Neuro - Vestibular System Flashcards
What are the 3 main inputs of the vestibular system?
1) Visual input
2) Proprioceptive input
3) Vestibular information
What part of the inner ear is used in balance?
The labyrinth
What bone is the labyrinth in?
The temporal bone
How many semicircular canals are there?
3
Where are the utricle and saccule located?
In the vestibule and are joined by a conduit
What structure do the semicircular canals attach to the utricle with?
An ampulla
Why are the semicircular canals on different planes?
So that head movements in all directions can be detected
What hair cells do vestibular hair cells have on them?
1 kinocilium and stereocilia
How do the vestibular hair cells detect movement?
They are surrounded by endolymph and when a person moves the endolymph moves and causes the stereocilia to move which allows the, to become depolarised and send a neuronal impulse.
What are the otolith organs?
The utricle and saccule
What are otoliths?
Crystals that lay above the hair cells in the otolith organs and move with head movement, which allow them to apply weight to the hair deflect the hair cells
Should there be otoliths in the semicircular canals?
No - only present due to a disorder
How does hair deflection occur in the ampulla?
The hair cells are surrounded by cupula and when endolymph moves it causes the cupula to move to one side which helps with hair deflection
Where are the vestibular nuclei located?
In the brainstem
What reflexes can occur as a result of vestibular information?
Vestibulospinal reflexes
Vestibulo-ocular reflexes
Vestibulocerebellar reflexes
What is considered ‘otolith movement’?
Linear acceleration and tilt
What type of movement does the utricle detect?
Horizontal movement
What type of movement does the saccule detect?
Vertical movement
What movement do the semicircular canals detect?
Angular acceleration
What occurs in vestibulo-ocular reflexes?
Eye movement in the opposite direction to the head movement at the same velocity and amplitude
What is the main symptom of a vestibular disorder?
Vertigo
What components can be involved in a peripheral vestibular disorder?
The labyrinth or VIII nerve
What can cause central vestibular disorders?
Conditions such as stroke, MS and tumours
