1. Factor released by platelets to cause vasoconstriction?
    Thromoxin A2
  2. Four mechanisms to hemostasis?
    • 1. vascular constriction
    • 2. platelet plug
    • 3. blood coagulation
    • 4. growth of fibrous tissue
  3. Contactile fibers contained in platelets
    actin, myosin, thombosthenin
  4. Ion stored by platelets?
    Calcium, dence granual
  5. Functions of platelet derived growth factor
    causes vascular smooth muscle, vascular endothelial cells, and fibroblasts to grow and multiply
  6. Molecule on platelet surface that activates clotting (generic)
  7. Half life of platelets and method of distraction
    8-12 days, tissue macrophages, mainly spleen
  8. when platelets bind to the endothelium what causes the release of granolas?
  9. three location of vWF
    platelets, endothelium, circulation
  10. Two secretions of platelets that activate more platelets?
    ADP, thromboxan A2
  11. Loose plug
    platelets only
  12. Responsible for plugging thousands of vascular holes daily?
  13. major functional unit of clot retraction?
  14. Two outcomes of a blood clot?
    • 1. can be invaded by fibroblasts and form connective tissue, promoted by PDGF, 1-2 weeks
    • 2. dissolve
  15. Three essential steps of blood coagulation?
    • 1. formation of a complex of activated substances called prothrombin activator, rate limiting step in blood coagulation
    • 2. The activator catalyzes prothrombin to thrombin in the presence of calcium
    • 3. Thrombin convers fibrinogen to fibrin
  16. Prothrombin activator is formed in result of?
    • vascular damage
    • damage to special substances in the blood
  17. Name and function of GPIIb/IIIa?
    prothrombin receptor, on the cell membrane of platelets already bound to damaged tissues
  18. 2 alpha-2-globulins
    prothrombin and bradykinin
  19. Does fibrinogen leak of of vessels?
    • no, it is too large.
    • During pathological conditions vascular permeability can increase enough to let it out
  20. Reticulum of a blood clot?
    Long fibrin chain attached to clot
  21. Fibrin stabilizing factor, site of storage and function.
    released by activated platelets and cross links fibrin monomers by covalent bonds
  22. Origin of serum?
    • after a clot is formed the platelets contract and squeeze out all the fluid, this fluid is serum.
    • does not contain clotting factors
  23. Failure of a clot to retract indicates?
    low platelet level
  24. Platelets release what that cause clot contraction?
    ATP and calcium to activate actin/myosin and thrombosthenin
  25. Thrombin is proteolitic
  26. factors activated thrombin act on
    2, 8, 9, 10,11, and 12
  27. three initiating events of prothrombin activator formation
    • 1. trauma to vascular wall
    • 2. trauma to blood
    • 3. contact of blood with collagen
  28. Two pathways of prothrombin activator?
    • Intrinsic- damage to blood
    • Extrinsic-damage to vascular wall
  29. Factor that activates prothrombin activator?
  30. What is released form damaged blood vessels to initiate the extrinsic pathway?
    tissue factor, tissue throboplastin
  31. Two main proteins of prothrombin activator
    • X and V and calcium
    • factor X is the protease in this complex, V accelerates the action
    • thrombin itself has posotive feedback on factor V
  32. Initiation of the intrinsic pathway?
    • blood trauma, release of factor XII (activated when it contacts collagen surface or glass)
    • exposure of of blood to collagen
  33. Cleavage of XI by XII needs?
    HMW kininogen, accelerated by prekallikrein
  34. Activation of X in the intrinsic pathway by?
    VIII and IX
  35. Steps on blood coagulation that do not need calcium
    XII activating XI and XI activating IX
  36. Function of citrate ion?
    De-ionize calcium to stop coagulation in collected blood
  37. Function of oxalate ion?
    precipitate calcium out of solution to prevent clotting
  38. Speed of two clotting pathways?
    extrinsic is much faster then intrinsic
  39. Three factors that prevent clotting in the normal endothelium?
    • 1. smoothness of endothelium
    • 2. layer of glycocalyx, mucopolysacharide
    • 3. thrombomodulin and heparin on surface
  40. Two function of thrombomodulin in anticoagulation?
    • binds thrombin and removes it from circulation
    • complex activates protein C which cleaves V and VIII and causes the release of t-PA
  41. Two most powerful thrombin removers?
    ATIII and fibrin mesh (prevents the spread of clot)
  42. Largest site of heparin production?
    mast cells, large amounts in lung and liver to stop the coagulation of slow moving venous blood
  43. Plasmin substrates?
    I, V, VIII, XII
  44. Plasmin is caught in the fibrin mesh and combined into the clot
  45. Disease or damage to what organ can cause bleeding problems
  46. 5 vit K d├ępendent coagulation factors?
    II, VII, IX, X, protein c
  47. Cause of vit K deficiency?
    liver fails to secrete bile into the GI tract, obstruction of the bile duct or liver disease, prevents adqauate fat absorption
  48. Inheritance of hemophilia A
    x linked
  49. two compound of factor VIII
    factor VIII and von willebrands factor (protects factor 8 in circulation)
  50. difference in bleeding with hemophilia a and thrombocytopenia?
    thrombocytopenia is small vessels and hemophilia in large
  51. thrombocytopenia purpura
    spleenectomy and whole blood transfusion are helpful
  52. DIC?
    • widespread clotting in the circulation
    • usually occurs with large amounts of traumatized or dying tissue that releases tissue factor into the blood
    • can remove many clotting factors and eventually cause bleeding
  53. Clotting disorder with septicemia
    DIC, caused by bacteria or endotoxins, part of the reason septic shock is lethal.
  54. Time for warfarin effect
    • 12 hours 50%
    • 24 hours 20% clotting power
  55. oxalate is toxic to the body
  56. can citrated blood be re-infused
    yes the liver will convert the citrate to glucose within a couple minutes
  57. what is hyperemia?
    increased blood flow to activated tissues
  58. PT time is a measure of what?
    concentration of prothrombin in the blood
Card Set