Term
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Definition
-platelet plug formation
-damaged endothelial cells interact with platelets via von Willebrand's factor |
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Term
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Definition
-large glycoprtn
-mediates platelet adhesion to exposed extracellular matrix when the endothelial lining of the blood vessel is damaged (in plasma and extracellular matrix)
-adhered platelets become activated by agents (thrombin and thromboxane) increased the calcium concentration of platelet |
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Term
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Definition
-Formation of cross-linked fibrin clot through a series of proteolytically activated enzymes (clotting factors)
-initiated by activated platelets and factors released from dammed tissue
-takes place on surface of aggregated, activated platelets (initially and most efficiently) |
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Term
| 4 Major players of clot formation: |
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Definition
1. Endothelial Cells: (inhibit blood clotting, produce prostacyclin which is an inhibitor of platelet adhesion and aggregation b/c when endothelium is in tact, don't want clot formation)
2. Subendothelial Tissue: (not normally exposed or in contact w/blood, platelets and clotting factors bind to this tissue)
3. Platelets: (release protons and vasoactive amines after binding to the subendothelial tissue, clotting Factors before active on the surface of these activated platelets
4. CF: (plasma protons which create a protelolytic cascade which ends with the production of insoluble fibrin from soluble fibrinogen) |
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Term
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Definition
-aggregation of platelets alone isn't enough to seal large injury
-fibrin is not normally found in blood but its precursor (fibrinogen) is present and when cleaved by protease thrombin = fibrin |
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Term
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Definition
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Term
| Cross linking is catalyzed by: |
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Definition
| Transglutaminase, Factor 13 |
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Term
| Thrombin & Where VIT K enters |
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Definition
-formation lmtd to side to injury.
-activated from prothrombin from Factor Xa
-rxn = thrombin and inactive fragment
-inactive fragment contains 10 residues of gamma-carboxyglutamate (these are produced by hepatocytes by a rxn req VIT K) |
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Term
| Can factor X be activated by intrinsic and extrinsic pathways? |
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Definition
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Term
| Extrinsic pathway has 1 factor... |
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Definition
| Factor VIIa (active only in presence of tissue factor, a membrane glycoprtn exposed after injury of blood vessel) |
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Term
| Does the intrinsic pathway req a (+) charged surface to activate? |
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Definition
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Term
| CLassic example of extrinsic pathway? |
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Definition
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Term
| Not a gross vascular damage from outside, might be a microtear or plaque causing issues, what is it? |
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Definition
| example of intrinsic pathway |
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Term
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Definition
*initiating rxn of the intrinsic pathway
-REQ 2 proteases: 1. kallikrein and 2. factor XIIa
-also REQ
FINISH |
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Term
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Definition
prothrombin-->thrombin
x-->xa
IX--IXa
more?? |
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Term
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Definition
*most IMP inhibitor of clotting
*activated by heparin
*most proteases of the intrinsic and extrinsic pathways are inhibited by ATIII and heparin |
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Term
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Definition
-degrades fibrin clot
-from inactive precursor plasminogen which binds fibrin clot with high affinity
-fibrin complex can be activated by tissue type plasminogen activator (tPA)
* a serine protease that also binds to fibrin
FINISH |
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Term
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Definition
tPA
1. urokinase
2. streptokinase (activates allosterically without proteolytic cleavage)
*with acute MI within an hour |
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Term
| Clotting can be inhibited by removal of what ions? |
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Definition
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Term
| Which factors are Vit K dependent? |
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Definition
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Term
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Definition
1. bleeding time
2. aPTT
3. PT |
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Term
| What test measure heparin and coumadin efficacy? |
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Definition
aPTT will be used to measure the efficacy of heparin (intrinsic and common)
PT measure the efficacy of coumadin (extrinsic and common) |
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