Flashcards in 281b - platelet fxn Deck (13):
where does thrombin generation occur? how?
surface of platelets
scramblase --> negative PL on outer lipid membrane --> factors and Ca assemble
signs of platelet defects?
easy bruising, petechiae
what controls proplatelet formations in MK?
microtubules w/ motors --> extended from BM into vessel sinuses
10 days --> apoptosis
consumed earlier in normal endo fxn too
released when platelets activated and change shape
dense = ADP, Ca (Small molecules)
alpha = fibrinogen, vWF (proteins)
immune thrombocytopenia - autoimmune disorder
abs --> GPIIb/IIIa
what do normal endothelial cells have for antiplatelet activity?
ecto-ADPase (CD39) on surface
what do platelets binds on damaged endothelium?
collagen via vWF - GPIb --> rolling
fibrinogen receptors - GPIIb/IIIa --> aggregation
hereditary defects of platelet fxn?
bernard-soulier syndrome = GPib + very large platelets
Glanzmann thrombasthenia = GPIIbIIIa
platelet fxn disorders - acquired
drugs (ASA, NASIDS)
dysporteinemia (high IgA)
CV bypass -> exhuastion from abnormal surface
hereditary defects of platelet fxn
bernard-soulier syndrome = GPib
Glansmann thrombasthenai = GPIIbIIIa
phospholipase A2 fxn in platelets?
converts PL from membrane --> TxA2 --> platelet agonist --> aggregation