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26 Cards in this Set
- Front
- Back
What is consolidation?
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The retraction of the hemostatic plug by active shortening of platelet contractile filaments.
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What enzyme is responsible for fibrinolysis?
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Plasmin, a protease formed from the proenzyme plasminogen
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What is the role of Factor XIIIa and how is it activated?
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Factor XIIIa is responsible for the formation of covalent crosslinks in fibrin; it is activated by thrombin.
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What are the substrates for platelet adhesion?
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Collagen and Von willebrand Factor (VWF).
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What substances does the endothelium release to inhibit clot formation?
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Prostacyclin (PGI2) and NO2.
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Where is tissue factor found?
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Tissue factor (TF) is found on most non-vascular cells and can be found on endothelial cells after being activated.
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How is thrombin generated initially?
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By a complex of Factor Xa and Factor V on the membrane of tissue factor-bearing cells. Complex formation markedly accelerates the rxn.
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How does ADP affect coagulation?
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ADP is an activator
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How do platelets aggregate?
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By means of fibrinogen molecules binding to fibrinogen receptors which are exposed only on activated platelets.
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what is the role of the TFPI-Xa complex?
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It inhibits VIIa, which increases the importance of the intrinsic pathway as thrombin generation proceeds.
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What is the role of the VIIa-TF complex?
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It is the main activator of Factor IX and Factor X.
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What is meant by the thrombin burst?
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The cascade happens faster on the platelet surface faster than anywhere else.
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What deficiency causes classic Hemophilia?
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Factor VIII
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Which factor is not required for hemostasis?
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Factor XII
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How is blood anticoagulated for PT or APTT?
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by chelating Calcium with citrate
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Which factors are Vitamin K dependent?
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V, VII, IX, X
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What is Vitamin K's role?
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It catalyzes the addition of an extra carboxyl group to certain glutamic acid residues in each of the vitamin K-dependent factors, converting them to gamma-carboxyglutamic acid.
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Where in the coagulation cascade does Warfarin act?
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Warfarin inhibits the conversion of glutamic residues on the vitamin K dependent factors to gamma-carboxyglutamic acid.
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How is a PT done?
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Add the reagent tissue factor and Ca and time the process
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How is APTT done?
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Add the activator and phospholipid and incubate. Then ad Ca later.
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What is the difference between PT and APTT?
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PT only mesures the integrity of the extrinsic pathway while the APTT measures the integrity of both extrinsic and intrinsic.
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What is the most important inhibitor of thrombin activity?
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Antithrombin
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What is heparin's relationship to anithrombin?
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The rate of thrombin inhibition is much enhanced when antithrombin binds to certain negatively charged polysaccharides including warfarin.
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What is the role of Thrombomodulin and Modulin (complex)?
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together they activate the proenzyme Protein C
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What is the role of Protein Ca?
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Protein Ca catalyzes the proteolytic inactivation of Factors V and VIII when complexed with Protein S.
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What is the most common of the "thrombophilias?"
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Activated Protein C (APC) resistance is the most common
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