大象传媒

How does the nervous system help us respond? - OCR 21st CenturyAdaptations of neurons

Survival of an organism depends on its ability to respond to changes in the environment. The nervous system allows fast-acting but short-lived responses.

Part of Biology (Single Science)The human body - Staying alive

Adaptations of neurons

Nerve cells are called . They are adapted to carry electrical impulses from one place to another.

A bundle of neurons is called a .

An image of the inside of a nerve

The features of neurons help them to carry out their function efficiently:

  • they have a long fibre () so they can carry messages up and down the body over long distances
  • in a stimulated neuron, an electrical passes along the axon
  • the axon is insulated by a fatty (myelin) sheath - the fatty sheath increases the speed of the nerve impulses along the neuron
  • at each end of the neuron are tiny branches (), which branch even further into - the dendrites receive incoming nerve impulses from other neurons
Diagram of a motor neurone
Figure caption,
A motor neuron