Pancreatic cells. Fluorescent light micrograph of cells in an islet of Langerhans in the pancreas. The islets of Langerhans contain the endocrine (hormone secreting) cells,of the pancreas. Beta cells,which secrete insulin,are red,alpha cells,which secreted glucagon,are yellow,and the nuclei of other cells are blue. Insulin and glucagon both regulate blood sugar levels. Insulin is released when blood sugar is high and instructs liver,muscle and fat cells to absorb glucose and store it as glycogen or fat. Glucagon is released when blood sugar is low,and instructs the liver to release stored glucose,or synthesise extra glucose |