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27 Cards in this Set
- Front
- Back
define primary, secondary, and tertiary hemostasis
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Primary hemostasis: This is defined as the formation of the platelet plug.
Secondary hemostasis: This is defined as the formation of fibrin through the coagulation cascade. Tertiary hemostasis: This is defined as the formation of plasmin for breakdown of the clot |
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what granules in the platelet play a role in forming a hemostatic plug?
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Alpha
Hemostatic Proteins: fib, FV, vWf, PAI-1(inhibits fibrinolysis) & plasminogen (fibinolysis) |
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what is platelet adhesion?
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Attachment of platelets to something besides other platelets
Binding of plts to subendothelial collagen via plt GP Ib and vWf forming a bridge |
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Adhesion triggers morphologic & functional changes known as ...?
what does this do? |
Activation
Changes in: Metabolic biochemistry Generation of thromboxane A2 and 2nd messangers Platelet shape change Disc shape to spheres with psuedopod via actin/myosin |
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in primary hemostais, what is responsible for surface receptor exposure? what is this required for?
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Activation
Required for plt binding to fibrinogen |
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what is aggregation? what is need for this to occur? (2)
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Aggregation is the attachment of platelets to one another.
Fibrinogen and Calcium are needed for aggregation to occur |
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what is secretion?
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after aggregation the plts discharge granule contents into the surrounding area stimulating other plts.
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what is Template Bleeding Time?
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Standardized incision made on forearm, length of time for bleeding to stop measured.
1 to 9 minutes normal A defect in platelet function will cause prolongation |
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When do you do a platelet aggregation study?
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Tests ability of platelets to aggregate with various agonist
Indicated with normal platelet count, but prolonged bleeding; (History & Physical) |
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what test can discriminate between inherited platelet disorders (vWD, Glanzmann’s) and acquired drug related disorders (ASA)?
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Platelet function Analyzer
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Defined as the formation of fibrin through the coagulation cascade =
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secondary hemostasis
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what is the extrinsic secondary pathway?
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Extrinsic: involves tissue factor and FVII, which activates FX
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what is the intrinsic secondary pathway?
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Intrinsic: cofactors, Ca plus phospholipid mediating activation of FX
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what is the common secondary pathway?
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the extrinsic. and intrinsic paths converge at aFX which mediates fibrin formation
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what is the main pathway for for initiation of secondary hemostasis? which is used to amplify?
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extrinsic pathway
the intrinsic is used to amplify the effect |
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what initiates the extrinsic pathway of hemostasis?
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Exposure of Tissue Factor, expressed by endothelial cells, subendothelial connective tissue & monocytes.
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what activates the intrinsic pathway?
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Thrombin generated from extrinsic path. Activates FXI & VIII directly
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what activates protein C and S? What do they do?
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Interestingly, thrombin activates them.
Activation of C and S then downregulates to coagulation pathway thus thrombin both activates and inactivates these pathways |
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what are the vitamin K dependent factors?
**TEST |
Requires vitamin K for synthesis; needs Ca & phospholipid. (known as Vitamin K dependent factors)
II VII IX X 1972 |
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why is Vitamin K so important?
***TEST |
Provides critical Ca receptor essential for binding the pro-coagulant factor to phospholipid
In absence of Vit K, factors (1972) still synthesized in liver, found in plasma, but are nonfunctional, so YOU CANNOT CLOT |
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what screens for intrinsic and common pathway problems?
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Activated Coagulation Time
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What does a prolongation of PT mean?
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defect in Extrinsic or Common pathways
Sensitive monitor of Vit K dependent FVII. |
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So PT measures what?
and aPTT? |
PT: Extrinsic/Common
aPTTT: Intrinsic/Common |
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PT is a good monitor for what therapy
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comadin
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aPTT is good to monitor what therapy?
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heparin
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What is the thrombin time? what does it allow you to detect?
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Measures only conversion of fibrinogen to fibrin
can show: Deficiency in fibrinogen Dysfibrinogenemia Presence of inhibitors such as heparin, FDPs |
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SUMMARY SLIDE
Thrombin time Common pathway Monitor for presence of heparin aPartial thrombopastin time Intrinsic pathway; common pathway Monitor heparin therapy Prothrombin time Extrinsic pathway; common pathway Monitor coumadin therapy |
That is the Take home slide
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