Exam2Lec5Ear Flashcards
What is the fxn of the outer ear?
receives incoming sound waves
hearing + equilibrium
hearing involves gathering sound by the ____ ear, amplification by the ____ ear, and transmitting vibrations from air to fluid in the ____ ear, converting vibrations to nerve impulses
outer, middle, inner
Equilibrium involves structures of the ____ ear for angular position sense and linear accelearation.
inner
How does sound travel within the outer ear?
auricle (pinna), external auditory meatus, tympanic mem (eardrum)
What is outer ear lined with?
keratinized Strat sq epti + elastic cart
auricle specificcally is covered by this
What lines the external auditory meatus and what does it contain ?
Lined by skin and contains ceruminous glands
What covers the outer surface of tympanic membrane?
covered by skin
What produces ear wax?
ceruminous glands
What is the fxn of the middle ear?
transmits sounds from outer to inner ear
more specifically from tympanic membrane to inner ear
Structures of the middle ear
- tympanic cavity
- auditory or eustachian tube
- auditory ossicles
- oval and round window
Where is the middle ear housed in and what is this structure lined with?
housed in: tympanic cavity
lined w/ simple sq epith (from ectoderm)
What structure is important for rebounding sound?
round window
releaves pressure by dampeneing reflection bacl
The auditory (eustachian) tube is located in what part of the ear and what type of epithelium is it lined with?
within middle ear
ciliated pseudo colum epith
What is the fxn of auditory (eustachian) tube?
connects middle ear to nasopharynx
helps to change prressure in order to maintain equilibrium
Middle and inner ear is sep by two small thin membranes, what are they?
oval and round window
What are the osscile of the middle ear?
malleus, incus, stapes, oval window
stapes pushes on oval window, malleus pushed by tympanic membrane
The middle ear has 2 small muscles, what are they and what do they help with?
Stapedius and tensor, helps regulated vibration to dampen loud sound
What is the fxn of the inner ear?
hearing and balance (equilibrium)
contains sensorineural organs
Structures of the inner ear
- bony labyrinth and vesitibule, semicirc canals, and cochlea
- Membranous labyrinth and its utricle, sacule, semirc ducts, cochlear duct, maculae, crista ampullaris, organ of corti
What is the bony labyrinth filled with? What does it contain?
Filled with perilymph
contains: vestibule + semicircular canals + cochlea
carved out of (space within) temporal bone
What is the membranous labyrinth filled with? What does it contain?
filled with endolymph
contains: saccule + utricle + semicirc ducts + cochlear duct
Explain how sound goes through the cochlea
- Scala media=cochlear duct contains the cochlea which converts vibrations in the perilymoh in the scala vestibuli and endolymph in the cochlear duct
- intenal ear fluid movemnt from vibration of oval window sets a vibration in the basilar membrane and results in movement in the hair cells and then nerve impulses
What structure is responsible for hearing?
cochlea
What is the cochlea covered by and what does it contain?
Covered by bony labryinth and contains the cochlear duct covered by membranous labyrinth
What are the 3 chambers of the cochlea?
scala vestibuli, media, and tympani
Cochelar duct=
scala media (w/endolymph)
What 4 struc does the cochlea contain?
- Organ of corti
- Hair cells w/ stereocilia
- Tectorial memb rane
- Basilar membrane
Fxn of organ of corti
receptor for hearing
Fxn of hair cells w/ stereocilia?
Convert sound to neural impulse
What is the fxn of the tectorial membrane?
attached to hair cells
Fxn of the basilar membrane
supports organ of cort
generates diff sound frequences
The base (narrow portion) of basilar membrane generation what pitch of sound?
high pitch
The apex (wide portion) of basilar membrane generation what pitch of sound?
low
Displacement of stereoclilia in hair cells of tectorial membrane results in generation of what?
Action potential
What are the steps of sound transmission?
- Sound travels up scala vestibuli –>makes waves in perilymph–> transferred to scala media (endolymph)
- Waves in endolymph move basilar membrane –> stimulates hair cells –>stereocilia move against tectorial membrane
- Sound is turned into action potential –> neural impulses
Excess vibration travel down ____ and is absorbed by ____.
scala tympani, round window
The crista ampullaris is located where?
In the semicircular duct (membranous labyrinth) in the inner ear
What is the fxn of the crista ampullaris?
sensor of angular motion (acceleration)
What is the crista ampullaris covered by?
Cupula=gelatinous membrane
movement of endolymph in the duct displaces the cupula, this stimulates hair cells
Where is the maculae located?
In the saccule + utricle of the vesitble
can word it as “ the saccule of the vestibule”
What is the fxn of the maculae?
gravity + linear acceleration
What is the maculae covered by?
Otoconia=little crysrals that push down on stereocillia of hair cells
the otolithihc membrane underlies the otoconia and is displace during acceleration
What is the kinocilium?
Microtubules that interact w/ sterocilia displacd by otoconia
movements towards kinocilium opens channels, movemnt away closes channels
What innervates the ear?
Vestibular (come of semi circ canals) and cochlear (come off spiral ganglion) nerves
