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16 Cards in this Set
- Front
- Back
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What are the factors concerned with hemostasis? (abnormalities of blood coagulation) |
Integrity of small blood vessels Adequate numbers of platelets Normal amounts of coagulation factors Normal amounts of coagulation inhibitors Adequate amounts of calcium ions in the blood |
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What role does small vessels play in hemostasis? |
Small vessels are first line of defense in body, constrict on injury to facilitate closure by clot, exposure of underlying connective tissue of endothelium causes platelet adhesion and activates coagulation mechanism. |
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Whatthree functions do platelets play in hemostasis? |
Plug defect in vessel wall liberate vasoconstrictors and compounds causing platelets to aggregate release substances that initiate coagulation |
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Whatare the three phases of blood coagulation? What happens in each phase? |
Phase 1- prothrombin activator generated. intrinsic system-components derived from blood extrinsic system- tissue injury yields tissue thromboplastin Phase 2- conversion of prothrombin into thrombin Phase 3- Conversion of fibrinogen into fibrin by thrombin |
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Whatroles do coagulation inhibitors, antithrombin, and plasmin in regulating blood coagulation? |
Coagulation inhibitors- coagulations factors counterbalanced by coagulation inhibitors. Restrict clotting process to limited area Antithrombin- inhibits thrombin, inhibits other activated coagulation factors generated in clotting process Plasmin- important control system dissolves fibrin after formed, plasminogen activated to form plasmin (fibrinolysin), fibrinolytic system activated at same time coagulation process initiated |
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Whatare the four classes of disturbances of blood coagulation? What causes each class? |
1. Abnormality of small blood vessels- abnormal bleeding resulting from failure of small blood vessels to contract after tissue injury, abnormality of blood vessel formation 2. abnormality of platelet formation 3. Deficiency of one or more plasma coagulation factors 4. Liberation of thromboplastic material into circulation |
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Whatis thrombocytopenia and what are somecauses? |
Thrombocytopenia- platelet deficiency. injury or disease of bone marrow damaging the megakaryocytes, infiltration of bone marrow by leukemic cells or cancer cells, crowding out the megakaryocytes, anti platelet antibodies destroy platelets in peripheral blood, abnormal function of platelets despite normal count |
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Whatare petechiae and what causes them? |
Small red or red-blue spots about 1-5mm Pinpoint-sized hemorrhages of small capillaries in skin or mucous membranes Indicative of defective or inadequate platelets or a capillary defect |
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Whatare some causes of disturbances of phase 1 and phase 2 of the blood coagulationcascade? What are some signs andsymptoms that were discussed? |
Phase 1- usually hereditary; relatively rare except: hemophilia- ~ con Willebrand disease Phase 2- deficiency of prothrombin or factors required for the conversion of prothrombin into thrombin |
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Whatare some causes of thromboplastin being released into the circulation? |
- Diseases associated with shock and tissue necrosis - Overwhelming bacterial infections - Other causes of tissue necrosis |
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What is disseminated intravascularcoagulation syndrome? What are somesigns and symptoms? |
Thromboplastic substances are liberated into the circulation Signs/Symptoms- clotting, activation of fibbrinolytic system to defend body from widespread intravascular clotting. Clots are dissolved to prevent lethal obstruction of the circulatory system. End result is abnormal bleeding state |
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Hemostasis |
Arrest of bleeding caused by activation of blood coagulation mechanism |
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Blood Coagulation Process |
Highly complex chain reaction |
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Hemophilia |
-x-linked hereditary disease affecting males -episodes of hemorrhage inn joints and internal organs after minor injury Hemophilia A-Classic=Factor VIII (antihemophilic factor) Hemophilia B- Christmas Disease (after affected patient)= Factor IX (christmas factor) |
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von Willebrand Disease |
:Von Willebrand factor -autosomal dominant disease -large protein molecule produced by endothelial cells required for platelets to adhere to vessel wall at site of injury - vWF adheres to damaged vessel wall, forms framework allows platelets and coagulation factors to adhere, interact and form a clot |
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Release of Thromboplastic Material into Circulation |
1. diseases associated with shock and tissue necrosis 2. overwhelming bacterial infections 3. tissue necrosis All of those have thrombplastic activity, liberated into circulation, result in intravascular coagulation |
