Edexcel IGCSE Biology · Spec 2.87-2.90
Nervous System and Reflexes
The central nervous system, the reflex arc, and how synapses pass impulses between neurones.
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Nervous System and Reflexes
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Spec 2.87-2.90
What you need to know
- Describe the nervous system and its neurones
- Describe a reflex arc
- Explain how synapses work
Active recall
Quick check
Answer each question before opening the answer.
Give the order of a reflex arc.
Stimulus → receptor → sensory neurone → relay neurone (CNS) → motor neurone → effector → response.
Why are reflex actions fast and automatic?
They do not involve conscious thought by the brain, which protects the body from harm quickly.
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