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Hearing
Morrow 6/24/11 lecture 2 hrs (really 1)
134
Histology
Undergraduate 4
06/06/2011

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Cards

Term
hearing and equilibrium
Definition
what are the 2 functions of the ear?
Term
1) external ear
2) middle ear
3) inner ear
Definition
name the 3 gross divisions/parts of the ear
Term
middle and external ear
Definition
what part of the ear is used for perception, transmission, and amplification of sound waves(hearing)
Term
inner ear
Definition
In what part of the ear are the sensory receptors for hearing & the organs of equilibrium?
Term
elastic cartilage + skin, aka the external ear, or auricle
Definition
what is the pinna?
Term
elastic
Definition
what kind of cartilage is the ear made of?
Term
the external auditory meatus (ear canal) then to the ear drum
Definition
where does the pinna funnel sound into(what is its purpose)?
Term
tympanic membrane
Definition
fancy schmancy name for the ear drum
Term
1) external CUTICULAR epithelial layer
2) middle FIBROUS layer of collagen
3) inner MUCOUS layer
Definition
list the 3 layers of the tympanic membrane from external to internal
Term
the inner mucus layer of the tympanic membrane
Definition
what ear part is continuous with respiratory epithelium, but without cilia or goblet cells?
Term
cerumen
Definition
name for ear wax
Term
apocrine sweat glands
Definition
what kind of glands are ceruminous glands modified versions of?
Term
external ear canal
Definition
where are ceruminous glands located?
Term
petrous temporal bone
Definition
what bone is the middle ear in?
Term
the tympanic membrane
Definition
where is the boder between the external and middle ear?
Term
simple squamous to cuboidal epithelium
Definition
what lines the middle ear cavity?
Term
amplify and convert sound waves to mechanical signals transmitted to a liquid medium
Definition
what is the job of the middle ear?
Term
sound waves strike the ear drum, and the ossicles amplify them and convert them to mechanical signals
Definition
how does the middle ear function?
Term
the oval window of the fluid-filled inner ear
Definition
where does sound immediately go as it leaves the middle ear?
Term
1) malleus
2) incus
3) stapes
Definition
name the ossicles
Term
malleus
Definition
which ossicle is in contact with the tympanic membrane?
Term
stapes
Definition
which ossicle is in contact with the oval window?
Term
middle ear
Definition
where are the ossicles found?
Term
Incus (anvil)
Definition
what does Wile E Coyote drop on Road runner?
Term
bones in the jaws (of reptiles) (which come from gill arches of fish)
Definition
where do the ossicles come from evolutionarily?
Term
the SINGLE ear ossicle of birds, reptiles, and amphibians
forms from the hyomandibular gill arch
Definition
what is a columella? what does it form from?
Term
the stapes
Definition
what is the columella in mammals?
Term
the quadrate:articular jaw joint of reptiles becomes modified to become the dentary squamosal jaw joint in mammals

