Human Pancreatic Islets of Langerhans Cells

Human Pancreatic Islets of Langerhans Cells or pancreatic islets cells, first discovered in the late-nineteenth century, are the regions of pancreas which contain endocrine cells producing hormone. Islet cells are innervated by sympathetic, parasympathetic, and sensory nerves. Although the islets only account for less than 2% of pancreatic mass, they are highly vascularized so that they can quickly secrete insulin in response to change glucose in blood. In addition, pancreatic islet cells can receive almost 10-15% of the blood-flow to the pancreas.
Langerhans cells are dense clusters of cells in the pancreas, comprising of different cell types. Pancreatic beta cells (or β cells) which function in insulin-secreting, are the most abundant islet cell type, encompassing around 60% of a human islet. There are also pancreatic alpha cells (or α cells) secreting glucagon, Delta cells (δ cells or D cells) secreting somatostatin, Epsilon cells (ε cells) secreting ghrelin and pancreatic PP cells that secret polypeptide. Those pancreatic cells together act on the maintenance of glucose homeostasis and other aspects of metabolism.