part_of part of part of anatomical system vestibular labyrinth otolith organ http://upload.wikimedia.org/wikipedia/commons/c/cb/Bigotolith.jpg GAID:883 VHOG:0001676 TAO:0000559 EFO:0003539 otolith organs UBERON:0002518 Wikipedia:Otolith_organ In fishes, as in other vertebrates, the vestibular end-organs are divided into a gravity receptor system, with three subdivisions and an angular acceleration receptor system. The gravity receptor system on each side consists of utricular, saccular, and lagenar maculae, each covered by an otolith (reference 1); (...)considerations have led to our rethinking issues related to the origin of several aspects of vertebrate hearing, and to the view that many basic auditory functions evolved very early in vertebrate history, and that the functions observed in more `advanced' vertebrates, such as birds and mammals, are frequently modifications of themes first encountered in fishes, and perhaps even more ancestral animals (reference 2).[well established][VHOG] saccule and utricle MA:0002841 ZFA:0000559 The crystalline particles composed of calcium carbonate and a protein which adhere to the gelatinous membrane of the maculae of the utricle and saccule (otolithic membrane). MESH:D012444 Representation of utricle, sacule and otoliths in correspondence to other ontologies may require review. In EHDAA2, saccule and utricle are epithelia utricle and saccule zebrafish component