part of part of has part has part develops_from contributes to morphology of exocrine pancreas AAO:0010407 BTO:0000434 CALOHA:TS-1241 EMAPA:35328 EV:0100093 FMA:16017 In the hagfish and lampreys (our most primitive vertebrate species of today), the first sign of 'a new organ' is found as collections of endocrine cells around the area of the bile duct connection with the duodenum. These endocrine organs are composed of 99% beta cells and 1% somatostatin-producing delta cells. Compared to the more primitive protochordates (e.g. amphioxus), this represents a stage where all previously scattered insulin-producing cells of the intestinal tissue have now quantitatively migrated to found a new organ involved in sensing blood glucose rather than gut glucose. Only later in evolution, the beta cells are joined by exocrine tissue and alpha cells (exemplified by the rat-, rabbit- and elephant-fishes). Finally, from sharks and onwards in evolution, we have the islet PP-cell entering to complete the pancreas.[well established][VHOG] MA:0002415 TAO:0001249 The exocrine pancreas is composed of acinar epithelial cells and ductal epithelium that manufacture the proteolytic enzymes and bicarbonate required for digestion.[TAO] The part of the pancreas that acts as an exocrine gland, consisting of the pancreatic acini, which produce pancreatic juice and secrete it into the intestine to aid in protein digestion. [TFD][VHOG] The part of the pancreas that is part of the exocrine system and which produces and store zymogens of digestive enzymes, such as chymotrypsinogen and trypsinogen in the acinar cells [GO]. UBERON:0000017 UMLS:C0553695 VHOG:0000048 XAO:0000137 ZFA:0001249 exocrine component of pancreas exocrine pancreas exocrine part of pancreas pars exocrina pancreatis uberon serous gland pancreatic acinus pancreas exocrine system ventral pancreatic bud endoderm-derived structure trunk region element pancreatic duct