Islet Xenotransplantation: toward a cure for diabetes Windt, D.J. van der 2011-06-21 Doctoral Thesis

The pancreas is an organ with a central anatomical position in the abdomen, and a central role in the processes of food digestion and glucose metabolism. The vast majority of pancreatic tissue (more than 98%) is dedicated to the production and secretion of digestive enzymes that are released into the proximal small intestine, and therefore has an exocrine function. The remaining 1-2% is composed of cells producing mainly insulin (by beta cells) and glucagon (by alpha cells), hormones that are released into the bloodstream to regulate blood glucose levels. This small part of the pancreas therefore has an endocrine function. Those hormone-producing cells are organized in small clusters that appear as ‘small islands’ (islets) in the ‘sea’ of exocrine tissue (Figure 1), as first described by a German pathologist, Paul Langerhans, in 1869 while he was still a medical student, although at that time he was unaware of their function. When later their crucial role in glucose metabolism was discovered, they became known as islets of Langerhans, in the fields of diabetes and transplantation (Tx) simply referred to as ‘islets’.
http://repub.eur.nl/res/pub/23681/110621_Windt%2C%20Dirk%20Jan%20van%20der.pdf