Blood Clotting Flashcards
How is the extrinsic pathway triggered?
Through trauma that releases tissue factor III.
What is the common end part of both pathways?
Factor X activation -> thrombin activation -> formation of fibrin clot
What are the domains called that keep prothrombin in its inactive form?
Kringle domains
How is thrombin activated?
proteolytic cleavage
Which part is dependent on vitamin K?
Formation of Gla residues. (Addition of carboxyl group to glutamate)
What is the purpose of Gla residues?
They allow interaction with the sites of damage and they bring together clotting factors.
They also allow prothrombin to bind with calcium ions.
How does thrombin act on fibrinogen?
It cleaves the fibrinopeptides from the central, globular domain of fibrinogen.
How is a clot stabilised?
Through the formation of amide bonds between side chains of lysine and glutamine.
Catalysed by transglutaminase.
Which factor is defective in classic haemophilia?
Factor VIII
What does Factor VIII do?
It accelerates clot formation
How does the body ensure continuation of clotting?
Positive feedback activation by thrombin
How is the intrinsic pathway triggered?
Through damage to the endothelial lining of blood vessels
