intrinsic pathway
Intrinsic Pathway The intrinsic pathway also known as the contact activation pathway is longer and more complex. In this case, the factors involved are intrinsic to present within the bloodstream. The pathway can be prompted by damage to the tissues, resulting from internal factors such as arterial disease; however, it is most often initiated when factor XII Hageman factor comes into contact with foreign materials, such as when a blood sample is put into a glass test tube. Within the body, factor XII is typically activated when it encounters negatively charged molecules, such as inorganic polymers and phosphate produced earlier in the series of intrinsic pathway reactions. Factor XII sets off a series of reactions that in turn activates factor XI antihemolytic factor C or plasma thromboplastin antecedent then factor IX antihemolytic factor B or plasma thromboplasmin . In the meantime, chemicals released by the platelets increase the rate of these activation reactions. Finally, factor VIII antihemolytic factor A from the platelets and endothelial cells combines with factor IX antihemolytic factor B or plasma thromboplasmin to form an enzyme complex that activates factor X StuartPrower factor or thrombokinase , leading to the common pathway. The events in the intrinsic pathway are completed in a few minutes.