Haemostasis Flashcards
what does the endothelium of blood vessels produce?
heparins TFPI - Tissue factor pathway inhibitor thrombomodulin NO Prostacyclin
what forms a clot?
platelets
vWF
Coagulation factors
what makes sure that a clot remains confined to the site of injury?
natural anticoagulants
what signals cause the resting platelets and coagulation factors to become activated?
abnormal surface
physiological activator
first stage in vessel damage (use diagram)
Platelet adhesion to subendothelial collagen
von willebrand factor sticks to collagen and platelets
what does the subendothelial collagen produce?
physiological activator
what cell surface receptors are found of platelets?
ADP receptor
Epinephrine receptor
thrombin receptor
what platelet glycoproteins are found on the surface?
VI
Ia/IIa/
Ib/V/IX
IIb/IIIa
on platelets what does IIb/IIIa bind to?
fibrinogen
on platelets what does Ib bind to?
vWF
on platelets what does Ia/IIa bind to?
collagen
name the roles of platelets in haemostasis
adhere
activation
aggregation
provide phospholipid surface for coagulation
using a diagram describe the process of platelet adherance
see notes
using a diagram describe the process of platelet activation
see notes
using a diagram describe the process of platelet aggregation
see notes
using a diagram describe the process of platelet coagulation
see notes
vWF has binding sites for?
FVII
GPIb
Heparin
Collagen
what factors are necessary for clotting?
F XII XI IX VIII X Prothrombin fibrinogen
what factor is deficient in haemophilia B?
IX
what factor is deficient in haemophilia A?
VIII
describe the extrinsic pathway of fibrin formation
see notes
describe the intrinsic pathway of fibrin formation
see notes
name the most natural important anticoagulants
Antithrombin
TFPI
Activated protein C=protein S
using a diagram describe the actions of TFPI in anticoagulation
binds to and inactivates VIIa and Xa
using a diagram describe the actions of proteins C and S in anticoagulation
Va
using a diagram describe the actions of AT in anticoagulation
thrombin XIa IXa VIIIa Xa
using a diagram describe the process of fibrinolysis including natural inhibitors
endothelial cells produce plasminogen activators
tissue plasminogen activator = tPA
plasminogen has bridge which is cleaved by TPA to plasmin
plasmin breaks the fibrin clot down
degradation products
d-dimer = fibrin broken down by plasmin
natural inhibitors of plasminogen and plasmin
a2-antiplasmin can be issue in liver transplantation which ends up excessive fibrinolysis therefore bleeding occurs
using a diagram describe the MoA of aspirin
see notes
using a diagram describe the MoA of clopidogrel/prasugrel/ticagrelor
see notes
using a diagram describe the MoA of abciximab/tirofibal/eptifivatide
see notes
using a diagram describe the MoA of warfarin
Warfarin decreases blood clotting by blocking an enzyme called vitamin K epoxide reductase that reactivates vitamin K1.[5]Without sufficient active vitamin K1, clotting factors II, VII, IX, and X have decreased clotting ability.
using a diagram describe the MoA of heparins
see notes
using a diagram describe the MoA of rivaroxaban/edoxaban/apixaban
see notes
when are the DOACS commonly used?
prevention of stroke, systemic emboli in AF
using a diagram describe the MoA of dabigatran/bivalirudin/argatroan
see notes
