# Homeostasis

Keeping the internal conditions of the body within a narrow range, such as temperature, blood sugar and water level. Most of it uses negative feedback: a change triggers a response that reverses the change.

Biology (university) · Part 09: Animal physiology · Card 1 of 9 · Last updated 2026-10-19

## Analogy

A thermostat that heats or cools to stay near a set point.

## In practice

When you get too hot, you sweat and your skin blood vessels widen, which cools you down.

## Practice

### Flashcards

- **What is negative feedback?** A response that reverses a change and returns a condition to its set point.

### Interview questions

**Explain how negative feedback regulates blood glucose, naming the hormones and organs involved.**

- Pancreas detects rise
- Insulin released, cells and liver take up glucose
- Glucose falls
- Glucagon released when low, liver releases glucose

## Questions people ask

### What is the difference between positive and negative feedback?

Negative feedback reverses a change, keeping conditions steady, like a thermostat. Positive feedback amplifies a change, pushing the system further. It is rarer. Childbirth is an example: contractions release oxytocin, which causes stronger contractions, and the loop stops only when the baby is born.

### How does the body control temperature?

The brain's hypothalamus acts as a thermostat. If you are too hot, you sweat and blood vessels in your skin widen to lose heat. If you are too cold, you shiver, blood vessels narrow and hairs stand up. These responses return the body to about 37 degrees Celsius.

## Related concepts

- [Hormone](https://studyvisually.com/learn/science/biology-university/biology-university-part-9/biology-university-part-9-concept-4)
- [Nephron](https://studyvisually.com/learn/science/biology-university/biology-university-part-9/biology-university-part-9-concept-7)

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