Describe how a nerve impulse travels from a receptor to an effector in a simple reflex arc.

Eduqas GCSE Biology — 4.1 Nervous coordination and control in humans · Describe · 4 marks · View as Markdown

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

Model answer (4 marks)

Receptor detects a stimulus

Impulse travels along a sensory neurone to the spinal cord / relay neurone

Impulse passes across a synapse / from one neurone to the next

Motor neurone carries impulse to the effector, which responds

Examiner tips

  • Use the word ‘receptor’ first, then ‘sensory neuron’, ‘synapse’, ‘motor neuron’, and finish with the effector.
  • Show the sequence clearly – a short list or numbered points is acceptable.
  • Use UK spelling (neuron, not neuron).

Common mistakes

  • Mixing up the order of sensory and motor neurons
  • Omitting the synapse step
  • Using ‘nerve’ instead of ‘neuron’

Mark scheme (4 marks)

  1. Receptor detects a stimulus
  2. Impulse travels along a sensory neurone to the spinal cord / relay neurone
  3. Impulse passes across a synapse / from one neurone to the next
  4. Motor neurone carries impulse to the effector, which responds

Key terms in this question

receptor · effector

Related

More Nervous coordination and control in humans questions

▶ Try answering this question with AI marking (free) →