{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Dicumarol inhibition of vit k dependent factors

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: onents in blood & trauma to blood or exposure to collagen (or foreign surface) To trigger clot fiber net that traps RBCs PGG2 - PGH2 = plug PG12 - no plug (bleed) Anticoagulants vs Lysis of clots •  Anticoagulants –  prevents clots from forming •  chelators-tye up calcium (citrate, oxylate) •  heparin- complexes with Antithrobin III •  dicumarol-inhibition of Vit. K dependent factors –  factors II, VII, IX, X (synthesized by hepatocytes Activators of Plasminogen •  Endogenous Activators –  tissues –  plasma –  urine •  Exogenous Activators –  streptokinase –  tPA (tissue plasminogen activator) TPA - used to clear clots immediately after strokes •  Lysis of Clots –  Plasmin (from plasminogen) Plasmin breaks down fibrin into fibrin split Aspirin & Ibuprofen •  Block both thromboxane A2 & prostacyclin production by blocking fatty acid cyclooxygenase which converts arachidonic acid to PGG2 & PGH2 (intermediates) •  Why take aspirin to prevent heart attacks? Because it prevents clotting Reperfusion injury •  Most of the frank tissue damage associated with infarction occurs upon reperfusion •  associated with the formation of highly reactive oxygen species with unpaired electrons. free radicals •  When pressure on tissues relieved & again perfused with blood, free radicals are generated (this when frank damage occurs) Free radicals - rip electrons from tissue to become stratified Reperfusion of tissue causes damage - not ischemia of it bc of production of ROS 3 Collateralization •  The ability to open up alternate routes of blood flow to compensate for a blocked vessel –  Angiogenesis Ability to form new vessels –  Vasodilatation Enlarging blood vessels –  Role of the SNS ?? •  May impede Cx of bv •  May augment Neuropeptide Y Protective mechanism Blood Coagulation- Thrombosis •  Extrinsic mechanism-initiated by chemical factors released by damaged tissues •  Intrinsic mechanism-requires only components in blood & trauma to blood or exposure to collagen (or foreign surface) Clotting factors •  •  •  •  •  •  •  I- fibrinogen II- Prothrombin III- Thromboplastin IV- Calcium V- Proaccelerin VII- Serum prothombin conversion acclerator VIII- antihemophilic factor (A) Clotting factors (cont.) •  IX- antihemophilic factor B christmas factor •  X- Stuart factor •  XI- antihemophilic factor C •  XII- Hageman factor •  XIII- Fibrin-stabilizing factor •  Prekallikrein- Fletcher factor •  High molecular weight kininogen •  Platelets Sex linked on x chromosome Hepatocytes role in clotting •  Liver synthesizes 5 clotting factors –  I (fibrinogen) –  II (prothrombin) –  VII (SPCA) –  IX (AHF B) –  X (Stuart factor) Hemophilia •  Sex linked on X chromosome –  occurs almost exclusively in males –  85% of cases- defect in factor VIII –  15% of cases- defect in factor IX •  varying degree of severity from mild ⇒ severe <5% - defect i n factor XI •  Coumarin (warfarin or cumadin) depresses liver formation of II, VII, IX, X by blocking action of vitamin K 4 Ca required for steps 3- the end Blood Coagulation •  The key step is the conversion of fibrinogen to fibrin which requires thrombin »  thrombin Intrinsic pathway •  Factor XII activated when blood contacts a negatively charged surface (collagen, glass) •  Activated XII + Kalikrein+ Kinnogen will activate Factor XI •  Activated XI + Ca++ will activate both Factors IX & VIII •  Activated IX + VIII + Phospholipid + Ca++ will activate Factors X & V •  Activated X + V + Pho...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern