{HEAD ~ FXIIa} plays a very important role in the initiation stage in {TAIL ~ the intrinsic blood clotting system}, fibrinolysis system and plasma kallikrein kinin system 
{ HEAD ~ FXIIa } plays a very important role in the initiation stage in { TAIL ~ the intrinsic blood clotting system } , fibrinolysis system and plasma kallikrein kinin system
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH