# A doctor explains to a patient that their body constantly monitors and adjusts internal conditions. The doctor describes two systems that the body uses to communicate and respond to changes: the nervous system and the endocrine system. Compare how the nervous system and the endocrine system communicate information around the body.

> OCR A-Level Biology B — Advancing Biology (H422) — 5.5 Communication and homeostasis · Compare · 5 marks

> The human body must maintain a stable internal environment despite changes in external conditions. Two major communication systems help achieve this: the nervous system, which uses electrical impulses, and the endocrine system, which uses chemical messengers released into the blood.

## Mark scheme (5 marks)

1. The nervous system uses electrical impulses / nerve impulses, whereas the endocrine system uses hormones / chemical messengers
2. Nervous system signals travel along neurones / nerves, whereas endocrine system hormones travel in the bloodstream
3. The nervous system produces a fast response, whereas the endocrine system produces a slower response
4. The nervous system produces a short-lived / brief response, whereas the endocrine system produces a longer-lasting response
5. The nervous system produces a localised / specific response (acts on a specific effector / muscle or gland), whereas the endocrine system can produce a widespread response (hormones travel throughout the body / act on target organs)

## Key terms

- [nervous system](https://www.gradenine.co.uk/glossary/nervous-system)
- [endocrine system](https://www.gradenine.co.uk/glossary/endocrine-system)

## Related

- [Revision notes for OCR A-Level Biology B — Advancing Biology (H422)](https://www.gradenine.co.uk/learn)
- [How to answer "Compare" 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-doctor-explains-to-a-patient-c103687f) · Published by Druglandscape Ltd.