Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
48 Cards in this Set
- Front
- Back
|
what makes thromboxane A2
|
platelets (converts PGH2.. aspirin irreversibly inhibits PGH2)
|
|
|
actions of heparin like molecules
|
enhace antithrombin III
neutralized active serine proteases (XII, XI, IX, X, thrombin) |
|
|
what does prostaglandin I2 (prostacyclin do
|
it is a vasodilator and inhibits platelet aggregation. it is made by endothelial cells and NOT affected by aspirin
|
|
|
what do proteins C and S do?
|
inactivate factors v and Viii
|
|
|
what makes tissue plasminogen activator
|
endothelial cells
|
|
|
what is the action of tissue plasminogen activator?
|
activates plasminogen to plasmin ("clot buster"
|
|
|
what are the functions of thromboxane A2
|
vasoconstrictor
enhances platelet aggregation |
|
|
what makes von willibrand factor
|
endothelial cells and megakaryocytes
|
|
|
function of vWF?
|
platelet adhesion
binds platelets to exposed collagen |
|
|
what does VII:vWF do?
|
prevents degradation of VIII:C
|
|
|
what does tissue factor (tissue thromboplastin) activate?
|
factor Vii (extrinsic)
|
|
|
what makes platelets?
|
megakarocytes (1000-3000/megakaryoctye)
|
|
|
life of a platelet?
|
9-10 days
|
|
|
how much of platelets are stored in the spleen?
|
1/3
|
|
|
what platlet receptors bind vWF
|
GpIb
|
|
|
platelet receptors for fibrinogen
|
GpIIb:IIIa (expression reduced by ticlopidine and clopidogrel)
abciximab makes AB against gpIIb:IIIa |
|
|
platelet factor 3
|
located on platelet membrane-required for clotting sequence
|
|
|
Contents of platelet dense bodies
|
ADP (causes aggregation) Ca++ (binges vitamin K dependant factors)
|
|
|
contents of platelet alpha granules
|
vWF and fibrinogen
|
|
|
platelet factor 4
|
neutralizes heparin
|
|
|
function of platelets
|
fills gaps in endothelial cells preventing leakage of RBCS
makes hemostatic plug growth factors stimulates smooth muscle hyperplasia |
|
|
factors in instrinsic cascade
|
XII, XI, IX, and VIII
|
|
|
factors common to both pathways
|
X, II, I, Xiii (and maybe 9?)
|
|
|
what causes activation of factor VII (hageman factor)
|
tissue factor: exposed endothelial collagen, high molecular weight kininogen (HMWK)
|
|
|
function of factor XIIa
|
activates XI, plasminogen, kininogen systems
|
|
|
what does factor XIa activate?
|
IX which causes a complex of IXa, VIII, platelet factor 3 and calcium to form which activates V
|
|
|
factors in final common pathway
|
X, V, prothrombin (II), and fibrinogen (1)
|
|
|
functions of thrombin
|
acts of fibrinogen to fibrin, strengthens fibrin clot via cross linking
|
|
|
factors dependant on vitamin K
|
II, VII, IX, X, protein C and protein S
|
|
|
what enzyme is used for vitamin K synthesis and what inhibits it?
|
vitamin k is synthesized in the liver by epoxide reductase. Epoxide reductase is inhibits by warfarin
|
|
|
how long does it take to anticoagulate with warfarin
|
because previously carboxylated factors are still around (like prothrombin) it takes 3-4 days for full anticoagulation
|
|
|
is heparin anticoagulation quick or slow?
|
quick-acts almost immediately by increasing antithrombin III activity
|
|
|
What factors do a fibrin clot consume?
|
fibrinogen, V, VIII, and prothrombin II
|
|
|
HOw is serum different than plasma?
|
Serum is missing fibrinogen, prothrombin, factor V and factor VIII
|
|
|
how is fibrinolytic system activated?
|
tPA actives plasminogen causes the relase of plasmin
|
|
|
How is plasmin inactivated?
|
alpha 2 antiplasmin made by the liver
|
|
|
what does ADP do to platelets?
|
ADP release causes platelet aggregation in the lumen of a vessel
|
|
|
small vessel response to injury
|
vasocontrictions, Factor VII activation (by tissue thromboplastin factor III), and exposed collagen activates XII
|
|
|
what causes a stable platelet plug?
|
thrombin-> fibrinogen attaching to GpIIb/IIIa receptors causing fibrin monomers that are insoluble
|
|
|
what is a normal platelet count?
|
150,000-400,000
|
|
|
what is a normal bleeding time?
|
2-7 minutes
|
|
|
What are platelet aggregating agents?
|
ADP, epinephrine, collagen, and ristocetin
|
|
|
what is a test for vWF
|
ristocetin cofactor assay
|
|
|
coag tests
|
prothrombin time, inr, ptt
|
|
|
what does prothrombin time evaluate?
|
extrinsic system down to fibrin clot (VII, X, V, iI, and I)
|
|
|
what is normal pt times
|
11-15 seconds (pt is only lowered when a factor is 30-40% of normal)
|
|
|
use of PT
|
people who are taking warfarin for therapy and evaluation liver function (increased pt in severe liver dysfunction), factor VII deficiency
|
|
|
use of ptt
|
to follow heparin therapy
|
