Editing Cerebrospinal fluid (section)

===Function===
CSF serves several purposes:

#'''Buoyancy:''' The actual [[mass]] of the [[human brain]] is about 1400–1500 grams, but its net [[weight]] suspended in CSF is equivalent to a mass of 25–50 g.<ref>{{cite book |title= The Human Nervous System |last1 = Noback |first1 = Charles | first2 = Norman L. | last2 = Strominger | first3 = Robert J. | last3 = Demarest | first4 = David A. | last4 = Ruggiero | name-list-style = vanc |year= 2005 |publisher= Humana Press  |isbn= 978-1-58829-040-3 |page= 93}}</ref><ref name="WRIGHT2012">{{cite journal | vauthors = Wright BL, Lai JT, Sinclair AJ | title = Cerebrospinal fluid and lumbar puncture: a practical review | journal = Journal of Neurology | volume = 259 | issue = 8 | pages = 1530–45 | date = August 2012 | pmid = 22278331 | doi = 10.1007/s00415-012-6413-x | s2cid = 2563483 }}</ref> The brain therefore exists in [[neutral buoyancy]], which allows the brain to maintain its [[density]] without being impaired by its own weight, which would cut off blood supply and kill [[neuron]]s in the lower sections without CSF.<ref name=SALADIN2012 />
#'''Protection:''' CSF protects the brain tissue from injury when jolted or hit, by providing a fluid buffer that acts as a [[shock absorber]] from some forms of mechanical injury.<ref name=WRIGHT2012 /><ref name=SALADIN2012 />
#'''Prevention of brain ischemia:''' The prevention of [[brain ischemia]] is aided by decreasing the amount of CSF in the limited space inside the skull. This decreases total [[intracranial pressure]] and facilitates blood [[perfusion]].<ref name="WRIGHT2012" />
#'''Regulation:''' CSF allows for the [[Homeostasis|homeostatic regulation]] of the distribution of substances between cells of the brain,<ref name="SAKKA2011"/>  and [[neuroendocrine]] factors, to which slight changes can cause problems or damage to the nervous system. For example, high [[glycine]] [[concentration]] disrupts [[temperature]] and [[blood pressure]] control, and high CSF [[pH]] causes [[dizziness]] and [[Syncope (medicine)|fainting]].<ref name="SALADIN2012" />
#'''Clearing waste:''' CSF allows for the removal of waste products from the brain,<ref name=WRIGHT2012 /> and is critical in the brain's [[lymphatic system]], called the [[glymphatic system]].<ref name=Iliff>{{cite journal | vauthors = Iliff JJ, Wang M, Liao Y, Plogg BA, Peng W, Gundersen GA, Benveniste H, Vates GE, Deane R, Goldman SA, Nagelhus EA, Nedergaard M | display-authors = 6 | title = A paravascular pathway facilitates CSF flow through the brain parenchyma and the clearance of interstitial solutes, including amyloid β | journal = Science Translational Medicine | volume = 4 | issue = 147 | pages = 147ra111 | date = August 2012 | pmid = 22896675 | pmc = 3551275 | doi = 10.1126/scitranslmed.3003748 }}</ref> Metabolic waste products [[diffusion|diffuse]] rapidly into CSF and are removed into the bloodstream as CSF is absorbed.<ref>{{Cite book |last1=Ropper |first1=Allan H. |title=Adams and Victor's principles of neurology |last2=Adams |first2=Raymond D. |last3=Victor |first3=Maurice |last4=Brown |first4=Robert H. |date=2005 |publisher=McGraw-Hill Medical Pub. Division |isbn=978-0-07-141620-7 |edition=8 |location=New York |pages=530 |chapter=Chapter 30 |oclc=61409790}}</ref>  When this goes awry, CSF can become toxic, such as in [[amyotrophic lateral sclerosis]], the most common form of [[motor neuron disease]].<ref>{{Cite journal| vauthors = Kwong KC, Gregory JM, Pal S, Chandran S, Mehta AR |title=Cerebrospinal fluid cytotoxicity in amyotrophic lateral sclerosis: a systematic review of in vitro studies|url= |journal=Brain Communications|year=2020|volume=2|issue=2|pages=fcaa121|language=en|doi=10.1093/braincomms/fcaa121|pmid=33094283|pmc=7566327|doi-access=free}}</ref><ref>{{cite journal | vauthors = Ng Kee Kwong KC, Mehta AR, Nedergaard M, Chandran S | title = Defining novel functions for cerebrospinal fluid in ALS pathophysiology | journal = Acta Neuropathologica Communications | volume = 8 | issue = 1 | pages = 140 | date = August 2020 | pmid = 32819425 | pmc = 7439665 | doi = 10.1186/s40478-020-01018-0 | doi-access = free }}</ref>