# Nerve cells are adapted to carry electrical impulses quickly and efficiently. Describe four structural adaptations of a neurone and explain how each adaptation helps the neurone to carry out its function.

> WJEC A-Level Biology (Wales) — 4.6 The nervous system · Describe · 5 marks

## Mark scheme (5 marks)

1. The axon is surrounded by a myelin sheath (made of Schwann cells) which provides electrical insulation, speeding up the nerve impulse along the axon.
2. The axon is long, allowing the impulse to be carried over large distances quickly without crossing a synapse (which would slow it down).
3. The neurone has dendrites which pick up electrical impulses from other neurones, allowing the impulse to be received and passed on.
4. The neurone contains neurotransmitter substances which are released at synapses, allowing the impulse to continue into the next neurone.
5. Any one further valid point clearly linking a structural feature to its function — e.g. the cell body contains a nucleus and mitochondria to provide the energy (ATP) needed to maintain the impulse / produce neurotransmitters. (Accept any creditworthy point not already awarded.)

## Key terms

- [neurone](https://www.gradenine.co.uk/glossary/neurone)

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Source: [GradeNine](https://www.gradenine.co.uk/q/nerve-cells-are-adapted-to-carry-1b495a69) · Published by Druglandscape Ltd.