Haemostasis 2 Blood coagulation
Coagulation is referred to in this lecture as the fibrinogen turning to fibrin
Intrinsic and extrinsic pathats
Extrinsic
tissue factor factor 7a activates factor x
intrinsic pathway (needs negatively charged surface to activate as well as calcium and phopsolipid) factor 12 to factor 11 to factor 9 with factor 8 make factor 10
factor 10 and factor 5 lead to activaaitno of thrombin (intrinsic and extrinsic meet here)
coagulation factors need calcium and phospholipid to work thrombin leads to increase of platelet recruitment and fibrin creation
fibrin and fibrinogen structure
fibrin coagulative structure
Fibrin is continuously degraded by plasmin D dimers are a product of this degradation and may be used as a biomarker
Role of tissues in clotting
liver produces a large amount of clotting factors
endothelium makes factor 8 and von willenbrand factor
role of vitamin K
Vitamin K is needed for gamma carboxylation of glutamate which is needed for activation of clotting factors Warfarin blocks vitamin k regeneration
Inhibitors
antithrombin irreversibly binds to activated clotting factors eg Xa protein c and s stops cofactors factor 8a and 5a
Plasmin
Tpa binds with PAI and catalyses the transformation of plasminogen to plasmin plasmin is inhibited by plasmin inhibitors
overall there is an equilibrum between clotting and inhibition/ fibrin breakdown