Stock Photo - <BR> <BR>Anatomy of the macula (organ of static balance). Located at the level of the inner ear, the macula is a thickening of the inner walls of the saccule and the utricle (see images 0228706 and 0228806). It is composed of hair cells (in orange), constitute the sensory receptors, and supporting cells (in pink). Each hair cell is possessed of 40 to 70 stereocilia (microvillosities) and a unique kinocila, cilium much longer. The supporting cells secrete a gelatinous substance forming the otolithic membrane, in which dig into the stereocilia and kinocilia. This membrane is recovered by a layer of aragonite cristals (calcium carbonate), the otoliths (in grey). Each hair cell forms a synapse with a sensitive neuron (in yellow) and a motor neuron (in green) of the vestibular nerve, branch of the auditory nerve. The mechanism of the macula is presented on the images 0228906 and 0229006.