Blood Detail Flashcards
Clotting factors are made where?
in the liver, except VIII (vascular endothelium)
intrinsic pathway
contact activation. blood contacts collagen. slower, forms larger clots
intrinsic pathway sequence
exposed collagen, XII, XI, IX, X
extrinsic pathway
tissue factor initiated. faster (15s), less thrombin, smaller clot
extrinsic pathway sequence
trauma, III, VII, X
exposed collagen–>
XII
XIIa–>
XI
XIa (or VII/TF)–>
IX/VIII/platelets
IX/VIII/platelets–>
V/X/platelets
X (prothrobin activator), V (from platelets)
damaged tissue–>
VII/TF
VII/TF–>
V/X/platelets (prothrombin activator)
V/X/platelets
FII (prothrombin)–> thrombin–>
FI (fibronogen) to fibrin
coagulation cascade is
secondary hemostatis
fibrin is
a woven rope of 3 chains (2 alpha, 2beta, 2 gamma) , acts as glue for platelets
fibrin ropes are crosslinked by
a transglutaminase, FXIIIa
Which CFs and anticoagulants depend on vitamin K?
FII, FVII, FIX, FX, Protein C and S
for binding Ca
Warfarin and Coumadin block
vitamin K, prevent clotting factors from attachment to platelets
Tenase complex
allows FX activation. IXa, VIIIa
IXa linked to
hemophilia B
VIIIa linked to
hemophilia A
circulating VII adheres to
non-endothelial cells that express Tissue Factor
which have become exposed to the blood due to damage. VII is then autoactivated
tertiary hemostatis: XII–>XIIa
cleaves kallirein, activating plasminogen to plasmin,
tertiary hemostatis: urokinase and tPA
also generate plasmin
plasmin
binds and deactivates V, VIII, fibrin to dissolve clots
detect clotting and clot reabsorption
fibrin degradation products (FDPs or d-dimers)
Protein C and S (with thrombomodulin)
inactivate FV and FVIII
platelets 150,000
normal
platelets 100,000
bleeding in surgery
platelets 20,000
bleeding in acute illness
platelets 10,000
spontaneous injury
WASp syndrome
X-linked disease (mainly males) thrombocytopenia, eczema, recurrent infections, and small-sized platelets
Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT)
both caused by WASp mutation: thrombocytopenia and small platelets are the only consistent features of WAS and XLT
thrombocytopenia
relative decrease in platelets