Explain the roles of receptors, the central nervous system and effectors in producing a response to a stimulus.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Receptors detect a stimulus and convert it into an electrical impulse.
The impulse is transmitted to the central nervous system (brain and spinal cord).
The CNS processes the information and sends a response signal.
Effectors (muscles or glands) receive the signal and carry out the response.
The impulse is transmitted to the central nervous system (brain and spinal cord).
The CNS processes the information and sends a response signal.
Effectors (muscles or glands) receive the signal and carry out the response.
Examiner tips
- Use the exact sequence: receptor → CNS → effector
- Mention conversion to electrical impulse
- Show that CNS coordinates and sends the signal
- Keep answer concise and to the point
Common mistakes
- Confusing receptors with effectors
- Omitting the CNS step
- Using vague terms like "body" instead of "muscles or glands"
Mark scheme (4 marks)
- Receptors detect stimuli / changes in the environment
- Receptors send electrical impulses / information to the central nervous system (brain and spinal cord)
- The central nervous system coordinates / processes the information and sends impulses to effectors
- Effectors (muscles or glands) bring about the response
Key terms in this question
receptors · central nervous system · effectors
Related
- Revision notes: The human nervous system →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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