Antiplatelets and Anticoagulants Flashcards
what is haemostasis?
the arrest of blood loss from a damaged vessel
what is exposed when the vascular wall is damaged?
collagen
tissue factor (TF)
what is involved in primary haemostasis?
local vasoconstriction
adhesion, aggregation and activation of platelets
what do platelets do when activated?
extend pseudopods
release thromboxane A2
what is TXA2?
thromboxane A2
what does TXA2 cause?
mediator release
vasoconstriction
what mediators are released in response to TXA2?
serotonin
ADP
what does ADP do?
activates further platelets
aggregates platelets into a soft plug
what is the key event in the coagulation cascade?
production of thrombin, that cleaves fibrinogen to fibrin
what is factor IIa?
protease thrombin
what does thrombindo?
cleaves fibrinogen to fibrin
what does fibrin do?
forms a solid clot
what is inactivated factor X converted to, and what is involved in this process?
converted to active factor Xa by tenase
what is prothrombin converted to?
thrombin by prothrombinase
what is inactive factor II?
prothrombin
what is thrombosis?
pathological haemostasis
what are the predisposing factors for thrombosis?
virchow’s triad
- vessel wall injury
- abnormal blood flow
- increased coagulability of blood
what colour is an arterial thrombus and why?
white
mainly made of platelets in a fibrin mesh
where is an arterial embolus likely to lodge?
in an artery
what is used to treat an arterial thrombus?
antiplatelet drugs
what colour is a venous thrombus and why?
red
it is fibrin rich
where is a venous embolus likely to lodge?
the lungs
what is used to treat a venous thrombus?
anticoagulants
what part of the coagulation cascade is targeted by rivaroxaban?
factor Xa is inhibited
