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Clot retraction and fibrinolysis
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Primary hemostasis involves the formation of a platelet plug at the site of an injured blood vessel, and secondary hemostasis involves the coagulation cascade which is where a protein net called a fibrin mesh forms over the platelet plug to reinforce it - forming a blood clot.
Now, anticoagulation occurs during primary and secondary hemostasis and helps regulate clot formation, whereas clot retraction and fibrinolysis occur after primary and secondary hemostasis are complete, and help a clot contract and degrade.
Anticoagulation prevents clots from growing too large and blocking blood flow to tissues supplied by the vessel.
It also prevents clots from getting so big that small parts of the growing clot break off in the form of emboli.
Now, the most important point of clot regulation is when a coagulation factor called thrombin is produced.
Thrombin, or factor II, is a very important clotting factor, because it has multiple pro-coagulative functions. Think of thrombin as the accelerator on a car--the pedal that takes secondary hemostasis from 20 miles per hour to 100 miles per hour!
First, thrombin binds to receptors on platelets causing them to activate.
After an injury to a blood vessel, primary and secondary hemostasis forms a blood clot to stop bleeding. After hemostasis, it follows another process called clot retraction, which stabilizes the clot by pulling together the wounded edges of the vessel. Next, fibrinolysis occurs, which is an enzymatic process during which blood clots are dissolved to clear the way for blood circulation.
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