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Cerebrospinal fluid (CSF) I


The characteristics & composition of CSF



Appearance Clear & colorless
Volume 130ml
Rate of production 0.5ml/ min (Production of CSF is not pressure regulated, keep on producing even the reabsorption is obstructed)
Pressure (Spinal tap with patient in lateral recumbent position) 60 – 150 mmH2O
Constant, but can increase in:
   Straining
   Laughing     
   Coughing
   Sneezing
   Compressing IJV of the neck)
Composition 
Protein 15 – 45mg/ 100ml
Glucose 50 – 85mg/ 100ml (CSF Glucose </ = 2/3 of blood glucose)
Cl– 720 – 750mg/ 100ml
Number of cells 0 – 3 Lymphocytes/ mm3
Formation Mainly in the choroid plexus & little amount from ependymal cells
Circulation Circulation is aided within the skull by:
     Arterial pulsation of the choroid
     Cilia on the ependymal cells

In the spinal canal, it’s aided by:
     Pulsation of spinal arteries
     Movements of the vertebral column
     Respiration
     Coughing
     Changing of the body position
Absorption The main site is arachnoid granulations (They increase in size & number and tend to become calcified with advancing age)
Absorption                 : CSF pressure > Venous pressure
Prevents reflux of blood when Venous pressure > CSF pressure (Arachnoid villi serves as valves)
Rate of absorption controls the CSF pressure

The functions of CSF

1) Cushions & protects CNS from trauma
2) Provides mechanical floating (Buoyancy) & support to brain
3) Serves as a reservoir & assists in the regulation of the content of the skull
4) Nourishes the CNS
5) Removes metabolites from the CNS
6) Serves as a pathway for pineal secretions to reach the pituitary gland

Blood brain barrier

1) It’s formed by tight junctions between the endothelial cells of the blood capillaries

2) Non lipid soluble or water soluble substances cannot cross the BBB

Drugs which cannot cross the BBB
Drugs which can cross the BBB
  • Penicillin                              : In meningitis can cross through inflamed areas
  • Nor epinephrine              : Mot lipid soluble, but water soluble
  • Phenylbutazone               : Highly protein bound
  • Dopamine
  • Atropine methyl nitrate
  • Chloramphenicol             
  • Tetracycline
  • Sulfonamide
  • Atropine
  • Levodopa
Cerebrospinal fluid (CSF) I Cerebrospinal fluid (CSF) I Reviewed by Radiology Madeeasy on August 04, 2010 Rating: 5
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