Mechanical Protection
  • Provides buoyancy and cushioning
  • Reduces the effective weight of the brain
  • Protects against deformation caused by acceleration and deceleration
Maintenance of Constant Environment
  • Maintains a constant ionic and osmotic environment for neuronal cells
  • Essential for the functioning of normal neuronal activity
Regulation of ICP
  • Displacement of CSF into spinal canal provides important, though limited, compensation for increases in ICP ('Spatial compensation')
Control of Respiration
  • Central chemoreceptors detect changes in CSF pH caused by variations in CO2 levels resulting in the respiratory centre adjusting respiratory rate and tidal volumes
  • CO2 freely dissolves in CSF from blood given its lipid solubility and low molecular weight
  • Comparatively low protein levels in CSF reduce buffering capacity making CSF pH very sensitive to changes in blood pCO2
Clearance of Waste Products
  • The brain lacks a lymphatic system to cleat waste products (extracellular proteins excess fluid and metabolic waste)
  • A specialised 'glymphatic system' circulates CSF in paravascular channels where waste products are removed