Haemostasis Flashcards
Which substances does the endothelium produce to stop things sticking to it?
- Heparans
- TFPI
- Thrombomodulin
Which factors cause platelets and coagulation factors to be activated?
- Abnormal epithelial surface
- Physiological activator
Describe the process when a blood vessel is damaged
- Platelet adhesion
- Primary platelet plug
- Fibrin formation
- Clot confined to area of tissue damage
- Clot lysis and tissue repair
Which structures on a platelets surface interact with other things in the blood?
- Glycoproteins - binding points for things to stick e.g. collagen
- Cell surface receptors - signal the activation of other cells
List the roles that platelets have in haemostasis
- Adherance
- Activation
- Aggregation
- Providing a phospholipid surface for coagulation
What is the function of Von willebrand factor?
It binds to proteins in particular factor VIII and is important in platelet adhesion at wound sites
Which clotting factor is deficient in haemophilia A?
Factor VIII
Which clotting factor is deficient in haemophilia B?
Factor IX
Name the intrinsic clotting factors?
XI, IX, VIII and prothrombin
Name the extrinsic clotting factors
VII and tissue factor
Name the three natural anticoagulants and how they work
- TFPI: binds to activated X and VII and switches them off
- Activated protein C: binds to activated VIII and V and inactivates them
- Antithrombin: binds to thrombin, XI, IX, VIII and X and inactivates them
Describe the process of fibrinolysis
- Production of t-PA and u-PA
- tPa cleaves plasminogen into plasmin
- Plasmin breaks down the clot into fibrin degradation products (e.g. D-dimer)
Name the inhibitors of plasmin
- Antiplasmin
- Macroglobulin
Name the different types of anti-platelets and how they work
- Clopidogrel, prasugrel and ticagrelor - inhibit ADP pathway
- Abciximab, tirofiban and eptifibatide - prevent the binding of fibrinogen to glycoprotein IIb/IIIa
- Aspirin inhibits the COX enzymes
How does warfarin work?
It binds to factors 2, 7, 9 and 10 and inhibits them
