As the sequential activation of
factors proceeds into the common pathway, the powerful enzyme thrombin
is generated. This key enzyme
splits fibrinogen into fibrin, the
substance that ultimately becomes a
stable fibrin clot.
During clot formation, thrombin
and other activated factors initiate
fibrinolysis.4 Fibrinolysis eventually
breaks down clots after the torn vessels
are healed and allows blood flow
to be reestablished (Figure 4). This
breakdown involves activation of
natural tissue plasminogen activator.