Inhibitors of Blood Clotting; Lysis of Clotting Flashcards
What is the role of antithrombin in blood clotting inhibition?
Antithrombin inactivates thrombin and other proteases involved in blood clotting, such as factor Xa.
Which enzyme does heparin primarily enhance to inhibit clotting?
Heparin enhances the activity of antithrombin.
How does warfarin act as an anticoagulant?
Warfarin inhibits vitamin K epoxide reductase, reducing the synthesis of vitamin K-dependent clotting factors.
Name the protein that inhibits factor Xa and thrombin.
Antithrombin.
What is the mechanism of action of direct thrombin inhibitors?
Direct thrombin inhibitors bind to thrombin and prevent it from converting fibrinogen to fibrin.
Which natural anticoagulant is activated by thrombomodulin-bound thrombin?
Protein C.
What is the role of protein C in blood clotting?
Protein C, once activated, degrades factors Va and VIIIa, reducing thrombin formation.
How does activated protein C (APC) exert its anticoagulant effects?
APC, with its cofactor protein S, inactivates factors Va and VIIIa, inhibiting the clotting cascade.
What is the function of plasmin in clot lysis?
Plasmin degrades fibrin clots into soluble fibrin degradation products.
Which molecule converts plasminogen to plasmin?
Tissue plasminogen activator (tPA).
Name a commonly used fibrinolytic drug.
Alteplase.
How does tissue plasminogen activator (tPA) work in clot lysis?
tPA binds to fibrin in the clot and converts entrapped plasminogen to plasmin, leading to clot breakdown.
What is the primary function of alpha-2 antiplasmin?
Alpha-2 antiplasmin inactivates plasmin to prevent excessive fibrinolysis.
Which enzyme degrades fibrinogen and fibrin into fibrin degradation products?
Plasmin.
How does the urokinase plasminogen activator (uPA) contribute to fibrinolysis?
uPA converts plasminogen to plasmin, aiding in the breakdown of blood clots.
What is the role of factor XIII in the stabilization of blood clots?
Factor XIII cross-links fibrin strands, stabilizing the blood clot.
How does streptokinase promote clot lysis?
Streptokinase activates plasminogen to plasmin, promoting clot lysis.
Which anticoagulant is monitored using the International Normalized Ratio (INR)?
Warfarin.
What is the function of protein S in the regulation of blood clotting?
Protein S acts as a cofactor for activated protein C, enhancing its anticoagulant effects.
How do low molecular weight heparins (LMWH) differ from unfractionated heparin in their action?
LMWH primarily inhibits factor Xa and has a more predictable anticoagulant effect compared to unfractionated heparin.
What is the mechanism of action of factor Xa inhibitors?
Factor Xa inhibitors block the activity of factor Xa, preventing thrombin formation.
Which condition is treated with thrombolytic therapy?
Acute myocardial infarction, ischemic stroke, or pulmonary embolism.
How does antithrombin deficiency affect coagulation?
Antithrombin deficiency leads to an increased risk of thrombosis due to insufficient inhibition of clotting factors.
What is the role of thrombomodulin in anticoagulation?
Thrombomodulin binds thrombin, reducing its clotting ability and promoting the activation of protein C.
