Embryology, Pancreas

Excerpt

The pancreas is a retroperitoneal gland that facilitates digestion and metabolism. The pancreatic head and uncinate process adjoin the duodenal curvature; its neck positioned posterior to the pylorus and anterior to the portal venous confluence. The pancreatic body lies posterior to the stomach; the tail enters the peritoneum near the splenic hilum. Unique for a foregut organ, the pancreas receives blood supply from branches of both the celiac trunk and superior mesenteric artery. Autonomic nerves forming the pancreatic plexus arise from the celiac ganglia, which coordinate sympathetic and parasympathetic synapses from the greater splanchnic and vagus nerves, respectively. Pancreatic tissue is largely composed of acini which secrete digestive proenzymes into a system of ducts that coalesce to form the main and accessory pancreatic ducts. Most exocrine secretions drain into the second part of the duodenum at the level of the major duodenal papilla where they aid in digestion through proteolysis and lipolysis.

There is dispersed endocrine tissue throughout the pancreatic parenchyma in functional units known as islets of Langerhans. These conglomerates secrete a host of hormones directly into the circulation, notably insulin, glucagon, and somatostatin. Derived from the foregut, the pancreas has endodermal origins and undergoes nuanced development in utero to become an organ with dual endocrine and exocrine functions. This embryologic review focuses on human pancreatic morphogenesis, physiologic maturation, and relevant congenital malformations in a clinical context.