Neurones

• Sensory neurone

  • Short axon
  • 1 long dendrite
  • Carries A.P from receptor -> CNS
  • Cell body is at the middle of the axon

  
• Motor neurone

  • Long axon
  • Many medium length dendrites
  • CNS -> effector

  
• Relay neurone

  • Variable axon
  • Variable dendrite
  • Sensory -> motor via CNS

  
• how do myelinated neurones increase transmission velocity

  • Contains schwann cells wrapped around axons
  • Insulating layer
  • Impulse jumps from node to node
  • So depolarisation only needs to happen at nodes of Ranvier
  • Saltatory conduction
• 2 factors that increase transmission velocity

  • High temp - increases KE of ions = faster diffusion
  • Axon has large diameter - large SA for diffusion of ions