Please enable JavaScript.
Coggle requires JavaScript to display documents.
Haemostasis (Components (Platelets, von Willebrands Factor (vWF), Vascular…
Haemostasis
-
Anticoagulant system
Protein C
Vitamin K-dependent protein
Activated by thrombin activating thrombomodulin
Inactivates FVa and FVIIa (extrinsic pathway)
-
-
Tissue factor pathway inhibitor
Forms complex with TF, FVIIa and FXa (extrinsic pathway)
Coagulation cascade
Intrinsic pathway (platelet activation - 12, 11, 9, 10)
FXII - FXIIa
FXIIa activates FXI - FXIa
FXIa activates FIX - FIXa
FIX activates FX - FXa, forms prothrombinase complex
Common pathway (FXa onward - 5, 10, 2, 1, 8)
Prothrombinase cleaves prothrombin to thrombin (FIIa)
Thrombin cleaves fibrinogen to insoluble fibrin to form stable clot
Extrinsic pathway (tissue damage - TF, 7, 10)
Vessel wall damage esposes TF in vessel walls and endothelium
TF activates FVII (FVIIa)
FVIIa activates FX (FXa), forms prothrombinase complex (FXa-FVa)
Phases
Primary - platelet plug
Vascular injury exposes subendothelial factors (TF, collagen, fibronectin, vWF)
Platelets adhere and are activated
Platelets express surface proteins (e.g. GP IIb-IIIa)
Platelets release granules containing pro-coag factors
Fibrinogen binds to GP IIb-IIIa on platelet surface causing platelet aggregation
Secondary - fibrin clot
Coagulation cascade activated, thrombin generated
Thrombin cleaves fibrinogen to insoluble fibrin
Platelets and fibrin crosslinked by FXIII for stable thrombus
RBCs also become enmeshed in clot
-
Definition
Physiological response to cessation of
bleeding and maintenance of vascular integrity
by formation of thrombus (platelets plus +fibrin clot)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-