bleeding and thrombosis Flashcards
what happens as a result of blood vessel damage
normal flow is altered
collagen is exposed
blood vessel releases TF
adrenaline is released
function of platelets in blood vessel damage
detect abnormal surface (collagen)
become activated
have glycoproteins that bind to clotting factors
how do platelets stick to collagen
via glycoproteins on their cell surface
von willebrand factor is important for platelet adhesion
what is aggregation
when the phospholipids on the internal surface of the platelet move to the external surface
what enzyme is involved in aggregation
scramblase
what is the purpose of aggregation
creates a site for coagulation reactions
how does a primary platelet clot form
platelets all stick together via glycoproteins
how is fibrin produced
thrombin binds to fibrinogen and cleaves it producing fibrin
what is fibrinogen
precursor of fibrin
requires all the clotting agents to be working for it to become cleaved
how is thrombin formed
factor X cleaves prothrombin into thrombin
what is a clot made up of
platelets and fibrin mesh
what is t-PA and u-PA
molecules released by endothelial cells that cleave plasminogen to male plasmin
what does plasmin do
breaks down fibrin clot
plasminogen inhibitors
PAI-1
PAI-2
what is the main source of PAI-1
adipose tissue
what are d-dimers
fibrogen degeneration products
raised if there has been thrombosis
what is TFPI
natural anticoagulant
how does TFPI work
inhibits factors 7 and 10
this means less thrombin will be produced
what is protein C
natural anti-coagulant
function of protein C
binds to it’s cofactor protein S and switches off factors 8 and 5
what can deficiencies in natural anticoagulants lead to
coagulopathies like DVT
what is vitamin K needed for
post translational modification of factors 2,7,9,10
how does aspirin work as an anti-coagulant
blocks COX pathway
this prevents aggregation
how does Clopidogrel work
block ADP on platelets to prevent activation
what drugs block GP 2/3
abciximab
tirofiban
eptifibatide
how does warfarin work
blocks factor 10, 9, 7
how do heparins work
bind to anti-thrombin and allow it to cleave thrombin faster
what drugs bind to factor 10
rivaroxaban
edoxaban
apixaban
what drugs are direct thrombin inhibitors
dabigatran
bivalirudin
