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26 Cards in this Set
- Front
- Back
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What factors are involved in the extrinsic coagulation pathway?
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Tissue factor converts VII to active form. Coverts X to active form.
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What factors are involved in the intrinsic coagulation pathway?
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Exposed collagen converts XII to active form, converts XI to active form, coverts IX to active form. Thrombin converts VIII to active form. VIII and IX convert X to active form.
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What factors are involved in the common coagulation pathway?
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X converted to active form. With V, converts II, converts fibrinogen to fibrin, which aggregates into a mesh with XIII.
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What is the vessel's response to injury?
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Vasoconstriction
Primary hemostasis (platelet plug) Secondary hemostasis (fibrin clot) Fibrinolysis |
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What are the actions of thrombin? What are the modulators?
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Cleaves fibrinogen
Platelet aggregation Activates XIII, VIII, and V Activates contact factor Activates protein C Modulated by antithrombin III and thrombomodulin. |
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How is the platelet plug formed upon tissue injury?
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vWF binds to exposed collagen, which then binds to GpI on platelets. Platelets release calcium and ADP. ADP induces GpIIb/IIIa expression, which binds to fibronigen on other platelets.
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What are the three deficiencies associated with platelet binding? What are the mutations?
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von Willebrand disease- deficiency in vWF
Bernard-Soulier syndrome- deficiency in GpIb Glanzmann thrombasthenia- GpIIb-IIIa |
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How are factor VIII and vWF related?
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Factor VIII is carried on vWF. When vWF binds to exposed collagen, VIII is released to join the coagulation cascade.
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How is the extrinsic pathway initiated?
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When blood is exposed to non-vascular tissue factor in the sub-endothelial space. TF binds to VII.
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How is the intrinsic pathway initiated?
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Intravascular contact activation with thrombogenic surface.
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What are regulators of the coagulation pathway?
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Antithrombin III blocks thrombin
Protein C and S block factor VIII and V Tissue factor pathway inhibitor blocks factor VII Fibrinolysis |
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What molecules are anticoagulants?
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antithrombin III
thrombomodulin Protein C, S Tissue factor pathway inhibitor Fibrinolysis PGI2 and NO Intact endothelium |
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What molecules are procoagulant?
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Tissue factor
Thrombin APC resistance vWF |
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How does the endothelial cell inhibit coagulation?
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Heparan sulfate
Prostacyclin and NO Thrombomoculin TFPI tPA |
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What are facilitators of fibrinolysis?
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Tissue plasminogen activator (tPA)
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What are inhibitors of fibrinolysis?
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Plasminogen activator inhibitor (blocks tPA degradation of plasminogen to plasmin)
alpha2 plasmin inhibitor (blocks plasmin degradation of fibrin) |
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What is the process of fibrinolysis?
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Plasminogen converted to plasmin by tPA.
Plasmin breaks down fibrin to monomers, then degraded into D-dimers. |
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What is tested by prothrombin time?
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Extrinsic pathway- factor VII deficiency; liver function; Warfarin function, Vitamin K deficiency
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What is tested by partial thromboplastin time?
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Intrinsic pathway- factors VIII, IX, XI; von Willebrand disease, Heparin function
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How is the INR developed? What is it used for?
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Aids in the monitoring of patients taking anticoagulants.
INR= (PT patient/ mean PT normals) ^ ISI (ISI- international sensitivity index) |
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What diseases could be causing abnormal PT and aPTT?
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Anticoagulant
Liver disease Vitamin K deficiency Factors II, V, X deficiency DIC Fibrinolysis Hypofibrinogenemia |
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What are mixing studies? What do they detect?
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Used to distinguish deficiency from inhibitor.
Patient's serum is mixed with normal plasma. In a deficiency, the abnormal test should be corrected with the mixing. In an inhibitor, the abnormal test will not be corrected with mixing test. |
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What special tests are done for Von Willebrand disease?
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VIII clotting activity
VIII antigen quantitative measure vWF antigen measurement vWF ristocetin cofactor activity Molecular testing |
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What would be the causes of abnormal bleeding time?
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vWF
Thrombocytopenia DIC Fibrinolysis Aspirin |
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What are the results of DIC?
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Consumption of platelets, fibrinogen, factors II, V, VIII, and depletion of antithrombin II.
Results in secondary fibrinolysis and anticoagulation |
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Which factors are dependent on vitamin K? Where does the processing occur?
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Factors II, VII, IX and X; protein C and S.
Carboxylation of the factors in the liver depend on vitamin K. |
