Vestibular Part 1 Flashcards
List the central vestibular pathway
8VVCROSS
cn 8
Vestibular Nuclei Ipsilateral
Vestibular Nuclei contralateral
cerebellum (to and from)
reticular formation
Occular muscles via CN III, IV, VI
Spinal cord (LVST and MVST)
Superior Sylvian gyrus and SI areas
What 3 systems are involved in balance?
vision
somatosensory
vestibular
all 3 work together for us to keep our balance
what are the two external forces in vestib system
vision and somatosensory
What is the internal reference of vestib system
vestibular
what is the main role of the balance system?
to allow us to interact and maintain contact with our surroundings in a safe and efficient manner
what is ma de debarquement sysndrome (MdDS)
rare vestib disorder that makes you feel like you’re moving even when youre not. most common after travel, usually by boat
what part of the peripheral vestib system happens with acceleration and deceleration
vestibular
what part of the peripheral vestib system happens with standing still
somatosensory
series of interconnected canals and cavities located in the petrous poriton of the temporal bone
labyrinth
located medially and anteriorly in petrous apex
cochlea
located laterally and posteriorly in petrous apex
vestibular
how many sensory organs are there and where are they located
5 in each membranous labyrinth (10 total)
utricle and saccule macula
3 ampullae (cristae ampullaris)
what and where are the vestibular ganglion
scarpa’s ganglion (cell bodies)
located in internal auditory canal
two divisions (superior (LSU) and inferior vestib nerve (PS))
How many and what type of fibers are in vestib?
20,000
primarily bipolar afferent fibers
what is the name of the afferent fiber that branches off of the inferior vestib nerve of CN VIII and attaches to the cochlea
vestibulocochlear ramus
what is the accessory structure in the vestibular?
cupulla
The vestibular system is ________ (more / less) effective when the head or body is still and ________ (more / less) active when the body is in motion.
less (use vision more here)
more (vestib main function here)
Balance is dependent upon sensory information gathered from what three systems?
somatosensory/proprioception
vestibular
visual
What are the two types of sensory structures in the vestibular system and what stimuli do they respond to?
crista ampullaris in SCC - angular acceleration - pitch, roll, yaw?
maculae in utricle and saccule (otolithic membrane)- linear acceleration and gravitational forces
does kinocilium disappear after embryonic development in the vestibular system?
no, just in the cochlea
why may we be able to regenerate hair cells and where?
in the vestibular system because the kinocilia is still present
what are the type of hair cells in the vestib system?
Type 1 and type II
which vestibular hair cell is flask shaped with a large nerve innervating directly by afferent fibers?
type I
which vestibular hair cell is cylindrical and innervated directly by efferent fibers
type II
what produces endolymph in vestibular system?
dark cells
how are kinocilia oriented in the horizontal canal
toward the utricle
how are the kinocilia oriented in the superior/posterior canals
away from the utricle
What fluid movement causes excitation in horizontal canal?
fluid movement from the semicircular canal side and toward the utricle (hits smaller stereocilia first)
what fluid movement causes inhibition in horizontal canal?
fluid movement from the utricle toward the canal (hits kinocilia first)
what fluid movement causes excitation in ant/post canals?
fluid movement from the utricle toward the canal
what fluid movement causes inhibition in ant/post canals?
fluid movement from the semicircular canals toward the utricle
what are the otolithic structures
utricle and saccule
what plays a large role in postural control and senses change in orientation in respect to gravity (moving forward in a car)
utricle
what is in the otolithic membrane to give it density
otoconia
what are embedded in the otolithic membrane
stereocilia and kinocilia
what detects linear acceleration and gravitational forces
maculae (utricle - horizontal saccule - verticle)
calcium carbonate crystals mixed with a protein matrix
otoconia
small grain- or rice-shaped particles with a density that allows the utricle to respond transiently to linear acceleration and in a more practical fashion to head tilt
otoconia
tilt head left =
inhibitory
tilt head right =
excitatory
imaginary line through axis of each maculae which hair cells are organized
striola
axis for polarization allowing for complex stimulation patterns
striola
this allows for a complex multidirectional pattern of responses
the alignment of hair cells around the striola
kinocilia are ____ striola in utricle
toward
kinocilia are ____ striola in saccule
away
primarily registers vertical movement, like going up in an elevator
saccule
how is the saccule connected to the utricle and semicircular canals?
vestibular aqueduct
