# A person has not drunk any water for several hours and their blood water concentration has fallen below the normal level. Explain how the kidneys respond to return blood water concentration to normal.

> Eduqas GCSE Biology — 4.3 Homeostasis in humans · Explain · 4 marks

## Mark scheme (4 marks)

1. The pituitary gland releases more ADH (antidiuretic hormone)
2. ADH travels in the blood to the kidneys
3. The kidneys reabsorb more water (back into the blood)
4. A smaller volume of more concentrated urine is produced

## Related

- [Revision notes for Eduqas GCSE Biology](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-person-has-not-drunk-any-c44512df) · Published by Druglandscape Ltd.