Haemostasis and Blood Coagulation Flashcards
What are the components of normal haemostasis?
- Blood vessel wall
- Platelets
- Von Willebrand factor
- Congulation factors
- Fibrinogen
How do endothelial cells regulate haemostasis?
Are negative regulators, stop platelets from being activated
What mediators do the endothelial cells have?
- Prostacyclin
- NO
- Endothelial Protein c receptor
- Thrombomodulin
- Heparans
What activators of haemostasis does the sub/endothelium contain?
- Collagen
- Tissue Factor
- Von Willebrand Factor
What are platelets?
Small circulating fragments of cytoplasm formed in bone marrow by megakaryocytes
What are the roles of platelets in haemostasis?
- Adhere to subendothelial proteins after vascular damage
- Activate and aggregate with other platelets
- Support the activation of coagulation factors
What is von willebrand factor?
Complex adhesive plasma protein synthesised by the vasuclar endothelium
What are the roles of Von Willebrand Factor in haemostasis?
- Binds platelet surface proteins to mediate platelet adhesion
- Stabilises circulating coagulation factor VIII
What are coagulation factors?
A series of soluble zymogen proteins in plasma
What is the role of coagulation factors in haemostasis?
- Assemble into functional tenase and protrombinase complexes on the surface of activated platelets
- Results in rapid burst conversion of prothrombin to thrombin
What is fibrinogen?
Multi-domain, complex high molecular weight protein abundant in the plasma
What are the roles of fibrinogen in haemostasis?
- Binds platelet surface integrins to mediate platelet aggregation
- Polymerised by thrombin to form fibrin clot
