hemostasis Flashcards
what cells produce von willebrand factor
endothelial cells when they are damaged it is exposed
what binds the platelets to von willebrand
Gp1b very tight binding helps it withstand sheer force of the flowing blood.
what else does von willebrand bind what clotting factor
Factor 8 this will improve the half life of the factor
what on platelets binds collagen at the site of damage
a2b1 bind the platelet to the ecm
what causes the shape change in the platelets
adhesion triggers release of Ca2+ that causes the shape change
what does a dense granule from an activate platelet contain
ADP ATP Ca2+ histamine serotonin epinephrin
what dose an alpha granule from an active platelet contain
fibrinogen fibronectin vWF coagulation factor 5 and PDGF
what else does an activated platelet release
arachidonic acid that gets converted by COX to thromboxane A2
what of the stuff that is released by platelets leads to vasoconstriction
thromboxane A2, serotonin epinephrin.
what are signals for platelet aggregation
ADP and thromboxane A2
what is a change triggered by ADP
conformation of Gp2b and Gp3a allows reception of fibrinogen
what is the most common bleeding or clotting disorder
von Willebrand disease type 1 most common 80% are type 1
tell me about Von willebrand disease
does not bind factor 8 so it will have a shorter half life treated with desmopressin
what is bernard soulier syndrome
giant platelets often thrombocytopenia, fail to aggregate, defect in interaction of vWF and Gp1b so we give platelet transfusion when bleeding occurs or will occur
what is glanzmann thrombasthenia
defective gP2b and/or gP3a , fail to aggregate therapy platelet transfusion to address bleeding
what causes the intrinsic pathway to start
negative charged surface like glass. Leads to the test partial thromboplastin time test
what causes the extrinsic pathway to start
tissue factor , leads to the test prothrombin time test
name factors 1-4
fibrinogen, prothrombin, tissue factor, and Ca2+
what factors contain carbocyglutamate and why
7 9 and 10. function to chelate ca2+ when bound to Ca2+ it makes the clot formation restricted to site of injury all require vit K
what was the original developed for warfarin
rodenticide
what is the most important pathway
extrinsic
tell me about the steps to the extrinsic pathway
7 binds tissue factor, then binds 10, this will slowly activate thrombin from prothrombin and will activate factor5. Then 10a and 5a will complex with Ca2+ and this quickly activates prothrombin to thrombin.
what is the key regulator of hemostasis
thrombin actiavtes fibrinogen, factors 5,7,and 8
tell me about the intrinsic pathway
surface of endothelais cells, 11 and prekallikein in blood with kinogen will assemble, then carboxypeptidase clease prekallikrein,this will activate 12 which activaates 11 which activates 9 slowly, which actiaves thrombin which activates 8 and that rapidly acivates 10 .
tell me about the common pathway
Factor 10 activates thombin activates 13 makes the clot hard by makding bonds between lysine and glutamine using transglutaminase
what is hemophilia a and b
a most common deficiency in factor 8 B is a deficiency in factor 9, queen victoria had B
what are some endogenous anti-coagulates activates
Thrombin , protein c and protein S , serpins and tissue factor pathway inhibitor
tell me about thrombin protein c and s
thrombomodulin present in intact endothelial cell membrans when bound to thrombin will activae protien c and this will bind to protein s and form a complex that will degrade factor 8a and 5a
what is factor V leiden
mutation in factor 5 ressistant oe cleavage by protein C causes hypercoagulation
tell me about serpins
serine protease inhibitors binds heparin
tell me about tissue factor pathway inhibitor or TFPI
made by endotheisial clls, inhibits factor 7a and blocks the extrinsic pathway also inhibits 10a
tell me about fibrinolysis
plaminogen will bind fibrin activated by tPA this is released by activated protein c causes clot degradation
what inhibits tPA
Alpha 2 antiplasmin and alpha2 macroglobulin
what is streptokinase
produced b beta-hemolytic strptococci is an exogenous activator of plasminogen used to treat pulmonary embolism and DVT
