Human Anatomy Part 1 - K. A. Dyubenko, A. K. Kolomiyytsev, Yu. B. Chaykovsky 2002

Special Part
Splanchnology, splanchnologia [the study of viscera] - Development of the digestive and respiratory systems
Development of the pancreas

The pancreatic primordium appears simultaneously with the Liver bud in the same region. It consists of two parts: a dorsal part, formed by the endoderm of the posterior wall of the duodenum which grows into the dorsal mesentery, and a ventral part (see Fig. 278) that develops from the hepatic diverticulum and penetrates the ventral mesentery. The dorsal bud grows faster than the ventral one. It communicates with the intestine via the accessory pancreatic duct (duct of Santorini), whereas the ventral bud does so via the main pancreatic duct (duct of Wirsung). Due to the Displacement of the gut associated with its rotation, as well as the rapid growth of the liver, the ventral bud shifts to the DORSAL SIDE OF the intestine and fuses with the dorsal bud during the seventh week. As a result, the duct of Wirsung typically persists and opens into the duodenal lumen at the major duodenal papilla (Vater's papilla) alongside the common Bile duct, while the duct of Santorini regresses.

By the third month of embryonic development, the exocrine and endocrine Components of the organ begin to form. In the exocrine portion, the excretory ducts develop first, followed later by the secretory units (acini). The endocrine components segregate from the exocrine tissue and differentiate into pancreatic islets (islets of Langerhans) interspersed among the acini. The Connective Tissue of the Pancreas derives from its mesenchymal component, whereas the epithelium of both the exocrine and endocrine parts, as well as the excretory ducts, originates from the endoderm.