create a separate class for distributed pancreas, eg cyclostomes?

The part of the pancreas that acts as an endocrine gland, consisting of the islets of Langerhans, which secrete insulin and other hormones. [TFD][VHOG], The zebrafish endocrine pancreas is composed of small groups of islet cells that are distributed throughout the exocrine pancreas. The islet cells produce insulin, glucagon and somatostatin.[TAO]

uberon

islets of Langerhans part of pancreas, endocrine part of pancreas

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]

UBERON:0000016

endocrine and exocrine pancreas are not co-associated in hagfishes or lampreys

• islet of Langerhans

• pancreas

• islet of Langerhans
• secretion of endocrine pancreas