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Cerebrospinal fluid(csf)

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Cerebrospinal fluid(csf)

  1. 1. Cerebrospinal Fluid(CSF)<br />Saddam Ansari<br />Tbilisi State Medical University<br />
  2. 2. Introduction<br />CSF is clear, colorless and transparent<br />Circulates through cavity of the:<br />Brain<br />Subarachnoid space<br />Central canal of spinal cord<br />Part of Extracellular fluid (ECF)<br />
  3. 3. Properties <br />Volume : approximately 150 mL<br />Rate of formation: approximately 0.3 mL/min<br />Specific gravity : 1.005<br />Reaction : Alkaline<br />
  4. 4. Composition<br />
  5. 5. Continued…<br />As CSF is part of ECF therefore it contain more amount of Sodium than Potassium.<br />Contains some lymphocytes.<br />CSF secreted by ventricles does not contain any cell.<br />The lymphocytes are added when it flows in the spinal cord.<br />
  6. 6. Formation of CSF<br />Site of formation<br />Formed by the choroid plexus situated within the ventricles.<br />The choroid plexus are tuft of capillary projections present inside ventricles and covered by:<br />Pia mater <br />Ependymal covering.<br />
  7. 7. Continued...<br />Mechanism of formation<br />Formed by process of secretion.<br />Does not involve ultrafiltration or dialysis.<br />Uses energy.<br />Active transport mechanism is involved in secretion.<br />
  8. 8. Continued…<br />Substances affecting the formation of CSF<br />Pilocarpine, ether and extracts of pituitary gland stimulates the secretion of CSF by stimulating choroid plexus.<br />Injection of isotonic saline also stimulates CSF formation.<br />
  9. 9. Continued…<br />Injection of hypotonic saline<br />Causes greater rise in capillary pressure and intracranial pressure,<br />Fall in osmotic pressure leading to increase in CSF formation.<br />Hypertonic saline <br />Decreases CSF formation <br />Decreases CSF pressure<br />
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  12. 12. Absorption of CSF<br />Mostly absorbed by the Arachnoid villi into Dural sinuses and Spinal veins.<br />Small amount is absorbed along the perineural spaces into cervical lymphatics and in to the perivascular spaces.<br />Normally, 500 mL of CSF is formed everyday and equal amount is absorbed.<br />
  13. 13. Mechanism of absorption of CSF<br />By filtration due to pressure gradient between hydrostatic pressure in the subarachnoid space fluid<br />And the pressure that exists in the Dural sinus blood.<br />The colloidal substances pass slowly and crystalloids are absorbed rapidly.<br />
  14. 14. Pressure exerted by CSF<br />Varies in different position:<br /> Lateral recumbent position = 10-18 cm of H2O<br /> Lying position = 13 cm of H2O<br /> Sitting position = 30 cm of H2O<br /> Coughing and crying increases the pressure by decreasing the absorption.<br /> Compression of internal jugular vein also raises the CSF pressure.<br />
  15. 15. Function of CSF<br />Protective Function:<br />Acts as buffer <br />Protects the brain from shock<br />If brain receives severe blow , countercoup injury may take place.<br />
  16. 16. Continued…<br />Regulation of Cranial Content Volume<br />Is very essential because<br />When substances are absorbed into the venous sinuses, intracranial pressure is raised,<br />Intracranial pressure in turn interferes with the cerebral circulation causing Asphyxia.<br />It is prevented by greater absorption of CSF to give space for increasing cranial contents.<br />
  17. 17. Continued…<br />Medium of Exchange<br />CSF is the medium through which substances like :<br />Nutritive substances<br />Waste materials<br /> are exchanged between blood and brain tissues.<br />
  18. 18. Collection of CSF<br />Collected by :<br />Cisternal puncture or <br />Lumbar puncture<br />In Cisternal puncture <br />CSF is collected by passing needle between Occipital bone and Atlas, so it enters the cisterna magna.<br />
  19. 19. Continued…<br />In Lumbar puncture<br />The Lumbar puncture needle is introduced into the subarachnoid space in the Lumbar region , between the third and fourth Lumbar spines. <br />Uses of Lumbar puncture <br />Collecting CSF for diagnostic purpose.<br />Injecting drugs for spinal anesthesia, analgesia and chemotherapy.<br />Measuring pressure exerted by CSF.<br />
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  21. 21. Blood–Cerebrospinal Fluid Barrier<br />Barrier between the blood and cerebrospinal fluid .<br />Exists at the Choroid plexus.<br />Similar to Blood-Brain Barrier(BBB)<br />Allows the movement of only those substances, which are allowed by BBB.<br />
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  23. 23. Substances which can pass through Blood-Cerebrospinal Fluid Barrier<br />Oxygen<br />Carbon dioxide<br />Water <br />Glucose <br />Amino acids<br />Electrolytes <br />Drugs such as L-dopa, 5-hydroxytryptamine sulfonamides, tetracycline and other lipid soluble drugs<br />
  24. 24. Continued…<br />Anesthetic gases such as ether, nitrous oxide which are lipid soluble<br />Other lipid soluble substances.<br />
  25. 25. Substances which can’t pass through Blood-Cerebrospinal Fluid Barrier<br />Injurious chemical agents.<br />Pathogens such as bacteria.<br />Drugs such as Penicillin and the Catecholamines.<br />Dopamine also can’t pass therefore Parkinsonism is treated with L-dopa instead of dopamine.<br />
  26. 26. Continued…<br />Bile pigments<br />However barrier is not well developed in infants.<br />The bile pigments enter the brain tissues .<br />During jaundice in infants, the bile pigments enter the brain and causes damage of Basal ganglia leading to Kernicterus.<br />
  27. 27. CSF disorders<br />Hydrocephalus<br />Abnormal accumulation of CSF in the skull with enlargement of head.<br />2 types of Hydrocephalus<br /> 1. non-communicating <br /> 2. communicating<br />
  28. 28. Continued…<br />Non-communicating Hydrocephalus or Internal Hydrocephalus<br /> Due to the obstruction of any of the foramen through which CSF escapes results in dilation of ventricular cavity.<br />Communicating Hydrocephalus or External Hydrocephalus<br /> Due to blockage of Arachnoid villi.<br />
  29. 29. Continued…<br />Symptoms of Hydrocephalus:<br />Headache <br /> Vomiting <br /> Atrophy of brain <br /> Mental weakness<br /> Convulsions<br />
  30. 30. Continued…<br />Normal pressure Hydrocephalus<br />Same as Communicating Hydrocephalus but it is due to decreased CSF absorption.<br />Symptoms :<br />Gait instabiltiy<br />Urinary incontinence<br />Dementia<br />
  31. 31. Thank you<br />