# Hormone

A chemical messenger made in a gland and carried by the blood to a target organ.

Biology (school) · Part 03: The human body · Card 9 of 11 · Last updated 2026-10-19

## Analogy

A letter in the post, slower than a phone call but longer lasting.

## In practice

Insulin, made in the pancreas, tells the liver to store glucose.

## Practice

### Flashcards

- **Which gland controls blood glucose with insulin?** The pancreas.

### Interview questions

**Describe how blood glucose is kept steady after a meal.**

- Glucose rises after eating
- The pancreas releases insulin
- Insulin makes the liver store glucose as glycogen
- Blood glucose falls back to normal, which is negative feedback

## Questions people ask

### How are hormones different from nerve signals?

Nerve signals are electrical impulses that act very fast and for a short time on a precise place. Hormones travel in the blood, so they act more slowly, but their effects last longer and can reach many organs. Nervous responses are for urgent reactions, hormones for longer changes.

### What is the difference between type 1 and type 2 diabetes?

In type 1 diabetes, the pancreas stops making enough insulin, so patients inject insulin. In type 2, the body cells stop responding well to insulin. This is linked to obesity and is often managed with diet and exercise. Both lead to high blood glucose if untreated.

## Related concepts

- [Negative feedback](https://studyvisually.com/learn/science/biology-school/biology-school-part-3/biology-school-part-3-concept-11)
- [Homeostasis](https://studyvisually.com/learn/science/biology-school/biology-school-part-3/biology-school-part-3-concept-10)

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