Factor XI, also known as plasma thromboplastin antecedent (PTA), is a protein that plays a crucial role in blood coagulation. It is one of the many clotting factors involved in the cascade of reactions that promote the formation of blood clots to stop bleeding.
Factor XI is produced in the liver and circulates in the blood in an inactive form. Upon injury or damage to blood vessels, it becomes activated and begins its role in the coagulation process. Activation of factor XI occurs through various triggers, including exposure to collagen, tissue factor, and activated platelets.
Once activated, factor XI initiates a chain reaction that leads to the production of thrombin, an enzyme that converts fibrinogen into fibrin. Fibrin forms a mesh-like network that helps in the formation of blood clots, preventing excessive bleeding. This process is crucial for hemostasis, the mechanism our body employs to maintain blood flow within a normal range.
Deficiencies in factor XI can lead to a bleeding disorder known as hemophilia C or Rosenthal syndrome, although the bleeding symptoms are generally milder compared to other forms of hemophilia. Treatment options for factor XI deficiencies include administration of factor XI concentrate or recombinant factor VIIa to restore normal clotting function.
In summary, factor XI is a coagulation factor responsible for initiating the clotting cascade, ultimately leading to the formation of blood clots to prevent excessive bleeding.
