the structure and function of neurones

structure of neurones overview

• Neurones send electrical and chemical messages around the body to sense organs

  • This information is then directed to the CNS

• A neurone is composed of:

  • The cell body - contains a nucleus

  • Dendrites - receive electrical signals from other neurones and transmit them to the cell body

  • Axon - carries the electrical charge away from the cell body down the length of the neurone and is covered in a fatty myelin sheath

  • Myelin sheath has gaps in it called Nodes of Ranvier which speed up the electrical signal’s transmission

  • Axon terminal - found at end of the neurone - plays a role in chemical transmission across the synaptic cleft to the next neurone

sensory neurones overview

• The role of sensory neurones is to send information from the peripheral nervous system (PNS) towards the central nervous system (CNS)

• Sensory neurones keep the brain informed about the external and internal environment information coming from the sense organs

• Sensory neurones can only transmit messages one way and cannot receive messages

• Sensory neurones have long dendrites and short axons

• The cell body is usually to the side of the cell

motor neurones overview

• The role of motor neurones is to carry signals from the CNS toward organs, muscles and glands (PNS)

• They can both transmit and receive messages

• Motor neurones control physical movements such as contraction/relaxation of muscles

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