Editing Coagulation (section)

===Vasoconstriction===
{{main|Vasoconstriction}}
When there is an injury to a blood vessel, the endothelial cells can release various vasoconstrictor substances, such as endothelin<ref>{{Cite journal |last=Loscalzo |first=J. |date=1995 |title=Endothelial injury, vasoconstriction, and its prevention |journal=Texas Heart Institute Journal |volume=22 |issue=2 |pages=180–84 |pmc=325239 |pmid=7647603}}</ref> and thromboxane,<ref>{{Cite journal |last=Yau |first=Jonathan W. |last2=Teoh |first2=Hwee |last3=Verma |first3=Subodh |date=2015-10-19 |title=Endothelial cell control of thrombosis |journal=BMC Cardiovascular Disorders |volume=15 |page=130 |doi=10.1186/s12872-015-0124-z |issn=1471-2261 |pmc=4617895 |pmid=26481314 |doi-access=free}}</ref> to induce the constriction of the smooth muscles in the vessel wall. This helps reduce blood flow to the site of injury and limits bleeding.