Lecture 3: insulin and diabetes. The pancreas, gonads, and most other organs secrete hormones. Tucked right under the stomach. Mixed gland composed of both endocrine and exocrine gland cells. Develops as outpocketing of the epithelial lining of the gastrointestinal tract. Acinar cells: produce enzyme- rich juice that is carried by ducts to the small intestine during digestion. Pancreatic islets: tiny cell clusters that produce pancreatic hormones: two major populations, alpha cells: glucagon- synthesizing (glucagon, beta cells: insulin- synthesizing (insulin) If excess glucose is still available, it is converted to fat: factors affecting insulin release: Elevated blood glucose levels. Rising blood levels of amino acids and fatty acids. Acetylcholine released by parasympathetic nerve fibers. Hyperglycemic hormones: hyperglycemia: body no longer taking up the glucose from the blood, so blood glucose levels are high. Normal: insulin binds to receptor, and allows vesicles to fuse to cell membrane, which allows glucose to come in. However, this doesn"t happen with hyperglycemia.