(Comprehensive Test from StudyBlue) Flashcards
from StudyBlue
Auditory deprivation
The brain gradually loses some of its information processing ability.
neuroplasticity
brain’s ability to change and adapt
at some point the brain will stop changing
cross modal plasticity
adaptive reorganization of neurons to integrate the function of two or more sensory systems
type of neuroplasticity that often occurs after sensory deprivation due to disease or brain damage.
critical window for hearing
6 months
language development for children
birth to 2 years
auditory skill development for children
birth to 3.5 years
intervention before ____ months results in normal cognitive and linguistic development
6
average number of words heard by a child in the first 4 years of life
1 Million words
outer portion passes through cartilage, has sebaceous glands (forms cerumen), inner portion passes through tympanic portion of temporal bone, inner and outer portion meet at osseocartilaginous junction
External auditory canal
Father of audiology
1945 Raymond Carhart
what percentage of babies are born to normal hearing parents?
90-95%
evolution of audiology
- prior to WWII there were hearing aid dealers 2. military had hearing loss 3. needed rehabilitation centers 4. Latin root-audire (to hear) greek suffix-logos (to study)
External Auditory Canal Angle in children
angles downward more acute angle, children’s pinna pulled down and back when looking into ear
before age ___, ____% of children in U.S. will have at least one ear infection
6, 90%
Effects of HL on adults
- overall poor health 2. decreased physical activity 3. depression 4. progressive physical and psychosocial dysfunction
only ___% of individuals seek treatment for hearing loss
25%
why don’t people seek treatment?
Embarrassed, financial reasons
Degrees of HL
normal: 0-25 dB
mild: 26-40,
moderate: 41-55,
moderately severe: 56-70,
severe: 71-90
profound: 91+
what can audiologists do in their scope of practice
- evaluate and diagnose hearing loss and vestibular disorders 2. perscibe, fit, and dispense hearing aids and other amplification and hearing assistance technologies 3. members of cochlear implant teams/cleft palate, and others. 4. perform ear or hearing related surgical monitoring 5. designed and implement hearing conservation programs. 6. implement newborn hearing screening programs 7. provide hearing rehabilitation training 8. treat individuals with central auditory processing disorders 9. assess and treat tinnitus
Father of otology
1835 Adam Politzer
Academic Preparation for audiologist
4 year long program with “capstone”. Foundation of Audiological sciences are the 1st year; diagnostics and treatment after that, then externship
External Auditory Canal Function
- allows for protection of tympanic membrane 2. filter to reduce low frequency and as a tube resonator between 2000-7000 Hz.
Tympanic Membrane
- concave 2. marks border between outer and middle ear 3. area: 90mm 4. Has three layers 5. extremely thing 6. efficient vibrating surface 7. very rich in blood supply 8. malleus is embedded in fibrous portion of TM
Three layers of the tympanic membrane
- Cutaneous: Outer layer (skin), continuous with external canal.
- Fibrous: Provides most of the structure and compliance (density is greatest at center); has radial fibers and spiral (circular) fibers (looks like a web).
- Internal: Mucous membrane, continuous with middle ear cavity.
4 quadrants of tympanic membrane
1.anterior superior (front, back) 2.anterior inferior (front, below) 3.posterior inferior (back, below) 4.posterior superior (back, above)
what does the malleus do
contracts and pulls tympanic membrane inward to help sound travel
development of the outer ear 28 days after conception
- bulges appear on either sir of the tissue 2. develops pharyngeal arches 3. pinna develops from pharyngeal arches 4. pinna develops before the 2nd fetal month
what forms in the third fetal month
tympanic membrane
what forms in the 4th gestational week
external auditory canal
what is done developing after 20 weeks of gestation
full ear
what is the “bowl” part of the outer ear called?
concha
is the middle ear air-filled or fluid-filled
air-filled
how large is the middle ear
1/2 inch high 1/4 inch deep
what is the roof of the middle ear like?
thin layer of bone separating middle ear cavity from the brain
what is the space in the middle ear above the tympanic membrane
epitympanic recess
what is the middle ear lined with?
mucous membrane
what does the middle ear connect to?
nasopharynx
the middle ear and _____form the ________
the middle ear and EUSTACHIAN TUBE form the MIDDLE EAR CLEFT
topmost cells of the middle ear are called…
cilia
what is the eustachian tube lined with
ciliated epithelium
are eustachian tubes in adults open or close?
closed
the eustachian tube enters the middle ear at ___ degree angle
30
while we are awake the eustachian tube opens…
once per minute
while we are asleep the eustachian tube opens every….
5x per minute
the eustachian tube in infants are…
shorter wider more horizontal than adults
the eustachian tube in infants remain open until about…
6 months
Eustachian tube
- courses from the floor of the middle ear to the back of the throat (nasopharynx), 2. maintains a pressure equilibrium with the ambient outside pressure. 3. Allows fluid trapped in the middle ear to be drained. 4. Muscles: tensor veli palatini (TVP) and Levator veli palatini (LVP)
mastoid
-not solid -honey combed -mucous membran lining -aditus and antrum - communication with middle ear cleft
2 windows of middle ear
Oval - entrance to inner ear (stapes) Round- exit of inner ear (thin membrane)
Malleus
Comes in contact with TM. Point of attachment is the Umbo
incus
transmits vibrations to stapes
stapes
sends vibration to oval window –> inner ear (fluid filled) displaced fluid will displace hair cell movement and send action potentials action potentials travel down cochlear branch
effective vibrating area of tympanic membrane is ____
55mm
tympanic membrane is ___times the oval window
17
the ossicular chain is designed to take advantage of the ___
physical law of leverage
the ossicular chain rock back and forth on an axis like a ___
pivot
the combined effects of increase pressure and the lever action of malleus is…
increase pressure at oval window at 23 times.
value is equivalent to 30 dB.
