The 'blood relationship' was not a 'house' but a blood relationship of a wife and husband, parent and child as well as grandchild, and was referred often as 'ie' (currently defined as house) or 'miuchi' (currently defined as close relatives).
そこでの「血縁」は、「家」ではなく、嫁と夫、親と子・孫という血縁であって、よく「イエ」と「ミウチ」という言い方をされる。