Flashcards in Hematology - Hemostasis 2 Deck (82)
______ is needed for medium/large vessels.
What cells are key players for secondary hemostasis?
Platelets and fibroblasts
What proteases are involved in secondary hemostasis?
FXIa, FIXa, Fxa, FIIa, and FVIIa
What cofactors are involved in secondary hemostasis?
Tissue factor (FIII), FVa, and FVIIIa
What crosslinkers are involved in secondary hemostasis?
What activators are involved in secondary hemostasis?
What inhibitors are involved in secondary hemostasis?
Antithrombin, protein C, and protein S
What is the end result of secondary hemostasis?
Generation of thrombin which forms a crosslinked fibrin clot
Secondary hemostasis is a series of enzymatic reactions involving what three main things?
Coagulation factors, calcium, and Phosphatidylserine on platelets
What does thrombin (FIIa) do?
It cleaves fibrinogen (FI) into fibrin
How does fibrin form the fibrin clot?
It is cross-linked to form the fibrin clot by FXIIIa
What is the extrinsic pathway composed of?
Tissue factor (TF), FVII, and calcium
What is the intrinsic pathway composed of?
FXII, FXI, and FIX, FVIII, calcium, and phosphatidylserine
What is the end result of the intrinsic pathway?
FIXa and cofactor FVIIIa to activate X into Xa
What factors are involved in the common pathway?
Fxa, prothrombin (FII), FXIII (crosslinker), FV, calcium, and phosphatidylserine
What tests assess the functionality of both the intrinsic and common pathways?
Activated partial thromboplastin time (aPTT) and activated coagulation time (ACT)
What test assesses the functionality of the common pathway alone?
Thrombin clot time (TCT)
What tests assess the functionality of both the extrinsic and common pathways?
Prothrombin time (PT) and PIVKA
What is involved in the initiation phase of the cell-based model?
Extrinsic pathway, tissue factor, and the cell surface of fibroblasts
What is involved in the amplification phase of the cell-based model?
Intrinsic factor, thrombin, and the cell surface of the platelet
What cell surface is associated with the propagation phase of the cell-based model?
What are the functions of thrombin?
Activation of the intrinsic patway (FXI, FVIII, and FV to make more thrombin), activation of FXIII to crosslink fibrin, cleaves fibrinogen into soluble fibrin, and activation of platelets for more surface for the intrinsic pathway
Which model of secondary hemostasis explains what goes on in the body better?
the cell based model
What can go wrong with secondary hemostasis?
Too few or too many coagulation factors and antagonized or inactive vitamin K
What are the inherited coagulation disorders?
Hemophilia A and B
What coagulation factor is deficient in hemophilia A?
FVIII (8) deficiency
What coagulation factor is deficient in hemophilia B?
FIX (9) deficiency
What are the acquired causes of coagulation disorders?
Anticoagulant rodenticide, DIC, and Liver disease
How does DIC result in a coagulation disorder?
it consumes clotting factors