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XXXSpeechScienceDrM
XXXSpeechScienceDrM Exam One
Question | Answer |
---|---|
What are the two SECTIONS (alsoknown as SYSTEMS) of the ear? | Peripheral and CENTRAL Auditory Systems |
What is the Peripheral Auditory System? | Outer, middle, and inner ear |
What is the CENTRAL Auditory System? | CN VIII: Vestibulocochlear, pathways to the brainstem, auditory cortex |
CNVIII, the pathways to brainstem, and the auditory cortex are parts of what? | The Central Auditory System |
The Outer, Middle and Inner Ear are part of what? | The Peripheral Auditory System |
Where is the peripheral auditory system located? | Location of the ear in the skull Petrous portion of the temporal bone 3 parts Outer ear Middle ear Inner ear |
What is located in the petrous portion of the temporal bone? | The peripheral auditory system |
Name the Ossicles | Malleus, Incus and the Stapes |
Outer Ear: | External Auditory Meatus Open at EAM, closed at TM 1/3 cartilage, 2/3 bony, S shaped, cilia, cerumen |
External Auditory Meatus Open at EAM, closed at TM 1/3 cartilage, 2/3 bony, S shaped, cilia, cerumen | Outer Ear |
The boundary between the outer and middle ear is the | tympanic membrane |
A healthy tympanic membrane looks like what? | Translucent, pearly grey membrane |
Identify 3 cartilage layers of tympanic membrane: | Outermost epithelial, middle fibrous, innermost mucous membrane |
Tympanic Membrane has how many portions and what are they? How many layers does each have? | 2 portions Pars tensa (3 layers) Pars Flaccida (2 layers) |
What are the quadrants of the tympanic membrane and what are they useful for? | 4 quadrants: provide orientation Anterior-Superior Posterior-Superior Anterior-Inferior Posterior-Inferior |
What can be found in the middle ear? | Middle Ear space Eustachian tube Ossicles Oval Window Round Window |
List boundaries of midde ear space: | Anterior wall = Eustachian tube Beneath the floor of ME = jugular bulb Roof of the ME = tegmen tympani Space on top of ME = epitympanic recess |
What is the promontory? | The promontory is a bulge created by a cochlear turn |
Where is the Promontory? | In the middle ear space. |
What is in the superior-posterior aspect of the middle ear space, and what is below it? | Superior-posterior aspect = oval window; below that is the round window (membrane covered) |
What is the lining of the middle ear space? | mucous membrane |
Describe middle ear space in terms of air pressure and 'climate.' | Dry, air-filled cavity Air pressure, which is regulated by the Eustachian tube, should = PATM |
3 functions of eustachian tube | 3 functions Pressure equalization Ventilation of the ME space Drainage |
Describe eustachian tube: | Essentially connects the ears, nose, throat 36 mm long Normally in a collapsed state; can be forced to open, tensor palatine responsible for this action |
Describe ossicles | Smallest bones in the body Always articulate with each other; collectively called the ossicular chain, held in place by ligaments |
Describe malleus | Malleus: largest connects to the tympanic membrane Can often be seen through the TM Parts: handle/manubrium, head, anterior and lateral processes |
Describe incus | Incus: articulates with the malleus via the head Parts: long process, short process, corpus |
Describe stapes | Stapes: smallest Head articulates with the incus, neck bifurcates and becomes the crura, which converge on the footplate Stapes footplate is held in the oval window of the temporal bone via the annular ligament |
What are the names of the two muscles of the middle ear? | Stapedius and tensor tympani. Tensor tympani is L O N G E R. |
About Stapedius: CN VII | Stapedius 6 mm long , embedded in the bone of the posterior wall of the middle ear Inserts into the neck of the stapes; contraction rotates the stapes posteriorly Innervation: stapedial branch of CN VII |
About Tensor Tympani: CNV | Tensor Tympani 25 mm long; arises from the anterior wall of the middle ear, inserts into the upper manubrium of the malleus Innervation: CN V |
Stapedius and Tensor Tympani serve a protective function in what way? | They dampen sound after a loud noise is already heard... |
What are the two systems of the Inner Ear? | 2 Systems Vestibular System Cochlear System |
What are the three parts of the Inner Ear? | 3 Parts Semi-circular canals Vestibule: entryway to the cochlea Cochlea |
What are the two labryinths of the inner ear? | Osseous Entryway to the labyrinth, vestibule, semi-circular canals, osseous cochlear canal Membranous Houses the inner ear structures |
The two inner ear vestibuli are: | Utricle and saccule |
Th two inner ear vestibuli, the Uricle and the Saccule contain what? | They contain macula, sensory organs for balance |
In the inner ear vestibuli, the Utricle and the Saccule, there are macula. What are macula? | Sensory organs for balance. |
The inner ear vestibuli are responsible for what? | Balance. |
There are 3 semicircular canals in the inner ear vestibular portion. Describe them: | 3 Semi-circular Canals: oriented at 90o angles to each other Contain the sensory organs for movement of the body in space; balance Anterior, posterior, horizontal Orientation to each other allows the brain to code 3-dimensional space |
Apex: | Apex: innermost point of the cochlea |
Modiolus: | Modiolus: core of the cochlea |
How are scala created in the inner ear cochlea and how many are there? | Osseous and membranous portions create 3 scalae |
Scala Vestibuli | Scala Vestibuli: Roof: bone, floor: Reissner’s membrane Filled with perilymph, a fluid high in Na, low in K Contains Oval Window |
Scala Media (Cochlear Duct): | Scala Media: Roof : Reissner’s membrane, floor: basilar membrane Filled with endolymph, a fluid low in Na, high in K Also called the “cochlear duct” |
Scala Tympani | Scala Tympani: Roof: basilar membrane, floor: bone Also filled with perilymph Contains Round Window |
Scala Vestibuli | Oval Window |
Scala Tympani | Round Window |
Scala Media | No window! |
Perilympth | Scala Vestibuli and Scala Tympani |
Endolympth | Scale Media / Cochlear Duct |
High in Na, low in K | Scala Vestibuli and Scala Tympani |
Low in Na, High in K | Scala Media / Cochlear Duct |
What is the end organ for hearing? | Organ of Corti |
What does the Organ of Corti sit on? | The basilar membrane. |
What is the Organ of Corti encased in? | Endolympth. |
Supportive cells near Organ of Corti are: | Deiter's Cells and Hensen's Cells |
Total rows of Inner and Outer Hair Cells combined: | four. There is only one row of Inner Hair Cells and 3 rows (W shape) of Outer Hair Cells |
Inner Hair Cells | Inner Hair cells: 3500, a single row from base to apex Each has approximately 50 stereocilia Tear-drop or gourd shaped Many nerve fibers innervate each IHC |
Outer Hair Cells | Outer hair cells: 12,000, 3 rows in a “W” pattern Each has approximately 150 stereocilia “test tube” shaped Only one nerve fibers innervates most OHC’s |
Tunnel of Corti | Tunnel of Corti Separates the 1 row of IHC’s and 3 rows of OHC’s Created by the pillar cells of Corti |
Spiral Limbus | Spiral Limbus; supports tectorial membrane Found on modiolar side of cochlear duct |
Tectorial Membrane | Tectorial Membrane; hinged on one side. Sits on top of IHC and OHC. Arises from spiral limbus Gelatinous structure (90% water) that overlays hair cells Outer hair cells are embedded in the underside Important contributor to hair cell excitation |
Stria Vascularis | Stria Vascularis One end of Reissner’s membrane, attached to spiral ligament Provides oxygen to cochlea; produces endolymph |
Supporting Cells | Supporting Cells Cells of Claudius Deiter’s cells Hensen’s cells |
Tectorial membrane makes contact with sterocilia of which hair cells? | Tectorial membrane makes contact with stereocilia of Outer hair cells only. |
Where is the stapes footplate situated? | Stapes footplate is seated right in the oval window in scala vestibuli. |
Impedence Mismatch | Originally sund travels through air, but when stapes footplate moves in oval window, the perilympth in scale vestibuli starts to move TOO. The medium in which sound NOW TRAVELS IS LIQUID. |
