Explain how adrenaline prepares the body for a 'fight or flight' response.

AQA GCSE Biology (8461) — 4.5.3 Hormonal coordination in humans · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

A student is walking home alone at night and suddenly hears a loud noise behind them. Their adrenal glands immediately release a hormone into the bloodstream.

Model answer (4 marks)

Adrenaline is released by the adrenal glands when a person feels fear or stress.

It increases the heart rate.

The faster heart pumps more blood, delivering more oxygen and glucose to the brain and muscles.

This prepares the body for rapid action – either to confront the threat or to escape it (fight or flight).

Examiner tips

Use the exact phrase "adrenaline is released by the adrenal glands" for the first point. Show the chain: adrenaline → ↑ heart rate → ↑ blood flow → ↑ oxygen/glucose → rapid action. Keep each point short and separate to match the 4 marks.

Common mistakes

Mixing up adrenaline with cortisol or other hormones. Using vague terms like "stress hormones" instead of specifying adrenaline. Failing to mention the increase in heart rate or the delivery of oxygen/glucose.

Mark scheme (4 marks)

Adrenaline is produced by the adrenal glands (in response to fear or stress)
Adrenaline increases the heart rate
This boosts the delivery of blood (oxygen/glucose) to the brain and muscles
This prepares the body for rapid action / to either confront or escape the threat (fight or flight)

Key terms in this question

adrenaline