Coagulation pathways Pathway Flashcards
The extrinsic pathway is inhibited by which drug?
Warfarin
Extrinsic pathway is activated by ?
Vascular injury or when vessel wall comes into contact with blood.
Extrinsic pathway is measured by?
PT and INR
List the three steps of the extrinsic pathway
- Tissue factor release
- Factor 10 activation
- Prothrombin Activator (Prothrombinase)
Explain the steps of the extrinsic pathway
- Tissue trauma liberates TF from the subendothelium
- TF activates factor 7
- Factor 7 activates factor 10 in the presence of Ca
- Prothrombin activator and platelet phospholipids activate factor 2 ( thrombin)
- 5 is a positive feedback mechanism that accelerates the continued production of prothrombin activator
The extrinsic pathway is fast and requires only _______
15 seconds
Prothrombin activator is?
A collective name that refers to the collection of coagulation factors that lead to thrombin activation 2a
Which factor is the first to be deficient in patients with liver disease and why?
Factor 7 since it has the shortest half life of all the coagulation factors (4-6hrs)
What is the half life of factor 7 ( antihemophilic factor)
4- 6 hrs
Intrinsic pathway is activated by?
Blood trauma
PTT and ACT measures which pathway?
Intrinsic pathway
Intrinsic pathway includes which factors?
12, 11, 9, 8
Count backward from 12 skipping 7
________. pathway is inhibited by heparin
Intrinsic
___________ is also called contact activation pathway?
The classical intrinsic pathway.
What is the first step of the intrinsic pathway
Blood trauma exposes collagen activating factor 12
What is the second step of the intrinsic pathway
Factor 11 activation
- Factor 12a activates 11
- Step requires HMW kinogen
- Step accelerates prekallikrein
What is the third step of the intrinsic pathway
Factor 9 activation- Factor 11a activates factor 9
What is the fourth step of the intrinsic pathway
Factor 10 activation
- Factor 9a and 8 activate 10
- Factor 8 is missing with hemophilia A
- Platelets are missing with thrombocytopenia
What is the 5th step of the intrinsic pathway
Prothrombin Activator (prothrombinase)
- Prothrombin activator and tissue phospholipids activate thrombin (factor 2a)
- This step in the intrinsic pathway is identical to the last step of the extrinsic pathway
The intrinsic pathway is slower requiring up to _________ minutes to form a clot
6 minutes
The primary goal of both the intrinsic and extrinsic pathway is?
To produce prothrombin activator (prothrombinase)
The final common pathway begins when?
Begins when prothrombin activator changes prothrombin (2) to thrombin (2a)
__________ is a proteolytic enzyme that changes fibrinogen to fibrinogen monomer
Thrombin (2a)
After platelets aggregate , _______ is incorporated into the platelet plug
fibrin