Haemostasis Flashcards
(25 cards)
name components lining the endothelium which allow nnormal blood flow/ stop coag?
NO, Heparins, TFPI, Thrombomodulin, prostacyclin
wahta re the signals for activating platelets and coag factors?
abnormal cell surface, physiological activator
what does the open canillicular system allow?
SECRETION OF INTERNAL COMPONENTS
what do Alpha granules secrete?
Von Willebrand Factor and Thrombin
what do dense granules secrete?
ADP/ATP, Ca, Serotonin
how does adhereance of platelets occur?
VWF to GP1b, thrombin to GP1a, fibrinogen to GP2b
how does asprin work?
stops platelets aggregating
what is the role of platelets in haemostasis?
adhere, activation, aggregation and provide a phosphilipid surface for coagulation.
VWF binding sites
binds Patelets to collagen
what happens to fibrinogem to allow the cascade to complete?
cleaved by the prothrombin –> thrombin activation (domino cascade)
what may stop the cascade?
Haemophilia or anticoag drugs.
3 key natural anticoagulants (how do they each work)?
tissue factor pathway inhibitor, activated protein C and S, Antithrombin
outline Fibrinolysis
endothelium produced TPA (proteases) and UPA, (plasminogen activators) - TPA cleaves plasminogen into plasmin - this fragments the clot - producing fibrin degredation products e.g. D-Dimer
what does ASPRIN do?
REDUCES PLATLET AGGREGATION - inhibits cyclooxygenase from working, inhibits arachadonic acid from turning into thrmoboxane A2.
what drugs stop ADP from starting the aggregation in platelets?
Clopidogrel, Prasugrel, Ticagrelor
which drugs prevent the binding of fibrinogen to GP2b/a?
Abciximab, Tirofiban, Eptifibatide
Anticoagulant - WARFARIN
it is a vitmain K antagonist thus it inhibits Factors 2,7,9,10 from being carboxylated- Prevents the post translation of these factors from being activated .
Anticoagulant - HEPAIRN
binds to antithrombin, increases its activity - preventing thrombin formation
what drugs effect factor 10a? - anticoagulants such as…
Rivaroxaban, Edoxaban, Apixaban
what is the target INR
2 to 3
how would you commence someone of warfarin?
take a basline inr, then commence on iv warfarin until inr reaches therapeutic level over 2 days.
if INR is 9.7 and there is bleeding what would you do?
control bleeding, give vit k, withhold warfarin until the inr has stabilised
name 3 antiplatelet drugs
asprin, clopidorgel, dipyridamole, adciximab, the BANS.
what drugs decrease the activity of warfarin?
antibiotics, laxatives, cimetidine, phenylbutazone
