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cerebrospinal fluid

Function: - 70% secreted by choroid plexus, 30% from brain parenchyma. - CSF is absorbed into the systemic circulation through the arachnoid villi - >80% of the protein in CSF originates from plasma, the remainder from intrathecal synthesis - pulsatility of the brain's arteries creates a convective force that draws CSF into the brain from the space around its arterial walls & back out again along its veins, facilitating penetration of CSF into the brain parenchyma [5] - CSF exchanges with brain parenchymal interstitial fluid, percolating through & around astroglial end-feet toward nearby veins, along which it then exits the brain thus taking with it neuronal waste products [4] - the veins must propel CSF toward the arachnoid villi where it is absorbed into the systemic circulation - the process is termed glymphatic clearance [5] - waste products such as beta-amyloid & other aggregation-prone proteins are cleared not only alongside veins but also across the blood-brain barrier into the systemic circulation Structure: * image [] Pathology: - pulsatility of the small penetrating arteries in the brain declines with age [5] - reduction of CSF influx into brain parenchyma with age Comparative biology: - distribution of the aquaporin receptor changes with age in mice [4] - normally, aquaporin receptors are located on astrocytic end-feet facing the arteries, where they facilitate uptake of fluid from the peri-arterial space & drive glymphatic flow toward nearby veins - with age, aquaporin receptors redistribute more uniformly facilitating fluid retention within astrocytes more than directing flow from arteries to veins [5] Laboratory: CSF protein electrophoresis (after concentration) 1) ultrafiltrate of plasma 2) all proteins visible on electrophoresis are <150 kD 3) prominent prealbumin band 4) 2 transferrin bands a) beta-1 transferrin b) beta-2 transferrin 5) used largely to detect intrathecal production of IgG -> IgG/albumin ratio < 0.27 considered normal , Total volume (adult): 150 mL (100-160 mL [3]) CSF: production: 0.35 mL/min, 500 mL/day , Also see CSF analysis

Related

cerebrospinal fluid (CSF) protein electrophoresis cerebrospinal fluid analysis intracranial pressure (ICP) liver kidney microsomal 1 Ab in CSF lumbar spinal puncture (LP, Quincke puncture, spinal tap, rachicentesis, rachiocentesis) reference values for CSF constituents

General

extracellular compartment (extracellular space) body fluid

References

  1. Fundamentals of Clinical Chemistry 3rd ed., N.W. Teitz ed., W.B. Saunders, 1988, pg 339
  2. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 1065-67
  3. Tietz Textbook of Clinical Chemistry, 2nd ed. Burtis CA & Ashwood ER (eds), WB Saunders Co, Philadelphia PA, 1993
  4. Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996
  5. Glymphatic Flow, Sleep, microRNA Are Frontiers in Alzheimer's Research. Zilkha Symposium on Alzheimer's Disease and Related Disorders May 6, 2014 http://www.alzforum.org/news/conference-coverage/glymphatic-flow-sleep-microrna-are-frontiers-alzheimers-research
  6. Spector R, Robert Snodgrass S, Johanson CE. A balanced view of the cerebrospinal fluid composition and functions: Focus on adult humans. Exp Neurol. 2015 Nov;273:57-68. Review. PMID: 26247808 Free Article
  7. lumen Anatomy & Physiology. Module 12. The Nervous System Circulation and Protection of the CNS The Ventricular System Dural Sinuses and Veins https://courses.lumenlearning.com/austincc-ap1/chapter/circulation-and-the-central-nervous-system/#m46719-fig-ch13_03_04