quadrate -> incus
articular -> malleus
Definition
where do the incus and malleus bones come from?
Term
pelycosaur (has the full jaw joint intact)
Definition
sail/fin back reptile from the early paleozoic era
Term
Therapsid (their jaw is in the middle of an early mammal's and a pelycosaur)
Definition
early mammal-like reptiles
Term
the melon organ
Definition
name the part in the dolphin that is a modified fat pad that helps them make sounds with their jaw bone
Term
synovial joint
Definition
what kind of joints are the joints between the ossicles?
Term
tensor tympani
Definition
muscle that attaches to the handle of the malleus and keeps the eardrum taut
Term
stapedius
Definition
muscle that attaches to the stapes and oval window
Term
they contract to dampen loud noises
Definition
what is the job of both stapedius and tensor tympani?
Term
when you hear a loud sound, the tensor tympani and stapedius contract to dampen the noise(by allowing the ossicles to move less) and prevent damage to the sterocilia of the inner ear
Definition
what is the attenuation reflex?
Term
the eustacian/auditory tube
Definition
how does the middle ear communicate with the nasopharynx?
Term
eustachian tubes
Definition
allows equilibration of air pressure in the middle ear with the external environment
Term
pseudostratified, ciliated, columnar (respiratory) epithelium
Definition
what lines Eustachian tubes?
Term
swallowing will help open your Eustachian tube, so does yawning
Definition
why should you chew gum on an airplane?
Term
temporal
Definition
what bone is the osseus(bony) labyrinth in?
Term
the fluid-filled sacs of the membranous labyrinth
Definition
what is found in the bony labyrinth?
Term
simple squamous to columnar epithelium
Definition
what kind of epithelium lines the sacs of the membranous labyrinth?
Term
endolymph
Definition
what kind of fluid is in the membranous labyrinth?
Term
perilymph, in the vestibule
Definition
what kind of fluid surrounds the sacs of the membranous labyrinth? what is this space known as?
Term
the oval window
Definition
what separates the middle ear(vestibule) from the inner ear?
Term
1)cochlea
2)vestibular aparatus
3)the vestibule
Definition
what are the 3 areas of the osseous labyrinth?
Term
cochlea
Definition
part of the osseous labyrinth used for hearing
Term
vestibular apparatus
Definition
part of the osseous labyrinth used for motion detection and maintaining orientation
Term
1) semicircular ducts/canals
2) sacculus
3) utriculus
Definition
name the regions of the vestibular apparatus
Term
the saccule and utricle (in the membranous labyinth)
Definition
what is located between the semi-circular canals and the cochlea?
Term
they are part of the membranous labyrinth, so they are filled with endolymph
Definition
what kind of fluid is found in the saccule and utricle?
Term
vestibule
Definition
name the central space that give rise to the semi-circular canals and cochlea
Term
oval window
Definition
what separates the vestible from the middle ear?
Term
used for sound wave dissipation
Definition
what does the round window do?
Term
both the saccule and utricle, and in the semicircular canals
Definition
where are the special sensory Type I and Type II cells found?
Term
Type II cells
Definition
aka hair cells, or columnar cells that have stereocilia and a kinocilium
Term
1 large kinocilium, but a cluster of sterocilia
Definition
how many sterocilia do type 2 cells have? how many kinocilium?
Term
Type I
Definition
which special sensory cells are goblet cells?
Term
macula
Definition
one side of the sacculus and utriculus that has the cluster of stereocilia and 1 associated kinocilia
Term
glycoprotein layer (hair cells are embedded in it)
Definition
layer of goo overlying hair cells in the macula
Term
the glycoprotein layer around hari cells
Definition
what supports otoliths/otoconia?
Term
little rocks that float on top of the glycoprotein coat of hair cells
Definition
what are otoliths?
Term
calcium carbonate crystals
Definition
what are otoconia/otoliths made of?
Term
the otoliths shift in the goo layer and bend the cilia, which signals a nerve
Definition
how do you detect motion?
Term
they send a signal down the afferent axons which go to the vestibular nerve
Definition
what happens when hair cells bend?
Term
LINEAR acceleration, and gravity
Definition
what motions do the hair cells of the saccule and utricle detect?
Term
take a crayfish and relace its otoliths with iron filings, then take a magnet and pass it by the ear, they will think that down is whatever direction the magnet is
Definition
how do you trick the otolith system?
Term
semi-circular canals
Definition
3 horse-shoe shaped canals oriented at right angles to one another in coronal, horizontal, and sagittal planes
Term
endolymph (they are part of the membranous labyrinth)
Definition
what fills the semicircular canals?
Term
ampulla
Definition
name the dilated area at the base of the semicircular canal
Term
crista ampullaris
Definition
name the ridge inside the ampulla of semicircular canals
Term
type 1 and 2 hair cells with stereocilia (embedded in a glycoprotein layer)
Definition
what cells are found in the semi-circular canals?
Term
cupula
Definition
name the glycoprotein layer that surrounds cells in the semicircular canal
Term
ANGULAR acceleration, and decelleration
Definition
what motions do the semicircular canals respond to?
Term
NO OTOLITHS in the semicircular canals
Definition
what is the difference between the semicircular canals and the saccule/utricle?
Term
movement of the head moves the endolymph(bending cilia), which stimulates the receptors cells and signals the brain via the vestibular nerve
Definition
how are receptor cells stimulated in the semicircular canals?
Term
vestibular N.
Definition
what nerve do the afferent fibers go to that function in balance and equilibrium?
Term
2
Definition
how many semicircular canals can be stimulated simultaneously?
Term
pitch: up and down, front to back (rotate around a transverse axis like fusball guys
yaw: vertical axis of rotation (left and right) = horizonally positioned semicircular canal
roll: longitudinal axis of rotation (told from side to side)
Definition
relate the motions of the semicircular canals to movements of a boat
Term
1) sagittal
2) coronal
3) horizontal
Definition
what are the 3 planes the semicircular canals are in?
Term
semicircular canals
Definition
works with crista ampullaris to determine different body movements
Term
modiolus
Definition
the cochlea is a spiral/conical organ surrounding a bony core, name the bony core
Term
anterior portion of the vestibule
Definition
what does the modiolus attach to?
Term
endolymph in some parts
perilymph in other parts
Definition
the cochlea continuous with the sacculus, utricles, and semi circular canals, so what kind of fluid does it contain?
Term
sacculus
1) (upper) scala vestibuli
2) scala media/cochlear duct (middle)
3) (lower) scala tympani
Definition
what does the membranous portion of the cochlea attach to? what are the 3 compartments contained in it?
Term
endolymph
Definition
what type of fluid is contained in the scala media/cochlear duct?
Term
perilymph
Definition
what type of fluid is contained within the upper scala vestibuli and lower scala tympani?
Term
vestibular membrane aka Reissner's membrane
Definition
membrane between scala vestibuli & scala media
Term
basilar membrane
Definition
membrane between scala media and scala tympani
Term
stria vascularis
Definition
what is found in the lateral wall of the scala media that secretes endolymph?
Term
helicotrema
Definition
opening connecting the scala vestibuli and scala tympani
Term
on the basilar membrane
Definition
where are the special sensory cells for hearing located?
Term
inner and outer hair cells
Definition
name the special sensory cells that line the scala media
Term
inner and outer hair cells, surrounded by support cells
Definition
what makes up the organ of corti?
Term
inner and outer pillar cells
inner and outer phalangeal cells
Definition
name the support cells for the hair cells of the Organ of Corti
Term
tunnel of Corti
Definition
a tiny space in the organ of Corti surrounded by the hair cells, the pillar cells and the phalangeal cells
Term
a gelatinous layer: the tectorial membrane
Definition
just like the sacculus and utriculus and crista ampularis something rests on top of the hair cells of the scala media, name it
Term
cochlear nerve
Definition
what nerve do the hair cells synapse with?
Term
1 single row (so ~3,500)
Definition
how many rows of inner/internal hair cells are there?
Term
inner hair cells
Definition
90-95% of the cochlear nerve fiber terminate on this type of hair cell
Term
inner hair cells
Definition
which hair cells are responsible for sound transduction(hearing)
Term
in a straight line
Definition
how are stereocilia arranged on inner hair cells?
Term
v shape
Definition
how are stereocilia arranged on external hair cells?
Term
3-4 rows (~12,000 cells)
Definition
how many rows of external hair cells are there?
Term
outer hair cells
Definition
what cells are responsible for modifying the sensitivity of inner hair cells (frequency descrimination)?
Term
tip links
Definition
name the filaments that connect the tips of stereocilia on outer hair cells
Term
reticular lamina
Definition
name the rigid plate that holds the stereocilia in place like a sieve
Term
1) reticular lamina
2) tectorial membrane
Definition
name the layers that the hair cells project into, in order
Term
a long cilium off to the side of the cluster of stereocilium on hair cells
Definition
what is a kinocilium?
Term
potassium channels open, causing depolarization

