- Regulation of blood glucose is an example of homeostasis
- The concentration of glucose in the blood must be kept within a narrow range
- Excessively high levels of glucose in the blood can lead to cells of the body losing water by osmosis, which can be dangerous
- Excessively low levels of glucose in the blood can lead to the brain receiving insufficient glucose for respiration, potentially leading to a coma or even death
- Blood glucose levels are regulated by the pancreas and the liver using hormones insulin and glucagon
- Insulin stimulates cells to take in glucose from the bloodstream (particularly liver and muscle cells)
- In liver and muscle cells excess glucose is converted into glycogen (a polymer of glucose) for storage
You should be able to extract information and interpret data from graphs that show the effect of insulin on blood glucose levels in people with and without diabetes.
Knowledge of the hormone glucagon is only required for higher tier candidates.
Type 1 diabetes
- Type 1 diabetes is a disorder in which the pancreas fails to produce sufficient insulin to control blood glucose levels
- Scientists think this is a result of a person’s own immune system destroying the cells of the pancreas that make insulin during development
- Type 1 diabetes is characterised by uncontrolled high blood glucose levels and is normally treated with insulin injections
Type 2 diabetes
- In Type 2 diabetes the body cells no longer respond to insulin produced by the pancreas - the person still makes insulin but their cells are resistant to it and don’t respond as well as they should
- This can also lead to uncontrolled high blood glucose levels
- Obesity is a big risk factor for Type 2 diabetes; probably because a person who is obese may consume a diet high in carbohydrates, and over-production of insulin results in resistance to it developing
- A carbohydrate-controlled diet and an exercise regime are common treatments for Type 2 diabetes
Table to compare type 1 and type 2 diabetes
It is common for students to confuse type 1 and types 2 diabetes and their treatments. Remember that insulin is only an effective treatment for type 1 diabetes because patients do not produce insulin of their own. Conversely, patients suffering with type 2 diabetes would not be treated with insulin as their cells are resistant to it and so it would make no difference to their symptoms.