M8-M9

• Hemostasis


  Natural process that stops blood loss when an injury occurs. This process slows and stops the flow of blood outside the blood vessels therefore initiating wound healing.
• Hemostasis


  • Prevents and stops bleeding
  • Helps keep blood within a damaged blood vessel
• Hemostasis


  1. Vascular spasm (vasoconstriction)

  2. Platelet plug formation

  3. Blood clotting (coagulation)
• Vascular Spasm


  The smooth muscle in blood vessel walls contracts immediately when blood vessel is injured. This response reduces blood loss for some time, while the other hemostatic mechanisms become active.
• Platelet Plug Formation


  1. Platelets encounter damaged blood vessel

  2. Platelets form a "platelet plug" to help close the gap in the broken blood vessel

  3. Key stages: platelet adhesion, platelet release reaction, platelet aggregation
• Blood Clotting (Coagulation)


  While inside the blood vessels our blood remains in liquid state. Once injury occurs and blood goes out of blood vessels it thickens and coagulate (gel-like)
• Anticoagulation = process of slowing down the normal blood clotting to prevent the formation of blood clots.

   

   Anticoagulant agents = a drug that slows down or prevent formation of blood clots.

  They inhibit the coagulation process by interfering with the clotting cascade and thrombin formation
• Purpose of Anticoagulant drug therapy:

  1. Prevents clot formation, BUT they DOES NOT dissolve existing clots
  2. Acts as prophylaxis to prevent new clots from forming
• What is thrombus?

  formation of clot in an arterial or venous vessel.
• What contributes to the development of thrombosis?

  "Virchow's Triad" are composed of three factors necessary for the formation of thrombosis:

  1. Endothelial injury
  2. Hypercoagubility
  3. Circulatory stasis