What are the muscles of the Middle ear?
*Tensor Tympani:pull malleus anteromedially, stiffen ossicular chain *Stapedius: : rotate stapes posteriorly, stiffen ossicular chain
inner ear is made up of two parts
- Hearing (cochlea) 2. Balance (vestibular system, semicircular canals
vestibule
entryway into inner ear beyond the oval window
vestibule is filled with what kind of fluid
perilymph
2 fluids in the inner ear?
perilymph - fluid outside the ducts, high [Na+], in the scala vestibuli and scala tympani
endolymph - fluid inside the ducts, high [K+], in the scala media
scala vestibuli upper chamber contains
perilymph
scala media is filled with
endolymph
reissner’s membrane
separates the scala media and scala vestibule
basilar membrane separates the…
scala media and scala tympani
scala tympani is filled with
perilymph
how many times does the cochlea turn
2.5
organ of corti (organ of hearing)
-lies on the scala media side of the basilar membrane -divided into inner and outer portions by rods of corti -contains hair cells -the inner tunnel of corti contains cortilymph
function of the cochlea
- traveling wave in cochlear duct. 2. basilar membrane moves 3. hair cells shear 4. cilia of hair cells bend 5. chemical release, mechanical release, cochlear microphonic 6. action potential and then to auditory nerve.
where does the organ or corti sit?
the basilar membrane
physiology of cochlea
stapes moves, displaces perilymph, basilar membrane moves, hair cells at organ of corti are bent, cilia bend and ionic exchange occurs, release of neurotransmitters, electrical impulses via VIII nerve to brain
how many outer hair cell rows are there?
3
Define the mechanics of the Organ of Corti
Sound waves vibrate the basilar membrane and tectorial membrane which shear the hair cells and polarize the receptors
otoacoustic emmissions
low levels generated in ear in response to sound only in normal ears. Evoked Otoacoustic Emissions Spontaneous Otoacoustic Emissions
OAE
became screening test for newborns
-infants that ears produce evoked emissions have normal peripheral hearing or hearing loss no worse than 30dB
-OAE will refer for even the slightest conductive component or cochlear hearing loss.
EMISSIONS COME FROM OUTER HAIR CELLS
ABR test
measures everything including if sound is going to brainstem
IE- Auditory Neuron - neuron
A specified cell designed as a conductor of nerve impulses
Human cochlea has about 30,000 afferent neurons and about 1, 800 efferent neurons
fluids of cochlea
- endolymph (vestibular and scala media) high in potassium and low in sodium 2. perilymph (scala vestibuli and scala tympani) low in potassium and high in sodium
auditory nerve
the 8th cranial nerve that carries the info from the inner ear to the brain about hearing and balance
1. attaches to brainstem 2. auditory and vestibular portion of VIII nerve separate.
cochlear microphonic
- basically the cochlea does the same thing that a microphone does to different forms of energy
- stereocilia stretch causing release of K+ ions into hair cells causing change in the resting potential and release of transmitter substance (glutamate)-compare to changes in form of energy in a microphone
- acoustic energy–> mechanical–>electrical (after strikes hairs and goes to cochlea nerve–>through 5 nuclei–> on the way up to temporal lobe
action potential
- auditory neurons stimulated by hair cells 2. change in electrical potential occurs on the site of the neuron. 3. increases in intensity of the auditory input signal to the cochlea, increase electrical output from hair cells.
ascending auditory pathway
- ACSLIMA (from bottom to top) 1. auditory nerve (VIIIth nerve) 2. cochlear nucleus 3. superior olivary complex 4. lateral lemniscus 5. inferior coliculus 6. medial geniculate body 7. primary auditory cortex
superior olivary complex (SOC)
receive input from both ipsilateral and contralateral cochlear nuclei
where sound crosses over to the other side.
cochlear nucleus (CN)
cluster of cell bodies in the brain stem where the nerve fibers leading from the cochlea enter and synapse
lateral lemniscus
carries sound info from cochlear nucleus to various brainstem nuclei and ultimately to contralateral inferior colliculus of the midbrain
Inferior Colliculus
involved in hearing, integral portion of auditory pathways in CNS
Neurons conducting impulses from the structures of the inner ear to the brain all synapse in inferior colliculi
Medial Geniculate
Receives and processes auditory info. Part of thalamus. Diencephalon
primary auditory cortex (A1)
the main area of cortex which first processes auditory
information in the brain, situated on the inferior surface of the lateral sulcus
Heschl’s gyrus
The location of the brain to which all auditory information is projected.
waystations
perform complex processing incoming nerve impulses
traveling wave theory
- for each inward and outward movement 2. downward and upward movement of basilar membrane 3. wave moves down cochlear duct from base to apex 4. little is known about the development of the auditory nerve and CANS
high frequency
basal end of cochlea only
low frequency
apical end of cochlea and all through
how are humans capable of frequency discrimination
auditory nerve fibers are sharply tuned
are spacing between nerve fibers equal?
no
vestibular
informs brain about head movement and helps maintain balance
found in the inner ear
contains the semicircular canal, utricle, and saccule
what is a decibel
1/10th of a Bel
unit of measurement of intensity used in acoustics and audio metrics
5 important aspects of a decibel
- involves ratio 2. uses a logarithm 3. nonlinear 4. may be expressed in terms of various reference levels 5. relative unit of measure
what are the essentials for sound to be created and heard?
- vibration 2. force 3. medium (gas, fluid, or solid) 4. hearing mechanism to receive and perceive energy of the soundwave
