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2014-05-19 14:20:23
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  1. Name each blood coagulation factor including all names
    • I Fibrinogen
    • II Prothrombin
    • III Tissue Thromboplastin, Tissue factor
    • IV Ionized Calcium
    • V Labile factor, proaccelerin
    • VI
    • VII Stable factor, serum prothrombin conversion accelerator (SPCA), proconvertin
    • VIII Antihemophilic factor A
    • VIII:C or VIII:AHF coagulant portion
    • VIII:vWF von Willebrand portion
    • IX Christmas factor, plasma thromboplastin component (PTC), antihemophilic factor B
    • X Stuart-Prower factor
    • XI Plasma thromboplastin antecedent (PTA)
    • XII Hageman factor, contact factor
    • XIII Fibrin stabilizing factor (FSF)
    • HMWK Fitzgerald factor, High-molecular-weigh-kininogen (HMWK)
    • PK Fletcher factor, Prekallikrein (PK)
  2. List the blood coagulation factors grouped by function
    • Substrate: Factor I
    • Cofactors: Factors V and VIII:C(AHF)
    • Enzymes; Proteases: activated forms of II, VII, IX, X, XI, XII, PK
    • Enzymes; Transaminase: activated form of XIII
  3. List the blood coagulation factors grouped by physical properties w/ info about grouping
    • Fibrinogen group: I, V, VIII, XIII
    • high MW proteins
    • also found in platelets
    • acted on by thrombin
    • consumed during coagulation
    • NOT vitamin K dependent for synthesis
    • Prothrombin group: II, VII, IX, X
    • low MW proteins
    • contain gamma carboxyglutamic acid
    • not consumed during coagulation (except II)
    • vitamin K dependent for synthesis
    • Contact group: XI, XII, PK, HMWK
    • involved in initial phase of intrinsic system activation
    • not consumed during coagulation
    • not Vitamin-K dependent for synthesis
  4. Describe the Extrinsic pathway in words
    • (VII)
    • Injury occurs, fluid containing III (tissue factor)¬†enters blood stream¬†
    • III + Ca activates VII
    • VIIa and III activate the common pathway (X) and the intrinsic pathway
  5. Describe the Intrinsic pathway in words
    • (VIII, IX, XI, XII)
    • XII comes in contact with collagen and is activated
    • XIIa + HMWK + PK activate XI
    • Ca + XIa activate IX
    • PF 3 + VIII:C + Ca activate + IXa activate X (the common pathway)
  6. What is the tenase complex in the intrinsic and extrinsic pathways?
    • Intrinsic: IXa + Ca + PF 3 + Factor VIII:C
    • Extrinsic: VIIa + Ca + III
  7. Describe the common pathway in words
    • (I, II, V, X)
    • Tenase activates X
    • Xa + Ca + PF 3 + V activates II
    • IIa activates XIII AND I
    • I forms fibrin monomer
    • XIIIa + Ca form fibrin polymer (then fibrin clot)
  8. Describe thrombin's action on fibrinogen and the stabilization of a clot
    • Fibrinogen consists of alpha, beta, and gamma chains
    • Thrombin cleaves the alpha and beta chains of firbinogen resulting in a fibrin monomer + fibrino peptides A and B
    • Spontaneous polymerization of fibrin occurs (weak H bonds)
    • XIIIa and Ca stabilize the clot (cross-linked fibrin polymer)
  9. What tube is normally used for factor testing?
    NaCitrate (lt blue) within 2 hours
  10. What are the screening tests for hemostasis disorders w/ brief description
    • Platelet count
    • Bleeding time: std pressure + stick... how much time to stop bleeding?
    • Prothrombin time: tests for Extrinsic and common pathway (I, II, V, VII, X)
    • uses thromboplastin-calcium reagant
    • normal is 11-13s
    • Activated partial thromboplastin time: tests intrinsic and common pathways (I, II, V, VIII, IX, X, XI, XII)
    • uses partial thromboplastin (PF 3 substitute) and Ca reagant
    • normal is <35s
    • Thrombin time: tests conversion of fibrinogen to fibrin
    • uses thrombin reagant, no calcium
    • normal is 10-15s (15-22s)
    • Quantitative fibrinogen assay: tests conversion of fibrinogen to fibrin
    • normal is 200-400mg/dL
    • Evaluation of factor XIII: tests factor XIII activity
    • form plasma clot with thrombin
    • observe fibrin stabilized clot in 5M urea over time
    • will disseminate quickly if factor XIII issue
  11. Describe the acquired blood coagulation defects
    • Vitamin K deficiency: hemorrhagic disease of newborn, liver disease, oral anticoagulants (coumadin)
    • Heparin therapy: antithrombin
    • Acute disseminated intravascular clotting (DIC): massive injury releases too much III and clotting factors are used up
  12. Describe the hereditary blood coagulation defects
    • Classical hemophilia A: VIII:C deficiency
    • joint bleeding leading to swelling
    • von Willebrand's disease: VIII:vWF deficiency
    • bruising
    • hemophilia B (christmas disease): IX deficiency
    • Rare deficiencies: I, II, V, VII, X, XII
  13. Describe the fibrinolytic pathway
    • P. activator and Tissue P. activator activate plasminogen
    • Plasmin cleaves fibrinogen into FDP (fibrin degredation products) which can be measured
  14. Describe the laboratory evaluation of fibrinolysis
    • Latex particles are coated with antibodies to the D and E fragments of FDPs
    • D and E fragments cause particles to clump
  15. Describe the defects of fibrinolytic activity
    • Primary fibrinolysis: results in fibrin/fibrinogen split products (FSP), decreased V and VIII:C
    • Etiology: massive strep infections producing streptokinases
    • kidney cancers producing urokinases
    • trauma (crush) incidents