Flashcards in Platelet Function Deck (12):
What are the 3 steps for the formation of a platelet plug?
1. Platelet Adhesion
2. Platelet Activation
3. Platelet Aggregation
Describe the process of platelet adhesion.
endothelial damage--release of:
PGI2, tpA, vWF, thromboplastin (tissue factor)
vWF binds exposed collagen.
platelets bind vWF via Gp1b receptor
Describe the process of platelet activation?
after platelets adhere, they change conformation and form pseudopods that help them bind tightly to site of injury
secrete substances: fibrinogen, thrombin, thromboxane A2, ADP, PDGF, serotonin, lysosomal enzymes, vWF
Describe the process of platelet aggregation.
released ADP from platelets that are activated is attached to platelet receptor. Then Gp2b3a receptor pops up on platelet. This binds the fibrinogen that was released.
A bunch of platelets start aggregating by binding fibrinogen
vWF is linked by _____ bonds. IT is released from 2 things and has 2 functions and increases 2 lab values. What are they?
**Endothelial cells (weibel palade bodies)
**platelets alpha granules
***stabilizes Factor 8
**causes platelet adhesion
**increases bleeding time IF DEFICIENCY
Describe the contents of the 2 types of granules of platelets.
dense granules: ADP, Ca++ (important for coag)
alpha granules: vWF, fibrinogen
What is the MOA of aspirin?
irreversibly inhibits COX1,2
decreases thromboxane A2 production
No effect on PT or PTT
but b/c it is anti-platelet, increases bleeding time
What are the SE of aspirin?
gastric ulcers (COX1)
Reye syndrome in kids w/ viral infections: hepatoencephalopathy. Don't give to kids except Kawasaki
respiratory alkalosis via hyperventilation-->metabolic acidosis
What are the ADP receptor inhibitors?
What are the GP2b3a inhibitors?
Abciximab: monoclonal antibody fab fragment
What would you use to treat a STEMI? NSTEMI? If PCI was unavailable.
NSTEMI: anti-platelet therapy like GP2b3a inhibitor