part of part of primary circulatory organ dorsal vessel heart FBbt has two terms that are both narrower than this, for adult heart, and embryonic/larval heart. heart The caudal, pulsatile region of the dorsal vessel of the arthropod circulatory system. SPD:0000130 UBERON:0015230 adult heart FBbt:00003154 embryonic/larval heart circulatory system dorsal vessel