Describe the roles of receptors, coordination centres, and effectors in maintaining homeostasis.

AQA GCSE Biology (8461) — 4.5.1 Homeostasis · Describe · 4 marks · View as Markdown

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

Model answer (4 marks)

Receptors detect changes in the internal or external environment and send signals to coordination centres.
Coordination centres (e.g. brain, spinal cord, pancreas) receive and process the information.
Effectors (muscles or glands) respond to the signal and restore optimum conditions, reversing the change.

Examiner tips

Use the exact terms ‘receptors’, ‘coordination centres’ and ‘effectors’.
Show the flow: receptor → coordination centre → effector.
Keep each point brief to fit 4 marks.

Common mistakes

Confusing receptors with effectors; mixing up the order of the system.
Using vague language such as ‘organism’ instead of specific organs.

Mark scheme (4 marks)

Receptors detect stimuli / changes in the internal or external environment
Receptors send information / signals to coordination centres
Coordination centres (e.g. brain, spinal cord, pancreas) receive and process the information
Effectors (muscles or glands) bring about a response to restore optimum conditions / reverse the change

Key terms in this question

receptors · coordination centres · effectors · homeostasis