# A patient is told by their doctor that their pituitary gland has stopped producing ADH. Explain what effect this would have on the patient's kidneys and the composition of their urine.

> WJEC A-Level Biology (Wales) — 4.5 Homeostasis and the kidney · Explain · 5 marks

## Mark scheme (5 marks)

1. ADH normally increases the permeability of the kidney tubules to water
2. Without ADH, the kidney tubules remain less permeable to water / water is not reabsorbed
3. A larger volume of urine is produced
4. The urine produced is more dilute / contains more water
5. The patient may become dehydrated because water is lost in the urine rather than being retained in the blood

## Key terms

- [ADH](https://www.gradenine.co.uk/glossary/adh)
- [pituitary gland](https://www.gradenine.co.uk/glossary/pituitary-gland)
- [urine](https://www.gradenine.co.uk/glossary/urine)

## Related

- [Revision notes for WJEC A-Level Biology (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-patient-is-told-by-their-fb66e1e7) · Published by Druglandscape Ltd.