Vestibular System: Overview
The vestibular system is our sixth sense. Not only does it contribute to our sense of orientation and movement in space but, via the vestibulo-ocular reflex (VOR), it stabilizes our vision, especially during rapid unpredictable head movements. Without the VOR our visual world would appear to move every time we undertook an activity that involves head movement, such as during walking, running, climbing, or driving on a bumpy road.
The vestibular organ is located in the inner ear next to the cochlear. As our head movements consist of rotations (nodding in affirmation) and translations (jumping up and down when happy), the vestibular organ comprises two sensor systems. The semicircular canals sense angular head rotations while the otolith organs sense linear head translations (See Vestibular Otoliths, Response to Vibration and Sound). Both the semicircular canals and otolith organs rely on specialized hair cells and the inertia of fluid (canals) or a gelatinous mass...