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