Neuronal structure, function and organisation

• Neuron structure

  A) dendrite

  B) cell body

  C) axon

  D) myelin

  E) presynaptic terminal

  
• Neurons are post mitotic

  • limited repair/regeneration
  • plasticity occurs but is not completely restorative
• Neurons have high metabolic activity
• Neurones are extremely long and therefore vulnerable if axonal transport is affected
• There is high levels of protein expression on neuronal cell membranes (auto-antigens)
• Activated microglia

  • ameboid shape
  • processes fewer, shorter, thicker
  • release signaling molecules
• Activated microglia release

  • reactive oxygen species
  • reactive nitrogen species
  • proinflammatory cytokines
  • matrix metalloproteinases
  • neurotrophic factors
• Resting microglia

  • microglial processes constantly sample local environment
  • microglial processes make frequent contact with synapses and sense synaptic activity
  • synapse remodeling and removal plays a role in synaptic plasticity
• Cholinergic nerve cell bodies and projections contain ACh.
• The soma (cell bodies) of neurones are found within the grey matter, whereas the axons are found in the white matter.
• Dorsal root of spinal cord - sensory fibres in
• Ventral root of spinal cord - motor fibres out
• Axons are surrounded by an endoneurium
• Axons are bundled into fascicles surrounded by a perineurium
• Fascicles are bundled into nerves, surrounded by an epineurium
• Blood vessels run alongside fascicles within a nerve