hemostasis Flashcards
hemostasis
using platelets, coagulation factors, and fibrin to stop bleeding after injury to vessels
coagulation factors
- zymogen
- -> k dependent
- -> K independent
- cofactors
- non protein cofactors
- fibrinogen and factor XIII
k dependent coagulation factors
2, 7, 9, 10, C, and S
intrinsic pathway
12 –> 12a
11 –> 11a
9 –> 9a
8 –> 8a
extrinsic pathway
7 + TF –> 7 a
calcium
phospholipid bilayer
common pathway
X –> Xa
prothrombin
factor II; forms thrombin
thrombin
activates fibrinogen to form fibrin
fibrinogen
D – E – D
BB AA Y
fibrin
B and A
d-dimer
molecule degradation product of cross-linked fibrin; it reflects ongoing activation of the hemostatic system
with a patient who has a low pretest probability of clot … d-dimer would help rule out clot if the results are
negative
primary hemostasis
vasoconstriction and platelet
secondary hemostasis
coagulation factors
tertiary hemostasis
fibrin
platelets are formed from
megakaryocytes cytoplasm
platelet lifespan
7-10 days
non-protein cofactor
calcium and phospholipid surfaces
factor XIII
cross-links fibrin
cofactor coagulation factors
5 and 8, tissue factor, and von willebrand factor
coagulation factors with the shortest half life and smallest plasma concentration
factor 7, 8, and protein C
activated platelets release granules
ADP, thromboxane A2 and recruit more platelets and promote aggregation
platelet glycoprotein IIb/IIIa
intergrin receptors; adhere to fibrinogen, enhance aggregation and stabilize thrombus
fribin stabilizes the
the growing platelet thrombus
endothelial cells release
- prostacyclins
- nitric oxide
both of which inhibit further platelet aggregation
prostacyclin
It inhibits platelet activation and is also an effective vasodilator.
thrombin has both procoagulant and anitcoagulant properties. What makes it an anticogulatant
complexed with thrombomodulin