COAGULATION PROCESS

• Coagulation


  Also known as clotting, the process by which blood changes from a liquid to a gel, forming a blood clot
• Coagulation


  • Potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair
• Coagulation factors


  Proteins in the blood that help control bleeding
• Coagulation process


  1. When a person gets a cut or other injury that causes bleeding, the coagulation factors work together to form a blood clot

  2. The clot stops a person from losing too much blood
• 12 coagulation factors involved in the coagulation cascade


  • Fibrinogen
  • Prothrombin
  • Tissue factor or thromboplastin
  • Calcium
  • Proaccelerin (labile factor)
  • Proconvertin (stable factor)
  • Antihemophilic factor A/ Antihemophilic globulin
  • Antihemophilic factor B/ Plasma thromboplastin component/ Christmas factor
  • Stuart – Prower factor
  • Plasma thromboplastin antecedent/ Hemophilia C/ Rosenthal syndrome
  • Hageman factor
  • Fibrin – stabilizing factor, Laki – Lorand factor
• Hemostasis


  The process of slowing and stopping the flow of blood
• Hemostasis


  1. Vascular spasm or vasoconstriction

  2. Formation of a platelet plug

  3. Blood clotting or coagulation which reinforces the platelet plug with fibrin mesh that acts as a glue to hold the clot
• Intrinsic pathway


  The intrinsic pathway (contact activation pathway) occurs during exposure to negatively charged molecules, such as molecules on bacteria and various types of liquids
• Intrinsic pathway


  1. Begins with formation of a primary complex or collagen by high – molecular weight kininogen, prekallikrein and factors XII

  2. Factor XII is activated, which then activates factors XI, which activated factors IX, which along with factor VIII activates factor X in the common pathway
• Extrinsic pathway


  The main role of the extrinsic (tissue factor) pathway is to generate a "thrombin burst", a process by which large amounts of thrombin, the final component that cleaves fibrinogen to fibrin, is released instantly
• Extrinsic pathway


  1. Occurs during tissue damage when damaged cells release tissue factor III

  2. Tissue factor III acts on tissue factor VII in circulation and feeds into the final step of the common pathway, in which factor X cause thrombin to be created from prothrombin
• Common pathway


  In the final common pathway, prothrombin is converted to thrombin
• Common pathway


  1. When factor X is activated by either the intrinsic or extrinsic pathways, it activates prothrombin and converts it into thrombin using factors V

  2. Thrombin cleaves fibrinogen into fibrin, which forms the mesh that binds to and strengthens the platelet plug, finishing coagulation and thus hemostasis

  3. Thrombin also activates more factor V which later acts as an anticoagulant with inhibitor protein C, and factor XIII, which covalently bonds to fibrin to strengthen its attachment to the platelets
• Vitamin K is an essential factor of the coagulation cascade, it is involved in the synthesis of many factors of the coagulation cascade