Auditory and vestibular systems Flashcards
what functional fiber type is found in CN VIII? Is it the same for both auditory and vestibular systems?
The fiber type is SSA pseudounipolar neuron, which is used for both divisions of CN VIII
What are the parts of the external ear canal?
pinna / auricle, and the tympanic membrane
what is the function of the external ear canal?
to funnel sound waves into the inner ear
what are the structures of the middle ear?
the tympanic membrane, the auditory ossicles (malleus, stapes, incus), the middle ear muscles, the cochlear window and vestibular window, and the eustachian/auditory tube
what does the tympanic membrane do?
sound waves will cause a reverberation on the tympanic membrane to the auditory ossicles
what do the auditory ossicles do?
they transfer the sound waves to the cochlea
what do the middle ear muscles do?
they help regulate sensitivity to sounds
what does the eustachian tube do?
it connectrs the middle ear to the nasal part of the pharynx and will equalize pressure between inner andouter ympanic membranes as well as drain fluid from the middle ear
what are the bony labyrinths of the inner ear?
the bony labyrinths are within the semicircular canals (3 of them), the cochlea (coiled shell), and the vestibule (common area between the other two) and they contain perilymph
what are the membranous labyrinths?
they are membranous tubes found within the bony labyrinth filled with endolymph, contain 3 in the semicircular ducts, a coiled shell in the cochlear duct, and a vestibule with the utricle and saccule.
What is the function of the semicircular duct in the membranous labyrinth compared to the cochlear duct in the membranous labyrinth?
the semicircular duct is the vestibular sense, the cochlear duct is the hearing sense
Describe the structure of hair cells
They have a cell body that sits in the perilymph, and is connected to CN VIII, and cilia that are in the endolymph detecting changes.
What is the ion channels for the kinocilium and how are they gated?
The ion channels are cation channels that allow the flow of potassium into the cell, activated voltage gated calcium channels, and triggers a release of a neurotransmitter for AP firing rate to increase in CN VIII neurons.
What happens to the kinocilium with detection of sound?
if the other cilia are deflected towards the kinocilium it will stretch the tiplink, with cation channels opening and calcium channels opening for a neurotransmitter to be released from CN VIII. If deflected away, tiplinks shorten and none of this happens.
What happens
