Editing Coagulation (section)

{{Short description|Process of formation of blood clots}}
{{About|blood clotting}}
{{Use dmy dates|date=July 2019}}
{{Infobox body process
|name              = Coagulation
|image  = File:Coagulation in vivo.png|right|thumb|
|image_size        = 400 px|
|caption           = Blood coagulation pathways ''in vivo'' showing the central role played by [[thrombin]]
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|health            = Beneficial
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'''Coagulation''', also known as '''clotting''', is the process by which [[blood]] changes from a [[liquid]] to a [[gel]], forming a [[thrombus|blood clot]]. It results in [[hemostasis]], the cessation of blood loss from a damaged vessel, followed by repair. The process of coagulation involves [[Platelet-activating factor|activation]], [[Cell adhesion|adhesion]] and aggregation of [[platelet]]s, as well as deposition and maturation of [[fibrin]].

Coagulation begins almost instantly after an injury to the [[endothelium]] that lines a [[blood vessel]]. Exposure of blood to the subendothelial space initiates two processes: changes in platelets, and the exposure of subendothelial [[Tissue factor|platelet tissue factor]] to [[coagulation factor VII]], which ultimately leads to cross-linked [[fibrin]] formation. Platelets immediately form a plug at the site of injury; this is called ''primary hemostasis. Secondary hemostasis'' occurs simultaneously: additional coagulation factors beyond factor VII ([[#Coagulation factors|listed below]]) respond in a cascade to form fibrin strands, which strengthen the [[platelet plug]].<ref name="Furie">{{Cite journal |last=Furie |first=Barbara C. |last2=Furie |first2=Bruce |date=December 2005 |title=Thrombus formation in vivo |journal=The Journal of Clinical Investigation |volume=115 |issue=12 |pages=3355–62 |doi=10.1172/JCI26987 |pmc=1297262 |pmid=16322780}}</ref>

Coagulation is highly [[Conserved sequence|conserved]] throughout biology. In all [[mammal]]s, coagulation involves both cellular components (platelets) and [[protein]]aceous components (coagulation or clotting factors).<ref name="Michelson2006">{{Cite book |title=Platelets |date=2007 |isbn=978-0-12-369367-9 |doi=10.1016/B978-0-12-369367-9.X5760-7}}{{pn|date=September 2024}}</ref><ref name="medline2024">{{Cite web |title=Coagulation Factor Tests |url=https://medlineplus.gov/lab-tests/coagulation-factor-tests/ |access-date=27 April 2024 |website=MedlinePlus Medical Test |language=en}}</ref> The pathway in humans has been the most extensively researched and is the best understood.<ref>{{Cite book |last=Schmaier |first=Alvin H. |title=Concise guide to hematology |last2=Lazarus |first2=Hillard M. |publisher=Wiley-Blackwell |year=2011 |isbn=978-1-4051-9666-6 |location=Chichester, West Sussex, UK |page=91 |oclc=779160978}}</ref> Disorders of coagulation can result in problems with [[Bleeding|hemorrhage]], [[Bruise|bruising]], or [[thrombosis]].<ref name="isbn1-4051-8460-4">{{Cite book |last=Lillicrap |first=D. |url=https://archive.org/details/practicalhemosta00keyn |title=Practical Hemostasis and Thrombosis |last2=Key |first2=Nigel |last3=Makris |first3=Michael |last4=Denise |first4=O'Shaughnessy |publisher=Wiley-Blackwell |year=2009 |isbn=978-1-4051-8460-1 |pages=1–5 |url-access=limited}}</ref>