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41 Cards in this Set
- Front
- Back
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What is the definition of primary hemostasis?
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PLATELETS
Immediate response to vascular injury Endothelial cells and underlying CT |
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What is secondary hemostasis?
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Blood proteins, procoagulants
Anticoagulants, fibrinolytic agents COAGULATION |
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What is the pathway of primary hemostasis?
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Platelet adhesion via vWF--> platelet shape change --> granule release (ADP, TXA2) --> Recruitment of more platelets --> Aggregation (hemostatic plug)
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What is the prothrombic effect of endothelium?
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Endothelium causes vasoconstriction
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What do a granules contain?
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P-selectin - adhesion molecule
Fibrinogen, fibronectin, factors 5 + 8 Growth factors PDGF, TGF-B |
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What do dense granules contain?
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Products for metabolism/recruitment, ADP, serotonin, epi, calcium
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What happens when platelets degranulate after shape change?
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Release ADP, Ca
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What are the 3 aggregation mediators?
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ADP
TxA2 Thrombin |
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What does thrombin bind to, and what does it cause?
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Thrombin binds to PAR on platelets --> causes more secretion of ADP
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What is the pathology of von Willebrand Disease?
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Deficiency of vWF
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What is the pathology of Bernard-Soulier syndrome?
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Large platelets and small platelet count
Defective primary hemostasis |
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What is Glansmann thrombasthenia?
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Hereditary defect of Gp11b111a, doesn't allow binding of platelets
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What is the mechanism of action of Clopidogrel?
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ADP receptor inhibitor, used to prevent thrombosis
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What is the mechanism of action of Aspirin and NSAIDS?
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Blocks COX action on AA
Prevent production of TxA2 |
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What is thrombocytopenia?
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Decreased platelet numbers from decreased production in marrow or from increased peripheral destruction
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What does prostacyclin do?
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Vasodilation
Inhibits platelet aggregation OPPOSITE OF TXA |
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What is the source of prostacyclin?
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Endothelial cells
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What does thromboxane do?
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Vasoconstriction
Stimulates platelet aggregation |
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What is the source of thromboxane?
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Platelet
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What does nitric oxide do, and what is it's source?
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Vasodilation, inhibits platelet aggregation
Source: endothelial cells |
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What does thrombin do in regards to secondary hemostasis?
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Proteolyzes fibrinogen to fibrin
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What does fibrin do in regards to secondary hemostasis?
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Fibrin polymerizes into insoluble gel that encases platelets to form definitive secondary hemostatic plaque
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What factor number is fibrinogen?
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I
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What factor number is prothrombin?
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II
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What factor number is factor s?
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V
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What 5 factors are vitamin K dependent?
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7, 9, 10, 11, Protein C
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Which intrinsic and extrinsic factors contribute to prothrombin?
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Intrinsic --> factor 12
Extrinsin --> tissue factor + factor 7 |
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What is the intrinsic pathway of factors?
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12 --> 11 --> 9 --> 8
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What is the extrinsic pathway of factors?
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7
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What is the common pathway of factors?
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10 --> 5 --> 2
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What does PT (prothrombin time) measure?
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Time to clot = 12-14"
Monitors coumadin Factor deficiencies of 7, 10, 5, 2 or 1 will show prolonged PT Increases from deficiencies in extrinsic or common |
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What does PTT (partial thromboplastin time) measure?
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Monitors heparin
Time to clot = ~40" Increases from deficiencies in intrinsic or common Factors 12, 11, 9, 8, 10, 5, 2, 1 |
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What are the 2 most common hereditary clotting deficiencies?
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Factor 8 and vWF deficiencies
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What does coumadin/warfarin do?
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Vitamin K antagonist
Common tx for pt's prone to thrombi |
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What are the clinical features of Hemophilia A and B?
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Spontaneous hemorrhage, easy bruising, hemorrhage into joints, prone to CNS hemorrhage
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What lab value is elevated with Hemophila A and B?
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PTT
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What lab values are elevated with DIC?
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PT and PTT
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What lab values are prolonged in Vit K deficiency?
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Acute deficiency - PT prolonged
Chronic deficiency - PTT prolonged |
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What are clinical features of bleeding from defective primary hemostasis?
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Thrombocytopenia, vWF disease, scurvy
Petichiae, ecchymosis, Gums/GI/GU bleeds |
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What are clinical features of bleeding from defective secondary hemostasis?
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Factor deficiency, liver disease, acquired inhibitors
Hematomas, joints, mm, CNS, retroperitoneum |
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What are the anti-thrombic effects of endothelium?
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Intact endothelium resists thrombosis
Physicall inhibits platelet adhesion PTI2, NO, ADPase = vasodilation + platelet aggregation inhibition |
