hemostasis/coagulation Flashcards
3 major components to the hemostatic system
the vascular wall, platelets, and coagulation proteins
3 steps of the platelet response to vascular injury (primary hemostasis)
adhesion, activation, aggregation
platelet adhesion involves activation of a surface membrane receptor, _____, an adhesive protein, ____, and an appropriate surface, _____
glycoprotein Ib/IX
von Willebrand factor
subendothelial collagen
in fibrin clot formation (secondary hemostasis), soluble coagulation proteins within plasma are activated to generate ____ in an ____ reaction
thrombin; amplification
what does thrombin convert
thrombin converts fibrin to fibrinogen
fibrin adds ____ to the clot after fibrin monomers are covalently cross-linked by _____
stability; Factor XIII
sequence of the intrinsic pathway
activation of Factor XII by kallikrein
activation of Factor XI by Factor XIIa
Factor XIa activates Factor IX
sequence of extrinsic pathway
activation of Factor VII by tissue factor
sequence of the common pathway
activation of X to Xa
conversion of prothrombin (II) to thrombin
conversion of fibrinogen (I) to fibrin
regulatory systems in secondary hemostasis
serine protease inhibitors (antithrombins)
protein C pathway (controls Va and VIIIa)
fibrinolysis (removes excess clot)
antithrombins inhibit the activity of thrombin and other serine proteases (like ______) of the coagulation cascade by forming an inactive ______
factors IXa, Xa, XIa, and XIIa
enzyme-inhibitor complex
one of the best known antithrombins is _____, a molecule which, in the presence of _____, becomes activated so that it can form a complex with thrombin, thus destroying the ability of thrombin to participate in generation of _____
antithrombin III
heparin
fibrin monomers
protein C system regulates the major cofactors of the coagulation cascade, _____
factors Va and VIIIa
activated _____ is the major effector enzyme of the protein C system and ____ is a major cofactor
protein C; protein S
_____ promotes coagulation through resistance to enzymatic inactivation by the Protein C/S complex
Factor V Leiden mutation
in the presence of fibrin, _____ can bind to _____ and convert it to the activate enzyme which breaks down fibrin monomers into fibrin degradation products
tissue plasminogen activator (TPA) ; plasminogen (active enzyme = plasmin)
common lab screening tests used to evaluate hemostasis
prothrombin time (PT) international normalized ratio (INR) partial thromboplastin time (PTT) platelet count bleeding time
clinical manifestations of disorders of primary hemostasis include _____ and/or ______; laboratory manifestations include _____ and _____
mucocutaneous bleeding (petechial); bleeding associated with trauma prolonged bleeding time; thrombocytopenia
clinical manifestations of disorders of secondary hemostasis include _____ and/or _____; laboratory manifestations include a _____ and/or _____
soft tissue bleeding; bleeding associated with trauma
prolonged PT and/or PTT; thrombin time
clinical manifestations of disorders of the regulatory system include _____ and/or ______; laboratory manifestations are often ____ in screening tests
soft tissue bleeding; bleeding associated with trauma
normal
congenital disorders associated with bleeding
von willebrand disease hemophilia A (factor VIII deficiency) hemophilia B (factor IX deficiency)
two most frequent congenital bleeding disorders
von willebrand disease and hemophilia A
von willebrand disease is an _____ disorder associated with production of decreased amounts of a _____ (quantitative abnormality) or production of a protein with _____ (qualitative abnormality), or both
autosomal dominant; normal protein; abnormal function
predominant clinical manifestation of von willebrand disease is _____
mucocutaneous bleeding
