Diabetes
Laura Armstrong
Teacher
Recall Questions
This topic requires prior knowledge of blood glucose regulation. You can test your knowledge on this below.
What hormone decreases blood glucose concentration?
Insulin.
Which organ contains the islets of langerhans?
Pancreas.
What is homeostasis?
The maintenance of a stable internal environment within set limits, even when the external environment is changing.
Topic Explainer Video
Check out this @JoeDoesBiology video that explains diabetes or read the full notes below. Once you've gone through the whole note, try out the practice questions!
What Is Diabetes?
Diabetes mellitus is a condition where blood glucose concentration is not properly regulated, due to problems with insulin production or response.
If left untreated, it leads to:
- Hyperglycaemia (high blood glucose) which can then lead to high blood pressure and organ damage.
- Glucose in urine (glycosuria).
- Long-term damage to blood vessels, eyes, kidneys, and nerves.
Types of Diabetes
Type 1 Diabetes (Insulin-Dependent)
| Feature | Description |
| Cause | Autoimmune destruction of insulin-producing β cells in the pancreas. |
| Onset | Often in childhood or adolescence. |
| Insulin production | Absent. |
| Treatment | Regular insulin injections or insulin pump. |
| Risk factors | Genetic predisposition, possibly viral triggers. |
| Control | Careful monitoring of blood glucose, dietary control, insulin therapy. |
Key Point: Insulin is not produced so can be treated with insulin injections.
Type 2 Diabetes (Non-Insulin-Dependent)
| Feature | Description |
| Cause | Insulin receptors become less responsive (insulin resistance), sometimes reduced insulin secretion. |
| Onset | Typically in adults but increasingly in younger people due to obesity. |
| Insulin production | Reduced or normal, but less effective. |
| Treatment | Lifestyle changes; reduced carbohydrate, sugar and fat diet, increased exercise. |
| Risk factors | Obesity, lack of exercise, high sugar diet, genetics, age. |
| Control | Weight loss, exercise, dietary changes, medication to reduce absorption of glucose from the small intestine. |
Key Point: Can be prevented or reversed in early stages. Reduced insulin sensitivity so cannot be treated with insulin injections.
New Developments: Potential Cures
| Approach | Explanation |
| Stem cell therapy | Growing new β cells from stem cells to restore insulin production. |
| Pancreas transplant | Replaces faulty insulin production, but requires immunosuppression drugs. |
| Gene therapy | Experimental — aims to correct the autoimmune cause or improve insulin gene function. |
Key Terms
- Hyperglycaemia: Abnormally high blood glucose.
- Glycogenesis: Formation of glycogen from glucose.
- Glycogenolysis: Breakdown of glycogen to glucose.
- Gluconeogenesis: Formation of glucose from non-carbohydrates.
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Exam Tip
Be specific in describing the roles of insulin and glucagon. Avoid saying "insulin removes glucose" — instead say "increases uptake of glucose and conversion into glycogen".
No answer provided.
Explain why insulin injections are not an effective treatment for most people with Type 2 diabetes. (2 marks)
- In Type 2 diabetes, the body still produces insulin.
- The problem lies in insulin resistance — cells do not respond properly to insulin.
Practice Question
Try to answer the practice question from the TikTok on your own, then watch the video to see how well you did!