BC platelet plug #28.txt

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BC platelet plug #28.txt
2011-02-15 19:43:15
BC platelet plug

BC platelet plug #28
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  1. What is hemostasis?
    no bleeding
  2. What are the two parts of a thrombus?
    • platelet plug
    • fibrin clot
  3. What are the three events of a vascular injury?
    • 1) vasoconstriction
    • 2) Platelet plug
    • 3) fibrin clot
  4. What is the difference b/t thrombocytopenia and thrombocytosis?
    • -cytopenia: not enough platelets
    • -cytosis: too many plateles
  5. What are the three granule types in platelets?
    • Dense granules: ADP and Ca
    • Alpha granules: vWF, fibrinogen, serotonin, PDGF
    • Dense tubular system: Ca
  6. What prostanoid is active in healthy individuals and what is its function?
    PGI2: inhibits platelet formation
  7. How does PGI2 function to stop platelet formation?
    • binds Gs = cAMP
    • cAMP activate dense tubular system
    • dense tubular system uptakes Ca
    • Less intracellular Ca = less platelet plug formation
  8. What does shear force to to vWF-collagen binding?
    Increases (happens in people with thrombi or hypertension)
  9. What are the five steps of platelet plug formation?
    • 1) Adhesion
    • 2) Activation
    • 3) degranulation/secretion
    • 4) shape change
    • 5) aggregation
  10. What is the most potent agonist of platelet activation?
  11. What G protein is used for activation?
  12. What is the function of ADP and is it Autocrine or Paracrine?
    • Increase platelet-aggregation
    • Autocrine
  13. What is function of Plavix?
    Inhibit ADP binding to its Autocrine receptor so platelet-aggregation is inhibited
  14. What are the three important protein changes during the Shape Change?
    • 1) GpIIa/IIIb
    • 2) Phosphatidylserine flips out = more negative
    • 3) negativity attracts VIIIa and Va = help with fibrin clot
  15. What does GpIIIa/IIIb bind?
    Fibrinogen that was secreted from Alpha granules
  16. What is the binding site on fibrinogen?
    RGD motif
  17. What is the function of integrilin?
    • Inhibit binding of fibrinogen to GpIIa/IIIb by competing with fibrinogen
    • inhibit platelet aggregation
  18. gWhich COX can recover after usage of low-dose aspirin and why?
    COX-2 due to a nucleus