Coagulation Cascade Flashcards
What causes the primary hemostasis
The injury to the blood vessel
When platelets are activated, what do the expose in their conformational change
A phospholipid platform which allows for adhesion of other platelets
Define tissue factor
Produced by injured endothelial cells
Converts FVII to FVIIa in the extrinsic pathway
Other name for:
FI FII FIII FIX FX FXII FXIII
Fibrinogen Prothrombin TF Christmas Factor Stuart-Power Factor Hageman Factor FSF
What are the Vit-K dependent factors
II, VII, IX, X
What does Vit. - K do
Introduces Ca binding sites via y-carboxylation of glutamic acid which allows these factors to use Ca and fully function
What does PTT test for
Intrinsic pathway
XII, HMWK, XI, IX, and VIII
What does PT test for
Extrinsic pathway
VII
What can an abnormal PTT test indicate clinically
Heparin therapy
Hemophilia A or B
Define Hemophilia A factor issue
FVIII
Define Hemophilia B issue
FIX
What does PTT ACTUALLY LOOK AT
The clotting time from FXII to fibrin clot in the intrinsic pathway
What can PT indicate clinically
Coumadin therapy
Vit. K deficiency
What does PT actually look at
Clotting time from FVII to fibrin clot in the extrinsic pathway
What is the extrinsic pathway activated by
External trauma
What is the intrinsic pathway activated by
Trauma inside the vascular system, and activated by platelets, exposed endothelium, or collagen
Vit. K is not active till when
Converted from its quinone form to its quinol form in the liver
What converts Vit. K from Vit K 2,3-epoxide to quinone form
Vit. K 2,3 - epoxide reductase
What converts quinone Vit. K to active quinol Vit. K
Quinone reductase
What does wardarin act on
Decreases the activity of Vit. K - epoxide reductase, which increases the time it takes for clot to form
What is the more active form of warfarin and what is it metabolized by
S-warfarin which is metabolized by CYP2C9
Which factors have the longest half-life
What about the shortest
FII and FX
FVII
What does an increased PT and a decreased PTT mean
Liver disease and decreased Vit. K and VII
What does a normal PT and prolonged PTT mean
Defective intrinsic pathways, vWD, lupus
What does it mean if both PT and PT are prolonged
Defective FI, II, V, or X, severe liver disease, or warfarin OD
What is the purpose of HMWK
Acts as a cofactor with XII to attract it to the charged surface of the platelet
What is the purpose of Kallikrein
Accelerates conversion of XII to XIIa through positive feedback
