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BC platelet plug #28.txt
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What is hemostasis?
no bleeding
What are the two parts of a thrombus?
platelet plug
fibrin clot
What are the three events of a vascular injury?
1) vasoconstriction
2) Platelet plug
3) fibrin clot
What is the difference b/t thrombocytopenia and thrombocytosis?
-cytopenia:
not enough platelets
-cytosis:
too many plateles
What are the three granule types in platelets?
Dense granules
: ADP and Ca
Alpha granules
: vWF, fibrinogen, serotonin, PDGF
Dense tubular system
: Ca
What prostanoid is active in healthy individuals and what is its function?
PGI
2
: inhibits platelet formation
How does PGI
2
function to stop platelet formation?
binds G
s
= cAMP
cAMP activate dense tubular system
dense tubular system uptakes Ca
Less intracellular Ca = less platelet plug formation
What does shear force to to vWF-collagen binding?
Increases (happens in people with thrombi or hypertension)
What are the five steps of platelet plug formation?
1) Adhesion
2) Activation
3) degranulation/secretion
4) shape change
5) aggregation
What is the most potent agonist of platelet activation?
Thrombi
What G protein is used for activation?
G
q
What is the function of ADP and is it Autocrine or Paracrine?
Increase platelet-aggregation
Autocrine
What is function of Plavix?
Inhibit ADP binding to its Autocrine receptor so platelet-aggregation is inhibited
What are the three important protein changes during the Shape Change?
1) GpIIa/IIIb
2) Phosphatidylserine flips out = more negative
3) negativity attracts VIIIa and Va = help with fibrin clot
What does GpIIIa/IIIb bind?
Fibrinogen that was secreted from Alpha granules
What is the binding site on fibrinogen?
RGD motif
What is the function of
integrilin
?
Inhibit binding of fibrinogen to GpIIa/IIIb by competing with fibrinogen
inhibit platelet aggregation
gWhich COX can recover after usage of low-dose aspirin and why?
COX-2 due to a nucleus
Author
kepling
ID
65371
Card Set
BC platelet plug #28.txt
Description
BC platelet plug #28
Updated
2011-02-16T00:43:15Z
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