12.0 Vestibular System Flashcards
What is the origin of the afferent fibers to the vestibular apparatus?
The vestibular ganglion.
Which vestibular nuclei are associated with the lateral vestibulospinal tract?
What about the medial vestibulospinal tract?
Lateral vestibulospinal tract: lateral and inferior vestibular nuclei
Medial vestibulospinal tract: medial, as well as the lateral and inferior vestibular nuclei.
Which portion of the vestibular apparatus detects torsional movements for the vestibuloocular reflex?
Vertical canal and utricle.
What is the function of the insular areas of the lateral sulcus and parietoinsular vestibular cortex (PIVC)?
Responds to body motion, somatosensory, proprioceptive, and visual motion stimuli
Lesions cause vertigo and loss of perception
What is the name of the disease associated with excessive pressure in the membranous labyrinth?
What are the symptoms?
Meniere’s Disease
This causes several symptoms:
Fluctuating hearing loss
Tinnitus
Vomiting
Nystagmus
Other vestibular sx.
Which portion of the vestibular apparatus accounts for horizontal movements for the vestibulocular reflex?
The horizontal semicircular canals and utricle.
What is the function of the medial vestibulospinal tract?
Vestibular stimulation of the neck muscles.
Which portion of the vestibular apparatus detects vertical movements for the vestibulocular reflex?
Vertical semicircular canal and saccule
How do hair cells detect motion?
The vestibular sensory receptors are hair cells with stereocilia that project from the apical surface. They all contain stereocilia and one long kinocilium. That kinocilium causes an activating signal when the stereocilia bend towards it, and an inhibitory signal when they bend away.
Which portions of the vestibular apparatus is involved in the detection of translational movement?
The utricle and saccule.
What two arteries supply the blood supply to the vestibular system?
The labyrinthine artery and the stylomastoid artery.
How does the vestibular system coordinate movements between the right and left?
Vestibulovestibular fibers, which are collateral fibers between the right and left vestibular nuclei (left superior vestibular nucleus to right, and so on).
What are the two different parts of the lateral vestibulospinal tract?
What are their functions?
Anterorostral areas: vestibular stimulation of the cervical spinal cord fibers.
Posterocaudal regions: vestibular stimulation of the lumbosacral cord.
What are the vestibular functions of the prefrontal cortex and superior frontal gyrus?
Receive vestibular signals and are related to the frontal eye field.
Controls “saccades” and smoothes out eye movements.
If the medial longitudinal fasciculus was cut, what muscle would not turn during the vestibulocular reflex?
The ipsilateral (to the turn) medial rectus.
If your head was turning left, your medial rectus would not pull your left eye to the right, because the fibers from the contralateral abducens to the ipsilateral oculomotor nucleus would be severed.
