臓器（ぞうき）   viscera, internal organs

臓物（ぞうもつ）   entrails, giblets

内臓（ないぞう）   internal organs, intestines

心臓（しんぞう）   heart

肝臓（かんぞう）   liver

腎臓（じんぞう）   kidney

五臓六腑（ごぞうろっぷ）   the internal organs