Flashcards in Hemostasis and Thrombosis Deck (31):
What is hemostasis?
process of blood clotting at the site of vascular injury
What is a hemorrhagic disorder?
too little clotting
What is a thrombotic disorder?
too much clotting
What are the main cells involved in hemostasis?
platelets and endothelium
What are the humoral factors involved in hemostasis?
plasma proteins and cellular contents
What is the difference in function between primary and secondary hemostasis?
primary: makes platelet plug
secondary: platelet plug made stronger with fibrin mesh addition
List the main steps in hemostasis.
vasoconstriction > primary hemostasis > secondary hemostasis > thrombus and antithrombotic events
What factor binds platelets to the site of injury?
von Willebrand factor
What protein allows platelets to interact with vW factor?
glycoprotein 1B (GpIb)
What protein facilitates platelet aggregation?
glycoprotein 2b3a complex (GpIIb-IIIa)
What are the main steps of primary hemostasis?
1. platelet adhesion (vW factor)
2. shape change
3. granule release (ADP, TxA2)
5. aggregation (hemostatic plug)
What are the two types of laboratory secondary hemostasis?
What coagulation factors are associated with the intrinsic secondary pathway?
XII, XI, IX, VIII
What coagulation factors are associated with the extrinsic secondary pathway?
VII, tissue factor
What coagulation factors are common between the intrinsic and extrinsic pathways?
X, V, II (prothrombin), I (fibrinogen)
Which ion immobilizes factors to the surface of the platelet plug?
What factors does thrombin upregulate?
XI, VIIIa, Va
What coagulation factors are used in vivo during secondary hemostasis?
tissue factor, VII, IX, X, VIII, XI, X, V, II (prothrombin), I (fibrinogen)
What stops the formation of the fibrin clot?
What enzyme cleaves fibrin into fibrin degradation products?
What circulating protein precipitates plasmin?
plasminogen (inactivated form)
What prevents excessive fibrin degradation?
binding of free plasmin to alpha2 antiplasmin
Which enzymes positively affect the fibrinolysis system?
tissue plasminogen activator (tPA) and urokinase
Which enzymes negatively affect fibrinolysis?
plasminogen activator inhibitors (PAI)
Which natural anticoagulant process inactivates thrombin?
antithrombin III + heparin like molecules
How are factors Va and VIIIa inactivated?
with a combo of protein C and S
What compounds released from endothelial cells inhibit platelet aggregation?
PGI2, NO, and adenosine diphosphatase
What tests primary hemostasis?
What tests the intrinsic pathway?
What tests the extrinsic pathway?