Explore the intricate process of insulin synthesis and secretion in this comprehensive medical lecture. Delve into the structure and function of the pancreas, focusing on the Islets of Langerhans and their cellular composition. Learn about the roles of different cell types, including B cells, A cells, and D cells, and their respective hormone productions. Examine the blood supply to the islets and its impact on hormone distribution. Understand the complex journey from pre-proinsulin to biologically active insulin, including the genetic and cellular processes involved. Discover the storage mechanisms of insulin and the factors triggering its release. This in-depth exploration provides essential knowledge for medical students and professionals in the field of endocrinology and diabetes management.