AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
The human nervous system: Students should be able to explain how the structure of the nervous system is adapted to its functions.
The nervous system carries information quickly between receptors and effectors.
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
The nervous system carries information quickly between receptors and effectors. Its structure matches this job. Sensory neurones run from receptors to the central nervous system, which is the brain and spinal cord; relay neurones connect within it; motor neurones carry impulses to effectors. Neurones are long so a single cell spans a distance, have branched endings to connect with many cells, and are insulated by a myelin sheath that speeds up impulse transmission. The spinal cord is a bundle of neurones protected by vertebrae, and reflex arcs pass through it so responses can occur without conscious brain processing. This makes reactions fast and automatic, which reduces harm.
What earns the marks
- Links sensory neurones to receptors and the central nervous system, and motor neurones to effectors.
- Explains that relay neurones connect sensory and motor neurones inside the central nervous system.
- Uses neurone length and branched connections to explain rapid communication across the body.
- Explains that the myelin sheath insulates the axon and increases the speed of impulse transmission.
- Explains that the spinal cord and reflex arc allow rapid, automatic responses that reduce injury.
Common mistakes and how to put them right
Saying impulses travel along the myelin sheath.
Put it right by stating that the impulse travels along the axon and the sheath speeds it up.
Confusing the roles of sensory and motor neurones.
Put it right by linking sensory to receptors and motor to effectors.
Claiming reflexes involve no nervous coordination.
Put it right by stating that reflexes use a reflex arc through the spinal cord, bypassing conscious decision-making.
Exam tips
- Structure your answer as feature → function, for example 'long axon → carries impulse a long distance in one cell'.
- Use the words receptor, coordinator, effector and impulse accurately to show correct sequence.
- When asked about speed, mention myelin and short synaptic gaps rather than vague words like 'fast'.
Try the lesson
The start of the The human nervous system: 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 motor neurone adapted to its function of transmitting electrical impulses?
Listen
The nervous system carries information quickly between receptors and effectors. Its structure matches this job. Sensory neurones run from receptors to the central nervous system, which is the brain and spinal cord; relay neurones connect within it; motor neurones carry impulses to effectors. Neurones are long so a single cell spans a distance, have branched endings to connect with many cells, and are insulated by a myelin sheath that speeds up impulse transmission. The spinal cord is a bundle of neurones protected by vertebrae, and reflex arcs pass through it so responses can occur without conscious brain processing. This makes reactions fast and automatic, which reduces harm. A strong answer earns marks for these points. Links sensory neurones to receptors and the central nervous system, and motor neurones to effectors. Explains that relay neurones connect sensory and motor neurones inside the central nervous system. Uses neurone length and branched connections to explain rapid communication across the body. Explains that the myelin sheath insulates the axon and increases the speed of impulse transmission. A common slip: Saying impulses travel along the myelin sheath. Instead, stating that the impulse travels along the axon and the sheath speeds it up. Exam tip: Structure your answer as feature → function, for example 'long axon → carries impulse a long distance in one cell'.
Key words
Say what each word means before you turn the card.
Central nervous system
Try answering aloud or in your head before turning the card.
Myelin sheath
Try answering aloud or in your head before turning the card.
Reflex arc
Try answering aloud or in your head before turning the card.
Motor neurones
Try answering aloud or in your head before turning the card.
See every definition
- Central nervous system
- The brain and spinal cord, which sensory neurones run to and relay neurones connect within.
- Myelin sheath
- Insulation around the axon that speeds up impulse transmission.
- Reflex arc
- A pathway through the spinal cord that lets responses occur without conscious brain processing, making reactions fast and automatic.
- Motor neurones
- Cells that carry impulses to effectors.
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of The human nervous system: Students should be able to explain how the structure of the nervous system is adapted to its functions.
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge