Hematology Flashcards
(36 cards)
Which factor is the convergence point and common to both the intrinsic and extrinsic pathways?
Factor X
What is the function of fibrin?
Which factor cross links fibrin?
It combines with platelets to form a platelet plug, resulting in hemostasis.
Factor XIII helps cross link fibrin
What are the three functions of thrombin?
- Platelet activation
- Activation of factor V and VIII
- Converts fibrinogen to fibrin
What are the three functions of antithrombin III?
- Inhibits factors IX, X, and XI
- Bonds to and inhibits thrombin
- Binds to heparin
How do proteins C and S work?
Protein C: degrades fibrinogen, and factors V and VIII
Protein S: cofactor of protein C
both are vitamin k dependent
What does tissue plasminogen activator do?
Converts plasminogen into plasmin
What is the function of plasmin?
It degrades factors V and VIII, fibrinogen, and fibrin
- alpha 2 anti plasmin naturally inhibits plasmin
Which factor is the only one not synthesized by the liver?
Where is it synthesized?
Factor VIII
It is synthesized in the endothelium
What are the vitamin k- dependent factors?
Factors II, VII, IX, X, proteins C and S
What’s the normal half life of RBCs? Of platelets? Of PMNs?
RBCs: 120 days
Platelets: 7 days
PMNs: 1-2 days
What’s the function of thromboxane? Where is it released from?
What’s the mechanism of action?
Thromboxane causes vasoconstriction and increases platelet activation.
- it is released by platelets
- MoA: triggers calcium release, resulting in exposure of GpIIb/IIIa receptor, which allows for platelet-platelet and platelet-collagen binding
What is prostacyclin’s (PGI2) role?
Decreases platelet aggregation and promotes vasodilation
- it is releases by endothelium
What is the composition of cryoprecipitate?
When is it used?
- Cryoprecipitate is composed of: vWF, factor VIII, fibrinogen, and factor XIII
- It is used in Von Willebrand’s disease and hemophilia A
What is FFP composed of?
All factors, protein C, protein S, and antithrombin III
How does DDAVP work in terms of coagulation?
What other medication works the same way?
- DDAVP causes release of vWF and factor VIII from endothelium
- Conjugated estrogens work in the same way
What does prothrombin complex consist of?
Factor X, V, platelet factor 3, and prothrombin
- catalyze formation of thrombin
What factors does PT measure?
Factors II, V, VIII, and X
- it is the best measure for liver synthetic fxn
What factors does PTT measure?
All but factors VII and XIII
- doesn’t pick up factor VIII deficiency
What’s the therapeutic range of PTT for anticoagulation
PTT: 60-90 sec
What’s the function of von Willebrand factor?
Links GpIb receptor on platelets to collagen
What bleeding test is/are abnormal for Von Willebrand’s disease
Bleeding time (ristocetin test)
How many types of von Willebrand’s disease are there? What’s the treatment for each?
Three types
- types I and III: due to reduced quantity circulating vWF
- treatment: recombinant VIII, DDAVP, cryoprecipitate,conjugated estrogen
- type II: defect in vWF
- treatment: recombinant VIII, cryoprecipitate
What’s the difference between hemophilia A and B? Which blood tests are abnormal? What are the treatment differences?
Hemophilia A: deficiency in factor VIII
- treatment: cryoprecipitate, recombinant VIII
Hemophilia B: deficiency in factor IX
- treatment: factor IX concentrate, FFP
PTT Prolonged and PT normal in each
What bleeding studies are abnormal in factor VIII deficiency? What’s the treatment?
Prolonged PT, normal PTT
- treatment: FFP, recombinant factor VII
