Lecture 14: Blood Flashcards
(92 cards)
What initiates primary hemostasis in the coagulation cascade?
arterial vasoconstriction occurs to reduce blood flow to the site of the injury
What is involved in secondary hemostasis?
the two pathways: intrinsic and extrinsic
What is the intrinsic pathway in the coagulation cascade?
contact activation: the blood is exposed to the surface of the damaged endothelium and collagen within that wall and this contact activated factor XII to XIIa
What is the extrinsic pathway in the coagulation cascade?
traumatized tissue releases tissue factors which complex with factor VIIa
factory I
fibrinogen
factor II
prothrombin
factor III
tissue factor or thromboplastin
factor VIII
antihemophilic factor
factor IX
Christmas factor
What are the vitamin K dependent clotting factors?
II, VII, IX, and X
What is an good indication of the presence of an inherited bleeding disorder?
bleeding after minor surgical procedures especially dental procedures
What is the percent of patients with hemophilia A or B that have a negative family history?
30-40%
What are the indications of a platelet defect?
mucocutaneous bleeding after cuts, increased bleeding after cuts, small areas of superficial bleeding after cuts, variable amounts of bleeding after major surgery
What are the indications of clotting factor deficiencies?
deep tissue bleeding (joint and muscle), large hematomas, can be delayed bleeding post-surgery
What are examples of platelet disorders?
Von Willebrand disease is most common, immune thrombocytopenia
What are examples of clotting deficiencies?
factor VIII (hemophilia A), factor IX (hemophilia B), factor XI (hemophilia C)
What is a hyppercoagulable disorder?
usually results in higher than normal risk for thrombosis formation; also knows as thrombophilia or bleeding diathesis; increased risk involved in pregnancy, cancer, and estrogen therapy
What is antithrombin III?
also known as antithrombin; is an alpha-2 globulin made in the liver; it is an anticoagulant
What happens in the absence of antithrombin III?
coagulation is constant, unchecked and eventually results in depletion of clotting factors -> leading to uncontrolled bleeding
How is antithrombin involved in mediating the balance of clotting and bleeding?
inactivation of thrombin, and inactivation of factor X to Xa
What is an antithrombin III lab test used for?
used to monitor for hyppercoagulable states
What can a decreased antithrombin result in?
deep vein thrombosis, pulmonary embolism, phlebitis, heparin resistance, early age onset of thromboembolic events
What are protein C and protein S?
they are anticoagulants that are synthesized in the liver; protein s is a co-factor to protein c that enhances the function of protein C
What does protein C inhibit?
factor Va and factor VIIIa