Editing Extracellular fluid (section)

== Function ==
[[File:Cell membrane detailed diagram en.svg|thumb|340px|Cell membrane details between extracellular and intracellular fluid]]
[[File:Sodium-potassium pump and diffusion.png|thumb|340px|Sodium–potassium pump and the diffusion between extracellular fluid and intracellular fluid]]
Extracellular fluid provides the medium for the exchange of substances between the ECF and the cells, and this can take place through dissolving, mixing and transporting in the fluid medium.<ref name="GT">{{cite book|last1=Tortora|first1=Gerard|name-list-style=vanc|title=Principles of anatomy and physiology|date=1987|publisher=Harper & Row|location=New York|isbn=978-0-06-046669-5|pages=[https://archive.org/details/principlesofanat05tort/page/61 61]–62|edition=5th ed. Harper international|url=https://archive.org/details/principlesofanat05tort|url-access=registration}}</ref> Substances in the ECF include dissolved gases, nutrients, and [[electrolyte]]s, all needed to maintain life.<ref>{{cite book|last1=Tortora|first1=Gerard|name-list-style=vanc|title=Principles of anatomy and physiology|date=1987|publisher=Harper & Row|location=New York|isbn=978-0-06-046669-5|page=[https://archive.org/details/principlesofanat05tort/page/17 17]|edition=5th ed. Harper international|url=https://archive.org/details/principlesofanat05tort|url-access=registration}}</ref> ECF also contains materials [[Secretion|secreted]] from cells in soluble form, but which quickly coalesce into fibers (e.g. [[collagen]], [[reticular connective tissue|reticular]], and [[elastic fibres]]) or precipitates out into a solid or semisolid form (e.g. [[proteoglycan]]s which form the bulk of [[cartilage]], and the components of [[bone]]). These and many other substances occur, especially in association with various proteoglycans, to form the [[extracellular matrix]], or the "filler" substance, between the cells throughout the body.<ref>{{Cite book|title=Fundamentals of Biochemistry: Life at the Molecular Level|last1=Voet|first1=Donald|last2=Voet|first2=Judith|last3=Pratt|first3=Charlotte | name-list-style = vanc |publisher=John Wiley & Sons|year=2016|isbn=978-1-118-91840-1|location=Hoboken, NJ|pages=235}}</ref> These substances occur in the extracellular space, and are therefore all bathed or soaked in ECF, without being part of it.