neurons

• neuron


  basic building blocks of the nervous system

  nerve cells that process and transmit messages through electrical and chemical signals
• types of neurons

  sensory neuron

  relay neutron

  motor neuron
• sensory neuron

  long dendrites

  short axon
• sensory neuron function

  carry messages from the PNS to the CNS
• relay neuron

  short dendrites

  short axons
• relay neuron function

  connect the sensory neuron to motor or other relay neurons
• motor neuron

  short dendrites

  long axons
• motor neuron function

  connects CNS to effectors such as muscles or glands
• cell body(stoma) definition

  includes a nucleus which contains the genetic material of the cell
• dendrites definition

  branchlike structures

  carry nerve impulses from neighbouring neurons towards the cell body
• axon definition

  carries impulses away from the cell body down the length of the neuron
• myelin sheath

  fatty layer covering the axon

  protects the axon

  speeds up electrical transmission of the impulse
• nodes of ranvier definition

  gaps in the myelin sheath

  speeds up the transmission of the impulse

  force impulse to jump across the gaps
• terminal buttons definition

  the end of the axon

  communicate with the next neuron in the chain across a gap known as the synapse
• location of motor neuron

  cell bodies may be in CNS

  but have long axons which form part of PNS
• sensory neurons location

  in the PNS in clusters called ganglias
• relay neurons location

  make up 97% of neurons

  found in the brain and visual system