Ventricles & CSF

Summary

  • Ventricles of the brain
    • CSF

Ventricles of the brain

  • This are cavities within the brain filled with CSF
  • 4 ventricles to consider:
    1. Two lateral ventricles (1st and 2nd)
    2. 3rd ventricle 
    3. 4th ventricle
    4. From https://commons.wikimedia.org/wiki/File:Blausen_0896_Ventricles_Brain.png

Cerebrospinal Fluid (CSF)

  • This is a fluid within the ventricles and subarachnoid space around the brain and spinal cord
    • Composition similar to blood but less protein and different ionic composition

      The circulation of CSF. From Moore & Dalley.
  • Functions
    • Provides nutrition
    • Key in protecting the brain against damage
    • Maintains buoyancy
    • Blood Brain Barrier
  • Secreted by choroid plexuses
    • Transferred back into venous blood via arachnoid granulations
Circulation of CSF
  • CSF is constantly secretedcirculating and reabsorbed in ventricles
Diagram showing the circulation of CSF (light blue = within subarachnoid space, dark blue = within venous sinuses)
  1. Secreted by choroid plexuses
    • One set in each ventricle
  2. Lateral ventricles => 3rd ventricle (via interventricular foramen)
  3. 3rd => 4th ventricle (via Aqueduct of Sylvius)
  4. 4th ventricle => subarachnoid space via medial and lateral apertures
    • Spreads around the spinal cord and cerebellum within the subarachnoid space
  5. Majority then enters Subarachnoid cisterns
    • These are expanded areas which contain most of the CSF
    • Distribute CSF around cerebrum
  6. Reabsorbed by arachnoid granulations
    • These structures communicate the subarachnoid space to venous sinuses in dura
      • Particularly into sagittal venous sinus
  • NB foramina and cerebral aqueduct are easily blocked
    • => Hydrocephalus
  • CSF can be sampled via lumbar puncture
    • Needle into the subarachnoid space in the spine

 

Leave a Reply

Your email address will not be published. Required fields are marked *