Which organ secretes insulin?

• A. Liver
• B. Pancreas
• C. Stomach
• D. Kidneys

Answer: (B)

Insulin is a hormone produced by the pancreas, specifically by the beta cells in the islets of Langerhans. Its main job is to regulate blood glucose: it signals muscle and fat cells to take in glucose from the bloodstream and it also helps the liver store excess glucose as glycogen, lowering blood sugar after meals. The pancreas has an endocrine role (releasing hormones like insulin and glucagon) and an exocrine role (secreting digestive enzymes into the small intestine). The other organs listed do not produce insulin themselves—the liver mainly stores and metabolizes glucose, the stomach releases digestive juices and certain hormones, and the kidneys filter blood and manage fluid and electrolyte balance. Understanding this helps connect how a rise in blood glucose after eating prompts insulin release to restore normal levels.