, examples of which are trypsinogen, amylase and lipase. The enzymes are secreted in an inactive form which then travel through the ductal system and enter the duodenum where they are activated. The endocrine pancreas is chiefly comprised of islet cells. These actually only make up 1-2% of all pancreatic tissue. These cells produce and secrete the hormones insulin and glucagon. The cells are organised into groups each known as an islet of Langerhans. with each group predominantly composed of both beta cells and alpha cells. The beta cells within the islet produce insulin, which is released to decrease glucose levels when they are high. The alpha cells in the islet release glucagon, which is released when glucose levels are low in order to increase the levels in the blood. The islets also contain a small number of delta cells, which can secrete somatostatin.