AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
Students should be able to explain how the structure of the nervous system…
Full specification wording
Structure and function: Students should be able to explain how the structure of the nervous system is adapted to its functions.
The nervous system is adapted to detect changes and coordinate rapid responses.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 1 of 13
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
The nervous system is adapted to detect changes and coordinate rapid responses. Receptors such as those in the skin, eye and tongue detect stimuli and generate electrical impulses. Sensory neurones carry impulses to the central nervous system, where relay neurones connect sensory and motor pathways. Motor neurones carry impulses to effectors, which are muscles or glands. Neurones are adapted by being long, so they carry impulses over long distances, and by having branched endings that connect to many other cells. The myelin sheath insulates the axon and speeds up impulse transmission. Synapses are tiny gaps where a neurotransmitter diffuses across to pass the impulse to the next neurone, ensuring one-way transmission. These features allow fast, targeted coordination of behaviour.
What earns the marks
- Receptors detect stimuli and initiate electrical impulses.
- Sensory neurones carry impulses to the CNS; motor neurones carry impulses away to effectors.
- Relay neurones connect sensory and motor neurones within the CNS.
- Neurones are long and branched to carry impulses over long distances and form many connections.
- The myelin sheath insulates the axon and increases the speed of impulse transmission.
- Synapses use neurotransmitters that diffuse across a gap, allowing one-way transmission.
Common mistakes and how to put them right
Saying impulses travel along a neurone as a chemical signal.
Put it right: Within a neurone the impulse is electrical, and at a synapse it is chemical.
Confusing sensory and motor neurones.
Put it right: Sensory neurones carry impulses towards the CNS, motor neurones carry impulses away from the CNS.
Thinking the myelin sheath generates the impulse.
Put it right: It insulates the axon and speeds up transmission.
Exam tips
- Link each structural feature directly to the function it performs.
- Use correct terms such as receptor, effector, synapse and neurotransmitter.
- When describing a reflex, state the direction of impulse travel from receptor to effector.
Try the lesson
The start of the Structure and function: Students should be able to explain how the structure of the nervous system is adapted to its functions. lesson, made from checked teaching notes for this specification point.
Have a go first
How is the structure of a neurone adapted to its function of transmitting electrical impulses quickly across the body?
Listen
The nervous system is adapted to detect changes and coordinate rapid responses. Receptors such as those in the skin, eye and tongue detect stimuli and generate electrical impulses. Sensory neurones carry impulses to the central nervous system, where relay neurones connect sensory and motor pathways. Motor neurones carry impulses to effectors, which are muscles or glands. Neurones are adapted by being long, so they carry impulses over long distances, and by having branched endings that connect to many other cells. The myelin sheath insulates the axon and speeds up impulse transmission. Synapses are tiny gaps where a neurotransmitter diffuses across to pass the impulse to the next neurone, ensuring one-way transmission. These features allow fast, targeted coordination of behaviour. A strong answer earns marks for these points. Receptors detect stimuli and initiate electrical impulses. Sensory neurones carry impulses to the CNS; motor neurones carry impulses away to effectors. Relay neurones connect sensory and motor neurones within the CNS. Neurones are long and branched to carry impulses over long distances and form many connections. A common slip: Saying impulses travel along a neurone as a chemical signal. Instead, within a neurone the impulse is electrical, and at a synapse it is chemical. Exam tip: Link each structural feature directly to the function it performs.
Key words
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Structure and function
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Rapid coordination
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Neurone adaptation
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Synaptic transmission
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See every definition
- Structure and function
- The nervous system is adapted to detect changes and coordinate rapid responses, with receptors detecting stimuli and generating electrical impulses.
- Rapid coordination
- Features of the nervous system allow fast, targeted coordination of behaviour.
- Neurone adaptation
- Neurones are long so they carry impulses over long distances, and have branched endings that connect to many other cells.
- Synaptic transmission
- Synapses are tiny gaps where a neurotransmitter diffuses across to pass the impulse to the next neurone, ensuring one-way transmission.
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