Everything on the GCSE Biology Blood Glucose & Diabetes poster is written out below, section by section. Use it to search the sheet, copy parts into your own notes, or check a fact quickly.
The pancreas is the sensor
The pancreas continuously monitors blood glucose levels. If they drift too high or too low, the pancreas releases a hormone to bring the level back to normal.
When blood glucose is too low
This happens, for example, after exercise or fasting.
- The pancreas releases glucagon.
- Glucagon tells the liver to convert stored glycogen back into glucose.
- Glucose is released into the blood.
- Blood glucose rises back to normal.
When blood glucose is too high
This happens, for example, after a meal.
- The pancreas releases insulin.
- Insulin tells the liver and muscle cells to absorb glucose from the blood.
- The cells convert glucose into glycogen for storage.
- Blood glucose falls back to normal.
Negative feedback
This is negative feedback - whenever levels drift, the body acts to push them back. Blood glucose is kept steady day or night, whether full or fasting.
Blood glucose over time
Blood glucose levels oscillate gently around a set point (about 90 mg/100 ml). The level rises after meals and dips between them, but the hormones continuously correct any deviation back towards that set point.
Diabetes
| Type 1 | Type 2 | |
|---|---|---|
| Cause | Pancreas does not produce enough (or any) insulin | Body cells stop responding properly to insulin |
| Who gets it | Usually starts in childhood - autoimmune cause | Usually develops in adulthood - strongly linked to obesity |
| Treatment | Insulin injections with meals | Carbohydrate-controlled diet and regular exercise - medication if needed |