Hemostasis Flashcards
efficient platelet adhesion to ECM requires what factors?
- vWF (subendothelial ECM)
2. GpIb (platelet)
what links the platelet to the endothelium?
vWF
besides platelets, what else does vWF bind? what is the purpose?
- factor VIII (coagulation factor)
2. prolongs half life, localizes it
where is integrin a2b1 found? what does it do?
- platelet
2. helps adherence to ECM
what causes the dramatic shape change of activated platelets?
Ca2+ signal
what is the role of TXA2 in the blood?
- vasoconstriction
2. platelet activation signals
how is TXA2 made?
- arachadonic acid release upon platelet activation
- arachadonic acid + COX = PG2
- PG2 gives rise to TXA2
what are the roles of ADP in the blood?
- platelet activation
- triggers change in GpIIb - GpIIIa receptor on platelets - allows receptor to bind fibrinogen for initial plug formation
what is the most common bleeding disorder?
vWF disease
how is vWF disease managed?
desmopressin - releases vWF from storage sites in endothelium
what characterizes bernard-soulier syndrome? pathogenesis?
- platelets fail to aggregate in response to stimuli
2. defect in interaction between vWF adn GpIb
what characterizes glanzmann thrombasthenia? pathogenesis?
- platelets fail to aggregate in response to various stimuli
- defect in GpIIb and / or GpIIIa
the coagulation cascade ultimately leads to activation of what compound?
thrombin
the intrinsic and extrinsic pathways converge on the activation of what factor?
factor X (results in activation of thrombin)
what is the key regulator of coagulation?
factor X
partial thromboplastin time test tests which arm of the coagulation cascade?
intrinsic