bending in the opposite direction would cause hyperpolarization
Definition
what happens as a result of stereocilia bending?
Term
so that you don't hear a second sound when your hair cells straighten back up
Definition
why do stereocilia only cause depolarization in one direction?
Term
cochlea
Definition
functions as a transducer by converting mechanical energy(vibration) into electrical signals that are percieved as sound
Term
high frequency (pitch) sounds
Definition
what type of sound is detected by the BASE of the cochlea?
Term
low frequency
Definition
what type of sounds are detected at the apex of the cochlea?
Term
high frequency sound
Definition
what type of hearing is first to be lost with age?
Term
its more narrow at the base than the apex
Definition
where is the basilar membrane most narrow in the cochlea?
Term
different parts of the cochlea are specialized for different pitches/frequencies of sound, and this corresponds to different areas of the brain
Definition
what is a tonotopic map?
Term
11 octaves
Definition
how many octaves of sound can your brain detect?
Term
1) nerve deafness (cochlea and cochlear nerve impairment)
2) conduction deafness (impairment of the mechanism of conducting sound into the cochlea)
Definition
name the two types of deafness
Term
nerve deafness
Definition
what type of deafness is considered permanent deafness?
Term
endocochlear implant that stimulates the nerve directly

younger the child is when implanted, the better chance of hearing recovery
Definition
how do you treat nerve deafness?
Term
you will be blind -> there is a learning curve for the neurons
Definition
if you are not exposed to light a certain amount of time after you are born, what happens?
Term
decreases ability to hear high frequencies
Definition
what does prolonged exposure to loud sounds do?
Term
presbycusis
Definition
age-related loss of high frequency hearing
Term
ototoxic: damage hair cells in organ of Corti

-> antibiotics in too high doses such as streptomyosin, kanamycin, chloramphenacol
Definition
name some ototoxic drugs
Term
ankylosis, fibrosis of ear ossicles(otosclerosis)
Definition
what are the other names for conductive hearing loss
Term
otitis media
Definition
due to bacterial seeding of the middle ear from the nasopharynx via the Eustachian tubes
Term
otitis media
Definition
this is frequently associated with swimming due to retrograde displacement of water into the middle ear
Term
otitis media
Definition
this is frequently associated with swimming due to retrograde displacement of water into the middle ear
Term
conduction deafness
Definition
what can result from a middle ear infection/inflammation (otitis media)
Term
your middle ear (it's like a petri dish when you swim)
Definition
its dark, its moist, its warm, what more could you ask for as a bacteria?
Term
lance the ear drum (poke a hole in and drain the pus so the ear drum doesn't pop
Definition
what is an initial treatment for otitis media?
Term
a tiny prostethic ceramic implant (prosthesis) can be used to replace the stapes
Definition
how do you correct otosclerosis later in life?
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