Hemostasis and Coagulation Flashcards
Mediators responsible for inhibition of platelet aggregation?
PGI2
NO
ADPase
Molecules that bind and inhibit thrombin
Heparin-like molecules (which accelerate anti-thrombin III inactivating thrombin)
Activity of thrombomodulin?
Activated Protein C, which leads to lysis of Factors 5 and 8
What does alpha 2 macroglobulin do?
Binds thrombin for removal from the circulation
Antithrombotic properties of resting endothelial cells (6)
- Inhib. platelet aggregation
- Binds+Inhibits thrombin
- Thrombomodulin
- Synth. protein S: cofactor for protein C
- alpha2 macroglobulin
- Fibrinolysis
Three prothrombotic properties of activated endothelium
- Endothelial cell injury leads to platelet aggregation/adhesion
- Activation of coagulation cascade
- Inhibition of fibrinolysis
How do activated ECs activate the coagulation cascade?
Tissue factor synthesis induced by cytokines or bacteria, which activates Factor 7
Three important actions of platelets upon activation
- Adhesion/Shape Change
- Secretion
- Aggregation
Platelet adhesion to the subendothelium requires _____ and _____ receptor
von Willebrand’s factor
GpIb receptors
What do platelets secrete?
Alpha Granules and Dense Bodies
What binding is important for platelets’ role in primary plug formation
GpIIb-IIIa and fibrinogen
Contents of Platelet alpha granules
fibrinogen, fibronectin, V, VIII, PF-4, PDGF, TGF-b
Contents of electron dense bodies
ADP, ATP, Ca, histamine, serotonin, epinephrine
Most important mediators of platelet aggregation
ADP
TxA2, thrombin
Intrinsic pathway is activated by ______ in vitro
Hageman Factor
Antithrombins inhibit…
Thrombin
AND
9a, 10a, 11a, 12a
Protein C and S inactivate…
5 and 8
Two types of plasminogen activators
Urokinase-like plasminogen activators
tissue-type plasminogen activators
When are urokinase-like plasminogen activators used
In fluid phase (serum/tissue)
When are tissue type plasminogen activators used?
Made by endothelium, activated when bound to fibrin
Decreased vW factor will also cause a lower level of….
8
