Development of human pancreas

Abstract

Pancreas is an exocrine and endocrine organ. Exocrine portion secretes digestive fluid. Endocrine portion secreting insulin and glucagon etc. Pancreas developed from dorsal and ventral pancreatic buds, which arise from either side of distal foregut. When duodenum rotates to right, ventral pancreatic bud(VPB) rotates posterior along with common bile duct(CBD) and finally lies below and behind the dorsal pancreatic bud(DPB). In humans, DPB forms major part and VPB forms inferior part of head and uncinate process of pancreas. Main duct (Duct of Wirsung) is derived from whole of ventral pancreatic duct(VPD) and distal part of dorsal pancreatic duct(DPD). Main duct joins with CBD and it perforated posteromedial side of second part of duodenum at major duodenal papilla. Occasionally accessory duct might originate from proximal part of DPD and open into minor papilla. Sometimes two buds do not fuse and lead to pancreatic divisum. Abnormal rotation and fusion of buds might lead to annular pancreas. A few endodermal pancreatic evaginations may remain and migrate in bowel wall and form accessory(heterotopic) pancreas. Islets originating from DPB have more insulin synthesis. Neck, body and tail of pancreas is supplied by coeliac trunk. Derivatives of right VPB are supplied by branches of superior mesenteric artery. During rotation of VPB, superior mesenteric vessels(SMV) were engaged in between DPB and VPB. Lastly, SMV is located posterior to neck but it is anterior to uncinate process of pancreas. Detailed study of development of exocrine and endocrine portions is required for successful management of pathology of the pancreas.