L3 Hemostasis Flashcards
Components of hemostatic system
Vascular wall
Platelets
Coagulation proteins
Platelet response to vascular injury: Primary hemostasis
Adhesion
Activation
Aggregation
Adhesion
Glycoprotein Ib/IX binds to subendothelial collagen, mediated by Von willebrand factor
Activation
Platelets bind to vWF Change from disc to sphere Cytoplasmic ADP IIb/IIIa receptor activation Actin fibers contract platelet
Aggregation
Release Cyto ADP
Activation of adjacent cells
Platelet binding thru fibrinogen and gp IIb/IIIa receptor
Fibrin monomers are covalently cross linked by
Factor XIII
Coagulation cascade
Look at notebook
Protein C system
Enzyme
Cofactor
Enz: Activated protein C
Cof: Protein S
Regulation of Primary hemostasis
NO
PGI2
ADPase
Regulation of secondary hemostasis
Serine protease inhibitors (antithrombin)
Protein C pathway
Fibrinolytic system
Factor V Leiden mutation
Resistance to inactivation by protein C/S complex
Prothrombin time
In the presence of..
Extrinsic or Intrinsic
Test during what therapy
Time need for plasma to form clot in presence of tissue thromboplastin and Ca
Measures extrinsic (VII, X, V, II, I)
Coumadin/Warfarin
11-13 seconds
Partial thomboplastin time
In the presence of..
Extrinsic or Intrinsic
Test during what therapy
time needed for plasma to colot in presence of Ground glass or kaolin (VII), cephalin, and Ca
Intrinsic (12,11,9,8,10,5,2,1)
Heaprin therapy
28-35 sec
Normal platelet count
150,000-400,000/uL
Thrombocythemia
Thrombocytopenia
Thrombocytosis
Increase
Decrease
Increase
in platelet number
