Hematology Flashcards
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