Explain how negative feedback is involved in returning blood temperature to normal when a person becomes too hot.

Cambridge International IGCSE Biology (0610) — 14.4 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)

A rise in body temperature above the set point is detected by receptors in the hypothalamus and skin.
The hypothalamus sends signals to effectors such as sweat glands and blood vessels.
Sweating increases and vasodilation occurs, which removes heat from the body.
The body temperature falls back towards the set point; when it reaches normal the corrective response stops, completing the negative feedback loop.

Examiner tips

Use the word "receptors" and "hypothalamus" to show detection. Mention both sweating and vasodilation as effectors. Show the sequence: detection → signal → effector → temperature falls → loop stops.
Use the phrase "negative feedback loop" to demonstrate understanding of the mechanism.

Common mistakes

Failing to name the hypothalamus as the control centre. Omitting the effector responses such as sweating or vasodilation. Not explaining that the response stops once the set point is reached.

Mark scheme (4 marks)

A rise in body temperature above the set point is detected by receptors (in the hypothalamus / skin)
The hypothalamus / thermoregulatory centre sends instructions to effectors to lower body temperature (e.g. sweating increases / vasodilation occurs)
The effector response causes body temperature to fall back towards the set point / normal level
Once temperature returns to the set point, the corrective response is switched off / reduced, completing the negative feedback loop

Key terms in this question

negative feedback