AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
Information from receptors passes along cells (neurones) as electrical…
Full specification wording
Structure and function: Information from receptors passes along cells (neurones) as electrical impulses to the central nervous system (CNS).
When a receptor detects a stimulus, it generates an electrical impulse.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 3 of 13
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
When a receptor detects a stimulus, it generates an electrical impulse. This impulse travels along sensory neurones to the central nervous system, which consists of the brain and spinal cord. Sensory neurones are adapted to carry impulses rapidly: they are long, have branched endings to connect with receptors and other neurones, and are insulated by a myelin sheath that speeds up transmission. At synapses between neurones, the impulse triggers the release of a neurotransmitter that diffuses across the gap and stimulates the next neurone. The CNS processes the information and coordinates a response, which is then carried by motor neurones to effectors. This pathway allows the body to react quickly to changes in the internal and external environment.
What earns the marks
- Receptors detect stimuli and generate electrical impulses.
- Sensory neurones carry impulses from receptors to the CNS.
- The CNS is the brain and spinal cord and coordinates the response.
- Neurones are adapted with long fibres, branched endings and a myelin sheath.
- At synapses, neurotransmitters diffuse across the gap to pass the impulse on.
- Motor neurones carry impulses from the CNS to effectors.
Common mistakes and how to put them right
Saying information travels as a chemical along the whole neurone.
Put it right: It is electrical within a neurone and chemical at a synapse.
Thinking the CNS includes all nerves in the body.
Put it right: The CNS is the brain and spinal cord only.
Reversing the direction of travel.
Put it right: Sensory neurones carry impulses to the CNS, motor neurones carry impulses away from it.
Exam tips
- State the direction of impulse travel clearly: receptor to CNS to effector.
- Use the terms sensory neurone, relay neurone and motor neurone accurately.
- Mention the myelin sheath when explaining why transmission is fast.
Try the lesson
The start of the Structure and function: Information from receptors passes along cells (neurones) as electrical impulses to the central nervous system (CNS). lesson, made from checked teaching notes for this specification point.
Have a go first
Along which type of cell does information travel as an electrical impulse towards the CNS?
Listen
When a receptor detects a stimulus, it generates an electrical impulse. This impulse travels along sensory neurones to the central nervous system, which consists of the brain and spinal cord. Sensory neurones are adapted to carry impulses rapidly: they are long, have branched endings to connect with receptors and other neurones, and are insulated by a myelin sheath that speeds up transmission. At synapses between neurones, the impulse triggers the release of a neurotransmitter that diffuses across the gap and stimulates the next neurone. The CNS processes the information and coordinates a response, which is then carried by motor neurones to effectors. This pathway allows the body to react quickly to changes in the internal and external environment. A strong answer earns marks for these points. Receptors detect stimuli and generate electrical impulses. Sensory neurones carry impulses from receptors to the CNS. The CNS is the brain and spinal cord and coordinates the response. Neurones are adapted with long fibres, branched endings and a myelin sheath. A common slip: Saying information travels as a chemical along the whole neurone. Instead, it is electrical within a neurone and chemical at a synapse. Exam tip: State the direction of impulse travel clearly: receptor to CNS to effector.
See it
Put it in order
Put these steps in the order they happen.
- 1. Synapse: neurotransmitter diffuses across gap
- 2. Sensory neurone
- 3. Receptor detects stimulus
- 4. Effector
- 5. Motor neurone
- 6. CNS (brain and spinal cord) coordinates response
Key words
Say what each word means before you turn the card.
Electrical impulses
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Central nervous system
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Neurone adaptation
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See every definition
- Electrical impulses
- Information from receptors passes along cells (neurones) as these to the central nervous system.
- Central nervous system
- Consists of the brain and spinal cord, processes the information and coordinates a response.
- Neurone adaptation
- Neurones are long, have branched endings to connect with receptors and other neurones, and are insulated by a myelin sheath that speeds up transmission.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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