Name the gland which secretes insulin hormone.

The pancreas is the gland that secretes insulin hormone. More specifically, specialized clusters of cells within the pancreas called the islets of Langerhans (or pancreatic islets) produce this crucial hormone. Within these islets, beta cells are responsible for synthesizing and releasing insulin in response to elevated blood glucose levels.

Insulin plays a vital role in regulating blood sugar by enabling cells throughout the body to absorb glucose from the bloodstream and use it for energy or storage. When the pancreas fails to produce sufficient insulin or when the body's cells become resistant to its effects, diabetes mellitus develops. This is why people with Type 1 diabetes require insulin injections—their pancreatic beta cells have been damaged and can no longer produce this essential hormone. The pancreas also functions as an exocrine gland, producing digestive enzymes, making it a dual-function organ.