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17 Cards in this Set
- Front
- Back
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Aspirin
Action |
In order to undergo a release reaction, the production of prostaglandins by platelets is required
Aspirin inhibits the conversion of arachidonic acid into prostaglandins so the release reaction does not occur and there is no platelet plug formation |
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Von willebrand Factor
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Factor VIII (8)
2 different genetic diseases may be seen with defects in factor VIII Hemophilia A - defect prevents factor VIII from taking part in the intrinsic pathway von Willebrand's Disease - defect prevents platelets from sticking to collagen, so you can not form the platelet plug |
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Anticoagulants
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Prevent clotting
Citrate/EDTA Heparin Coumarin |
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Anticoagulants
Citrate/EDTA |
Chelates (binds) calcium
Therefore, less Ca++ are available for clotting |
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Anticoagulants
Heparin |
Activates a plasma protein called antithrombin III
Antithrombin III combines with and inactivates thrombin therefore, thrombin can't convert fibrinogen to fibrin Heparin works immediately |
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Anticoagulants
Coumarins |
Prevent blood clotting by competing with vitamin K
vitamin K is needed for the formation of factors II (2), VII (7), IX (9), and X (10), by the liver Coumarin needs several days to work; heparin works immediately |
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Fibrinolysis
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Dissolution of clot
Breaking up the fibrin Several factors are involved As the damaged blood vessel is repaired activated factor XII converts prekallikrein to kallikrein Kallikrein catalyzes the conversion of plasminogen into plasmin Plasmin is an enzyme that breaksdown fibrin Represents the completion of a delayed negative feedback loop since a clotting factor (XII) starts the dissolution of the clot |
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Plasminogen activators
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Used clinically to promote dissolution of clots
Kallikrein May be endogenous - produced by tissues and leukocytes; or exogenous - produced by bacteria Tissue plasminogen activator - endogenous Streptokinase - exogenous - widely used plasminogen activator These agents may be injected into a vessel that has become blocked (occluded) by a clot |
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Plasminogen Activators
Tissue Plasminogen Activator |
TPA
Made by genetic engineering Product of human genes introduced into bacteria Plasminogen activators are used in stroke patients - to break up clot that formed in the brain |
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Aspirin
Contraindicated |
Blood donors
Women ready to give birth - in last trimester of pregnancy Surgical candidates |
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Asprin
Beneficial |
Patients with atherosclerosis because oif clot formation
Patients with a history of heart attack (MI) or stroke (CVA) |
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Aspirin
Pathway |
Aspirin inhibits cyclooxygenase and therefore inhibits the conversion of arachidonic acid to prostaglandins
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Plasmacrit
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get
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Fluid compartments
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intracellular
Extracellular Interstitial (tissue) Plasma |
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Hematocrit
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get
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Clotting
Initial Stimulus |
Injured vessel
Collagen of vessel wall exposed to blood |
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Platelet Plug Formation
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Adhesion (stick)
Release reaction Aggregation |
