A rise in blood glucose is sensed by beta cells in the islets of Langerhans in the pancreas. As glucose is metabolised by the islet cells, this produces energy (ATP) that then activates multiple signalling events, finally leading to insulin release from islet cells. The greater the rise in glucose above the setpoint, the more the insulin secreted. Insulin is carried by the bloodstream to its target organs. In organs such as skeletal muscle, adipose (fat) and liver, insulin initiates responses that convert glucose into long-term energy stores (anabolism) or use it immediately as fuel for cellular functions.
Patients with diabetes mellitus have abnormally high blood glucose levels. This arises when the pancreas’s ability to produce insulin is impaired (Type 1), or target organs are less responsive to insulin, even if insulin is being produced by the pancreas (Type 2).
IMPORTANT: This resource assumes basic knowledge of insulin and diabetes mellitus as taught in A Level Biology. It aims to build on that understanding in exploring:
1. The typical profile of a patient with Type 2 diabetes mellitus,
2. The biology behind the symptoms and complications of Type 2 diabetes mellitus,
3. Proposed mechanisms of insulin resistance in Type 2 diabetes mellitus, as compared to insulin resistance in other diseases,
4. Treatments for insulin resistance.
Work through the activities below to find out more about diabetes.