11 Auditory System Flashcards
Hearing involves the (3)
external ear
middle ear
inner ear
What is the nerve that innervates the organ of corti in the inner ear and relays auditory impulses to the cochlear nuclei in the medulla oblongata
cochlear nerve
external ear consists of
Pinna (outer visible part)
External acoustic meatus (ear canal/auditory canal)
-Sound waves induce vibration in this part
-separates the external ear from the middle ear
tympanic membrane
The middle ear is an air-filled ____ cavity
tympanic
The middle ear communicates with the ____ via the auditory tube, which functions to equalize the pressure in the tympanic cavity with the pressure in the external auditory canal.
nasopharynx
What are the auditory ossicles in the middle ear
malleus
incus
stapes
ossicle that is attached to the tympanic membrane
malleus
the footplate of the stapes fits into the ____ in the bony wall between the middle and inner ear.
vestibular window
What provide a mechanical linkage between the tympanic membrane and the vestibular window.
The ossicles
Where is the sensory receptor for hearing located
inner ear
The bones that form a bent lever
malleus and incus
Importance of the bent lever design in the middle ear
-magnifies the vibratory pressure of the tympanic membrane transmitted to the stapes essential as the sound waves are transferred from air to fluid medium in the inner ear.
-it decreases the amplitude of sound waves at the vestibular window which protects the sensitive sensory cells of the organ of Corti.
The inner ear contains the sensory organs for (what systems)
auditory system
vestibular systems
The cochlea is composed of three tubular chambers?
vestibular duct (scala vestibuli)
cochlear duct (scala media)
tympanic duct (scala tympani).
Parts of the cochlea that are connected by helicotrema and are filled with fluid called perilymph, which has a high concentration of Na+ ions.
Scala vestibuli
Scala tympani
The scala vestibuli at the basal end faces the ____ window, whereas the scala tympani faces the ____ window.
vestibular window
cochlear window
What lies between the scala vestibuli and scala tympani and is filled with endolymph (K+)
cochlear duct (scala media)
-What is the sensory organ for the auditory system
-It lies within the cochlea, separating the scala vestibuli and the scala tympani
Organ of the Corti
The cochlear duct (scala media) is separated from the scala vestibuli by the
vestibular membrane
The cochlear duct (scala media) is separated from the scala tympani by the
basilar membrane
-are referred to as sensory hair cells because of their stereocilia at the apical surface
-have 50–100 stereocilia on their apical surface.
Sensory cells
-they are connected at the tips of the stereocilia
-is composed of filamentous material, where one end is attached to the side of the stereocilium and the other end to the distal end of the adjacent shorter stereocilium.
-It is speculated that it is attached to a K+ channel that enables K+ channels to open when bending of the stereocilia pulls it apart.
tip links
-a gelatinous structure composed primarily of glycoproteins, overlies the sensory cells, embedding the tips of the longest stereocilia of sensory hair cells.
-Because of this structural arrangement, vibratory movement of the basilar membrane causes stereocilia of the sensory hair cells to bend. The hair cells translate this mechanical bending of stereocilia into voltage changes in the cell membrane.
tectorial membrane
