coagulation 2
Terms
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- What is found in the alpha granules of platelets?
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Fibrinogen
Fibrinectin
VWF
Thrombospondin
Vitronectin - What is found in the dense bodies?
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ADP
ATP
5HT
Ca - Steps of primary hemostasis
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Injured BV has exposed collagen
VWF binds collagen
GPIb of platelet binds to VWF, causing conformational change in IIb/IIIA
IIb/IIIA is now able to bind fibrinogen
Platelets express receptors for factors V and VIII; extend pseudopods - What role does TXA2 play in coagulation and how does it work?
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TXA2 causes platelet aggregation and vasocontriction.
It decreases the level of cAMP, which causes an increase in Ca, which promotes platelet aggregation. - How does PGI2 work in coagulation? Where does it come from?
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Opposes the action of TXA2 by increasing the levels of cAMP, which decreases the levels of Ca. This inhibits platelet aggregation.
It is released by vascular endothelial cells. - What role does ADP play in coagulation?
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Causes platelets to swell and adhere to each other. It then caauses them to release TXA2 and more ADP in a positive feedback mechanism.
The clot formed is large enough to fill the injured area. - What is the tenase reaction?
- The reaction that causes the formation of Xa (IXa + VIIIa + X) -> Xa
- What does factor XIII do?
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Provides clot strength and normal wound healing.
Without it, clots dissolve more quickly - What does ATIII bind to?
- Heparan sulfate
- What does AT III inactivate?
- IX, X, XI, II
- What do proteins C and S inactivate?
- Va, VIIIa
- What does TFPI do?
- Inactivates VIIa-TF complexes
- What does heparin do?
- Enhances the activity of ATIII (inactivates Ix, X, XI, II)
- What does warfarin do?
- Binds vitamin K, so II, VII, X, XI, protein C and S are all inhibited
- What does thrombomodulin do?
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Causes the activation of protein C
Also inactivates all the other serine proteases in coagulation - What does tPA do?
- Converts plasmingen to plasmin, which then breaks up the clot and releases FSP (D-dimer)
- What does urokinase do?
- converts plasminogen -> plasmin, forms FSP (d-dimer)
- What releases tPA and urokinase?
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Endothelium
Fibrin - What does PAI-I do?
- down-regulates plasmin
- What is alpha-2-anti-plasmin?
- Inhibits fibrinolysis, by collecting free plasmin `
- IL-11
- Allows for increasing the number of circulating platelets
- C-MPL
- TPO receptor on platelets
- Treatments for VWD
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DDAVP
Intermdiate Purity Factor - What is Intermediate Purity Factor
- Combination of VWF and factor VIII; used to treat VWD