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Nerve Cells

Biology: AQA GCSE Higher, topic 1.1.17

Nerve Cell (Neurone)

Nerve cells (or neurones) are specialised to transmit electrical messages around the body. Some key features are:

Axon

Axon

  • Part of the cell that electrical signals travel along.
  • Nerve cells have a long axon. This increases the distance that electrical signals can travel.
Myelin sheath

Myelin sheath

  • A sheath made of a material called myelin surrounds the axon of the nerve cell. This stops the electrical nerve signals leaking out of the nerve cell.
  • This increases the speed of transmission (travel) of electrical signals.
Dendrites

Dendrites

  • Branches of a nerve cell.
  • Several dendrites spread outwards from the cell body to transfer electrical messages to other neurons.
  • Electrical messages travel between neurons at synapses.

Test yourself on Nerve Cells

  • Why are nerve cells adapted with both a long axon and a myelin sheath?

  • What name is given to the gaps between nerve cells where messages pass from one neurone to another?

  • How does the myelin sheath affect the transmission of electrical signals along a nerve cell?

  • Roughly how long does it take for an electrical impulse to travel through a nerve cell?

  • Which nerve cell structure allows electrical impulses to travel in a fraction of a second?

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