Homeostasis: blood glucose, temperature and negative feedback
Learn how the body keeps conditions steady, how insulin and glucagon control blood glucose and what happens in diabetes, with examples.
GCSEHigh SchoolAPCurriculum fit: GCSE Biology and Combined Science (homeostasis and response). US: high school life science (feedback mechanisms and homeostasis).
On this page
What is it?
Homeostasis means keeping the internal conditions of the body steady, such as temperature, water content and blood glucose. It works through negative feedback: when a level changes, the body triggers a response that reverses the change.
Hormones are chemical messengers released into the blood by glands. They travel to target organs, producing slower but longer-lasting effects than nerve impulses.
Key formulas and ideas
- Negative feedback: a change is detected, and a response brings the level back to normal.
- Blood glucose: insulin (from the pancreas) lowers it; glucagon raises it.
- Body temperature is monitored by the thermoregulatory centre in the brain.
Worked examples
Example 1: After a meal
Question: Explain what happens to blood glucose after a carbohydrate-rich meal.
- Blood glucose rises.
- The pancreas releases insulin.
- Insulin makes liver and muscle cells take in glucose and convert it to glycogen.
- Blood glucose falls back to normal.
Answer: Insulin lowers blood glucose by storing it as glycogen
Example 2: Hot day
Question: How does the body respond to being too hot?
- Sweat glands release sweat, which cools the skin as it evaporates.
- Blood vessels near the skin widen (vasodilation), so more heat is lost.
Answer: Sweating and vasodilation
Example 3: Diabetes
Question: Compare type 1 and type 2 diabetes.
- In type 1 the pancreas does not make enough insulin.
- In type 2 the body's cells stop responding properly to insulin.
Answer: Type 1: lack of insulin. Type 2: insulin resistance
Common mistakes
- Confusing insulin and glucagon.
- Describing positive feedback instead of negative feedback.
- Saying the body 'burns' glycogen. Glycogen is converted back to glucose.
- Writing that hormones travel in the nervous system.
Practice questions
Frequently asked questions
How are hormones different from nerves?
Hormones travel in the blood and have slower, longer-lasting effects. Nerve impulses are fast and short-lived.
Why does body temperature need to stay near 37 °C?
Enzymes work best at this temperature, so large changes slow or stop reactions in cells.
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Reviewed by StudyMorrow editorial review on 5 Nov 2026.