Question

Define fibrinolysis and describe how it is activated.

Answer 1

• Fibrinolysis is a process of break down of fibrin within blood clots, which is an important step in wound healing. If fibrinolyis doesnot regulated  properly ,  it will lead to numerous different diseases.
• There are two types of fibrinolysis, primary and secondary fibrinolysis. Primary fibrinolysis occurs naturally and secondary fibrinolysis occurs due to an external cause such as medicine or a medical disorder.
• Fibrinolyis is controlled by various cofactors , inhibitors and receptors.Plasmin is the main protein that activates fibrinolysis.
• Plasmin is converted from plasminogen by tissue plasminogen activator (tPA) and urokinase plasminogen activator (up A).
• tPA is synthesized by endothelial cells, whereas uPA is synthesized by monocytes, macrophages, and urinary epithelium cells.
• Plasmin activates tPA and uPA, creating a positive feedback loop where the activation of plasminogen leads to more activation of plasminogen. Positive feedback loop is important in clearing blood clot .
• Dysregulation and faults with the fibrin/fibrinogen proteins can lead to a multitude of disorders relating to bleeding and clot formation. Dysfibrinogenemias are caused by rare autosomal dominant mutations in any one of the three fibrinogen polypeptide chains