Contact system is the beginning of intrinsic coagulation pathway and comprises four components : high molecular weight kininogen , prekallikrein , factor XII ( FXII ) and factor XI ( FXI ) .
内源性凝血途径的起始部分称为接触系统，包括高分子量激肽原、前激肽释放酶、XII因子和XI因子。
fxi