Explain how adrenaline prepares the body for a 'fight-or-flight' response. In your answer, name the gland that releases adrenaline and describe the effects it has on the body.

Eduqas A-Level Biology — 4.3 Variation and evolution · Explain · 5 marks · View as Markdown

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

A student is about to step onto a stage to perform in front of a large audience. They notice their heart is beating faster and they feel more alert.

Model answer (5 marks)

Adrenaline is released by the adrenal gland.
1. It increases heart rate and pulse.
2. It raises breathing rate.
3. It stimulates the conversion of glycogen into glucose.
4. The glucose and oxygen are made more available for cellular respiration.
5. This supplies extra energy to the muscles for a fight‑or‑flight response.

Examiner tips

  • Use the exact terms: adrenal gland, heart rate, breathing rate, glycogen, glucose, respiration, energy.
  • Show the sequence: release → physiological changes → energy supply.
  • Keep each point brief but complete to hit all 5 marks.

Common mistakes

  • Mixing up adrenal gland with pituitary gland.
  • Failing to mention both glucose and oxygen availability.
  • Omitting the conversion of glycogen into glucose.

Mark scheme (5 marks)

  1. Adrenaline is released by the adrenal gland
  2. Heart rate / pulse rate increases
  3. Breathing rate increases
  4. Glycogen is converted into glucose
  5. More glucose / oxygen is available for respiration to provide energy (for muscles)

Key terms in this question

adrenaline · fight-or-flight

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