Clotting and Bleeding Disorders Lecture Powerpoint Flashcards
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Bleeding disorders are also sometimes known as….
….coagulopathies
Phases of clot formation and a brief explanation according to Pam (4)
1) vascular injury and spasm - constriction of injured vessel
2) platelet plug formation - von Willebrand factor needed to bridge platelets and collagen
3) Coagulation cascade - intrinsic or extrinsic fibrin formation
4) dissolution of clot
Tunica media compliance
Decreases as we age causing greater shear from blood flow such as with atherosclerosis
What 2 cells synthesize vonWillebrand factor?
Platelets
Endothelial cells
In a resting state, an endothelial cell is a vaso____ and ____ platelet adhesion
dilator, inhibits
Serotonin is a vaso____, although we often only think of its psychological properties
constrictor
What 3 organs produce thrombopoietin?
Liver
Bone marrow
Kidney
ASA causes ___ binding of a platelet acting for ___ to ___ days
irreversible, 7-10 or the life of the thrombocyte
4 major functions of platelets
1) adhesion/activation
2) aggregation
3) secretion
4) procoagulant activation
4 steps of platelet action mech of action
- platelet binds to subendothelial matrix von willebrand factor activating glycoprotein iib/iiia surface receptors
- Platelets cohere and aggregate and fibrinogen binds activated glycoprotein 2b/3a becoming fibrin
- Platelet granule proteins such as ADO, serotonin, factor V, and thromboxane are released
- Fibrin activates thrombin via the clotting cascade
Von Willebrand factor
An adherent glycoprotein on the sub endothelial matrix that allows for activation of glycoprotein IIb/IIIa surface receptors on thrombocytes to begin adhering to the surface
The most common herreditary bleeding disorder is….
…von wilibrand factor deficiency
Role of Ca2+ in clotting cascade
It acts as factor 4 in allowing fibrin to polymerize
Factor X
The convergent point between the extrinsic and intrinsic pathway that functions to convert prothrombin (factor II) to thrombin (factor IIa)
D dimer test function and why is it not sufficient?
Looks for breakdown of collagen chains indicating a clot has occurred in the body, but not specific as to where
The intrinsic clotting pathway is ___ than the extrinsic, the intrinsic involves ___ while extrinsic involves _____
Faster, factors in blood itself, tissue factor released from damaged vessels
Amplification cascade
Tendency for the clotting cascade to amplify its response from a small amount of starting factors
Where do the majority of clotting factors come from?
The liver
Intrinsic clotting cascade pathway
Surface contact activates factor XII to XIIa, which activates factor XI to XIa, which activates IX to IXa, which activates VIII and Ca2+ (factor IV) to convert factor X to Xa
Extrinsic clotting cascade pathway
Tissue damage activates Tissue factor (VII), which activates factor X to Xa
List the vit K dependent procoagulants
Factor II, VII, IX, and X
Protein C and S action
Inactivate factor Va and VIIIa acting as a natural anticoagulant
Protein C and S deficiency results in…
Spontaneous thrombosis, suspected genetic inheritance in young with DVT or stroke
Factor V leidan definition
Mutation in factor V that allows it to resist protein C, resulting in increased venous thromboembolism
