Hemostasis Flashcards
What is endothelin?
Vasoconstriction
What does the endothelial tissue release initially in damage?
Endothelin
What is the primary hemostatic plug?
Platelet adhesion and aggregation
What is the secondary hemostatic plug?
Activation of clotting cascade
Thrombin activation and fibrin network
What is the final step in hemostasis?
Fibrinolysis: breaking down of the scab
What do the platelets in the primary plug bind to?
Collagen
What is needed for platelets adhere?
Glycoproteins
von Willebrand factor
Collagen
What induces conformational changes in platelets?
ADP and thromboxane A2
How does aspirin stop clotting?
Inhibiting thromboxane A2
What is the intrinsic pathway?
Only involves factors in vasculature
What is the extrinsic pathway?
Only involves factors outside the vasculature
First factor in intrinsic pathway
Factor XII
First factor in extrinsic pathway
Tissue factor
Factor VII
What is needed for an intrinsic response?
Net negative charge on the endothelium
What does Coumadin do?
Blocks vitamin K synthesis
What does vitamin k do?
Cofactor in enzymes needed for post-trans mods on factors 2 7 9 10
What does the partial thromboplastin time (PTT) assay test?
Measures activity of proteins in intrinsic pathway
What does the prothrombin time (PT) assay test?
Measures activity of proteins in extrinsic pathway
What do the tests not tell?
Which clotting factor specifically are deficient
What does thrombin do?
Cleaves fibrinogen to form fibrin
Activates platelets
Pro-inflammatory effects
What is unique about thrombin?
Can be pro or anti coagulation
How do you prevent thrombosis?
PGI2, NO, and ADPase
