281b - platelet fxn Flashcards Preview

heme/onc > 281b - platelet fxn > Flashcards

Flashcards in 281b - platelet fxn Deck (13):
1

where does thrombin generation occur? how?

surface of platelets

scramblase --> negative PL on outer lipid membrane --> factors and Ca assemble

2

signs of platelet defects?

easy bruising, petechiae

mucus bleeding

3

what controls proplatelet formations in MK?

microtubules w/ motors --> extended from BM into vessel sinuses

4

platelet lifespan

10 days --> apoptosis

consumed earlier in normal endo fxn too

5

granules

released when platelets activated and change shape

dense = ADP, Ca (Small molecules)

alpha = fibrinogen, vWF (proteins)

5

ITP

immune thrombocytopenia - autoimmune disorder

abs --> GPIIb/IIIa

5

what do normal endothelial cells have for antiplatelet activity?

NO
PGI2
ecto-ADPase (CD39) on surface

5

what do platelets binds on damaged endothelium?

collagen via vWF - GPIb --> rolling

fibrinogen receptors - GPIIb/IIIa --> aggregation

5

hereditary defects of platelet fxn?

bernard-soulier syndrome = GPib + very large platelets

Glanzmann thrombasthenia = GPIIbIIIa

6

platelet fxn disorders - acquired

drugs (ASA, NASIDS)
uremia
dysporteinemia (high IgA)
myeloproliferative disorders
CV bypass -> exhuastion from abnormal surface
Abs

6

hereditary defects of platelet fxn

bernard-soulier syndrome = GPib
Glansmann thrombasthenai = GPIIbIIIa

6

phospholipase A2 fxn in platelets?

converts PL from membrane --> TxA2 --> platelet agonist --> aggregation

6

what molecules recruit platelets?

ADP
TxA2
fibrinogen