# A doctor is investigating a patient who has unusually high blood glucose levels throughout the day. The doctor suspects the patient's endocrine system is not functioning correctly. Explain how hormonal communication normally works in the body to regulate blood glucose levels, including how the hormone reaches its target organ.

> OCR A-Level Biology B — Advancing Biology (H422) — 5.8 Hormonal communication · Explain · 5 marks

> The endocrine system uses hormones to communicate between different parts of the body. Hormones are released directly into the bloodstream and travel to target organs where they produce an effect.

## Mark scheme (5 marks)

1. A gland (the pancreas) detects a change / stimulus (rise in blood glucose) and secretes a hormone (insulin)
2. The hormone is released directly into the bloodstream
3. The hormone travels in the bloodstream to the target organ (the liver / body cells)
4. Only the target organ responds because it has complementary receptors for that specific hormone
5. The target organ responds to lower blood glucose levels, e.g. the liver converts glucose to glycogen for storage

## Key terms

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

## Related

- [Revision notes for OCR A-Level Biology B — Advancing Biology (H422)](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-doctor-is-investigating-a-patient-b502cafe) · Published by Druglandscape Ltd.