Lectrue 32 - Vestibular Physiology Flashcards
Balance definition?
the integration of visual, vestibular, proprioception and superficial sensor information
Acute and chronic deterioration?
minor acute derangement leads to catastrophic result (vertigo); chronic loss could have limited consequences due to compensation at central nuclei
Vertigo definition?
perception of motion or environment when there is none
Motion sickness definition?
conflict between vestibular nuclei & proprioception inputs compound with expected internal model; mismatch promotes symptoms (nausea)
Vestibules and cognition?
self-motion perception, bodily self-consciousness, spatial navigation, memory and object recognition memory
Vestibular system compositions?
peripheral system (semicircular canals and otolith organs), vestibular nuclei in brainstem, vestibular portion of CN VIII
Semicircular canals?
anterior, posterior, lateral
Otolith organs and function?
Succule (static head position), utricle (linear acceleration)
Semicircular canal pairs?
anterior pairs with posterior of opposite cells, lateral canals pair with each other
Vestibular nerve innervation - superior division?
utricle, anterior saccule, lateral and anterior semicircular canals
Vestibular nerve innervation - inferior division?
post. saccule, posterior semicircular canal
Hair cell alignment?
polarised and arranged so that they are aligned in same direction
Pair hair orientation?
pairs are oriented in opposite directions, therefore one side is inhibited as the other is excited - brain relies on comparison of discharge patterns from both sides to determine direction of movement
Projections from vestibular nuclei?
VOR (maintain gaze while moving), vestibulo-spinal pathways (posture), hippocampus
VoR is vestible -> vestibular nuclei and then?
III -> medial rectus of ipsilateral eye OR VI -> lateral rectus of contralateral eye
