Date Lecture) Subject
oral medicine Prof Sahar❖
Definition of Diabetes mellitus (DM): The term diabetes mellitus describes a metabolic disorder/syndrome of multiple etiology
characterized by chronic hyperglycemia with dysregulation of carbohydrate, fat and protein metabolism resulting from
defects in insulin secretion, insulin action due to problems of insulin receptors, or both affecting all
tissues of body especially eye, kidney, blood vessels and nerve .
Fasting blood glucose level (normal 70 – 110 mg/dl).
- After nutrition, most of food is transformed into glucose → circulation which is then utilized by the tissue cells for energy & function with the aid of insulin receptors acting on receptors on these cells.
- Insulin is produced by β
cells of the pancreas, and increased insulin secretion occurs in response to increased blood glucose concentration. Insulin binds to specific cellular receptors to exert its effects.
What happens in this figure ➢ Elevated blood glucose level → stimulate B cells of pancreas → insulin secretion → glucose is supplied to cells and the rest is stored in liver and muscles in the form of glycogen.
➢ Decreased blood glucose level → stimulate alpha cells of pancreas → glucagon secretion → converts glycogen stored in liver and muscles back into glucose in blood.
Hormonal feedback regulatory systems 
