Overview of Hemostasis Flashcards
what is hemostasis
the ability of the body’s systems to maintain the integrity of the blood and blood vessels
CLOTTING
4 main steps to achieve hemostasis
- primary hemostasis - form platelet plug
- secondary hemostasis - form mesh of fibrin
- fibrinolysis - removal of plug
- restoration of vessel patency - tissue repair
players in primary hemostasis
platelets and von Willebrand factor
players in secondary hemostasis
clotting factors
where are most coagulation factors produced
the liver
where is Factor III produced
endothelial cells
where are Von Willebrands produced
endothelial cells
which factors require Vitamin K for activation
II, VII, IX, X
proteins C and S
which Vitamin K factors have the shortest half life
Factor VII - 5 hours
factors in intrinsic pathway
XII, XI, IX, VIII
factors in extrinsic pathway
III, VII
factors in common pathway
X, II, I, XIII
thrombocytopenia
decrease in platelet count
thrombocytosis
increase in platelet count
thrombocytopathia
dysfunctional platelets
3 general ways to have thrombocytopenia
decrease in production
increase in consumption
sequestration
2 main causes for thrombocytosis
reactionary: chronic inflammation, iron deficiency, Cushings
primary: megakaryocyte leukemia
MPV definition
Mean Platelet Volume
BMBT definition
Buccal Mucosal Bleed Time
what does BMBT test for
platelet vessel interaction (primary hemostasis)
why is cuticle bleed not a great test to assess platelet function
difficult to standardize
painful
does not differentiate primary and secondary hemostasis
which tests can be used to assess the intrinsic pathway
Activated Clotting Time (ACT)
Partial Thromboplastin Time (PTT/aPTT)
which tests can be used to asses the common pathway
Activated Clotting Time (ACT)
Primary Thromboplastin Time (PTT/aPTT)
Prothrombin Time (PT)
which tests can be used to asses the extrinsic pathway
Prothrombin Time (PT)
why would a dog with decreased platelets but an increased MPV not have an issue with primary hemostasis
larger platelets are more hemostatically active
