Structure and function of neurons

• Dendrites (post synaptic neuron)

  These are where the neurotransmitter receptors are found. Causes a new electrical impulse to form.
• Cell body

  Includes the nucleus which contains genetic material of the cell
• Axon

  Sends a nerve impulse (action potential) through the neuron to transmit a message to the next neuron
• Myelin sheath

  Protects the axon and helps to speed up transmission of the message
• Nodes of Ranvier

  Speeds up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon
• Terminal button -

  The end of the neuron and they send the information through to the next neuron, through the release of neurotransmitters.
• Sensory neurons -

  Location - The PNS in clusters known as ganglia

  Function - Send information from senses towards the brain. Receptors found in skin, eyes, ears and tongue.

  Structure - long dendrites and short axons

  Purpose - cover large surface area to get information from senses
• Relay neuron

  Location - Found in CNS

  Function - Carry nerve impulses between neurons allowing communication. Analyse sensations and decide how to respond.

  Structure - short dendrites, short axon and no myelin sheath

  Purpose - quickly send information from PNS to CNS
• Motor neuron

  Location - Cell bodies in CNS but long axons form part of the PNS

  Function - Send information via long axons from brain / spinal cord through to effectors eg muscles

  Structure - short dendrites and long axons

  Purpose - spread out - short dendrites to connect to one muscle