Balance / Vestibular system components
Components of the Vestibular System
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two components:
- SEMICIRCULAR CANALS: motion detectors
- lesions induce the sensation of SPINNING
- OTOLITH ORGANS (utricle and saccule): gravity detectors
- lesions induce the sensation of TILT
- SEMICIRCULAR CANALS: motion detectors
- vestibular system is involved in balance and posture, co-ordination of head and body movements and in fixating the visual image on the fovea (esp. VOR)
- Ask yourself why text is readable when your head is moving, but blurred when the book is moving?
- transduction process is fundamentally similar to that of the cochlea, but it is less well understood, particularly with respect to differences between type I and type II hair cells
- outputs from the vestibular system are integrated with information from other sensory receptors (proprioception=perception of body in space), and are not perceived as separate
- however, when other sensory inputs are in conflict with the vestibular system, the vestibular signal seems to act as the reference postural signal with which other sensory inputs are compared
- unexpected or conflicting inputs from the vestibular system can result in vertigo, nystagmus and/or motion sickness