The organ that makes insulin is the pancreas. It is located behind the stomach and functions as both an endocrine and exocrine gland. Within the pancreas, specialized clusters of cells called the islets of Langerhans contain beta cells that produce insulin

. Insulin is a hormone essential for regulating blood glucose levels. When blood sugar rises after eating, the beta cells in the pancreas release insulin into the bloodstream. Insulin helps transport glucose from the blood into the body's cells, where it is used for energy or stored, thus lowering blood sugar to a healthy level

. In summary:

• Organ: Pancreas
• Cells producing insulin: Beta cells in the islets of Langerhans
• Function of insulin: Regulates blood glucose by facilitating glucose uptake into cells