Figure 1: The mechanism behind the coagulation factor XII (Hageman factor). Activation of factor XII and its direct and indirect effects may be mediated through multiple physiological pathways. FXII; factor XII, FXIIa; activated factor XII, βFXIIa; beta fragment FXIIa, FXI; factor XI, FXIa; activated factor XI, PK; plasma prekallikrein, K; kallikrein, HK; High molecular weight kininogen, HKa; cleaved HK, BK; bradykinin, tPA; tissue plasminogen activator, and BP; blood pressure.