the vestibular organs that detect horizontal or vertical linear movement of the head. (186)

The utricle and saccule are the otolith organs. They lie within the otic capsule on the medial wall of the vestibule. Each includes a membranous sac containing fluid ( endolymph). Within each sac is a macula, a flat membrane that projects sensory hair cells to its overlying otolithic membrane. The otolith organs are "mechanoreceptors," which are organic transducers made up of a neural and a mechanical portion. They are normally responsive to gravitation and other linear acceleration forces. If they become abnormally responsive to sound and/or pressure ( irritative focus); the result is vertigo and/or imbalance. Otolithic endorgan The sensory organ of the ear that is receptive to inertia and gravity(both of which are expressions of linear acceleration). Otolithic membrane Gelatinous membrane in the utricle and saccule in which are imbedded the otoconia ( otoliths).