Explain how the human body responds when core body temperature rises above the normal level.

Eduqas GCSE Biology — 2.5.3 Homeostasis · Explain · 4 marks · View as Markdown

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

Model answer (4 marks)

Thermoreceptors in the skin and hypothalamus detect the rise in blood temperature.
The hypothalamic thermoregulatory centre signals the sympathetic nervous system to increase activity of sweat glands.
Sweat is secreted onto the skin surface and evaporates, taking heat energy with it.
Simultaneously, the hypothalamus causes vasodilation of cut‑tissue blood vessels, increasing heat loss by radiation.

Examiner tips

  • Use the exact terms: thermoreceptors, hypothalamus, sympathetic nervous system, sweat glands, evaporation, vasodilation.
  • Show the sequence: detection → signalling → sweat → evaporation → vasodilation.
  • Mention the effect of each step on heat loss.
  • Keep the answer concise – one sentence per point.

Mark scheme (4 marks)

  1. Thermoreceptors / the thermoregulatory centre in the hypothalamus detects the rise in blood temperature
  2. Sweat glands produce more sweat / increased sweating occurs
  3. Sweat evaporates from the skin surface, removing heat energy from the body
  4. Vasodilation occurs — blood vessels near the skin surface widen, increasing heat loss by radiation

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