When does the sound stop traveling through air and start traveling through a liquid? | Up until the oval window where the stapes causes the cochlea's perilympth in the scala vestibuli to move - now sound through LIQUID |
Energy travels more easily through air because air is | LESS DENSE |
Water has more impedence because of | water has increased density as compared to air |
Impedence Mismatch affects intensity of sound, loudness, dB in what way? | The change of medium of Air to Liquid causes a decrease in sound intensity. dbSPL. In fact,., you lose about 30 db right off the bat. |
What attributes about the ossicular chain help bring back the intensity of a sound after impedence mismatch? | Ossicular chain always moves as ONE UNIT. Moves as 3 bones together and results in increased force. Ossicles act as levers… TM pushes on oval window with ossicular chain in between. TM is bigger than oval window and bigger pushes HARD. |
Movement of Perilymph causes what? | Movement of Reissner's membrane |
Movement of Reissner's membrane causes what? | Movement of the Endolymph |
Movement of the Endolymph causes what? | Movement of the Basilar membrane |
Movement of the basilar membrane causes what? | Movement of the perilymph in Scala Tympani |
Movement of the perilymph in the Scala Tympani causes what? | Pushing against the round window which then makes the movement cycle reverse. |
The cochlea is encased in what? | Bone |
Are the fluids in the cochlea compressible? | No - the cochlea is encased in bone. |
How can perilymph move between the scala vestibuli and the scala tympani? | Through the helicotrema. |
Do Endolymph and Perilymph ever mix? | No. |
Which window is membrane covered? | The round window. |
Is the oval window membrane covered? | No - the stapes footplate sits securely in the oval window like a carved pumpkin top. |
The BASE is by the middle ear. How can you determine the Base? | Close to middle ear and has round and oval windows and hears high frequencies |
What landmark is close to the APEX? | The APEX is over by the Helicotrema! Low Frequencies! |
When sound occurs, both Reissner's Membrane and the Basilar membrane are displaced causing | movement which impacts the Organ of Corti which then moves in an up and down motion. |
Describe the Basilar Membrane: | narrow, thin, and stiff at the base near the middle ear and round and oval windows; Wider and Thicker Mass at the Apex near the helicotrema. |
Basilar Membrane | Narrow, thin, and stiff at the base; wider and thicker mass at apex. |
Mass-stiffness gradient | Stiff at base; Mass at Apex |
Apex: | Wide, thick, mass, low frequencies, by helicotrema |
Base: | Narrow, thin, stiff, high frequencies, by windows and middle ear |
Mass-stiffness gradient | stiffness at base, mass at apex |
The basilar membrane is a filter because | the base registers high frequencies and the apex registers low frequencies |
Another word for low frequencies | resonance |
When the Basilar Membrane moves, so does the | Organ of Corti |
The tectorial membrane is like a lid and the pivot point is the | hinge |
How much the basilar membrane moves has to do with | the intensity of sound coming in More robust reaction to greater sound. |
Movement of the Basilar membrane causes what kind of Action? | Movement of the Basilar Membrane causes a Shearing Action. |
What is impacted by the shearing action caused by movement of the basilar membrane? | The inner and outer hair cells are impacted by the shearing action of the basilar membrane movement. |
What does shearing action cause? | Shearing action causes a change in the resting potential of the neurons. |
When the resting potention of the neurons is changed by shearing action, what happens to the hair cells? | The become depolarized. |
When the hair cells become depolarized from the shearing action of the basilar membrane, what happens with regard to action potential? | The shearing action causes the hair cells to become depolarized and this results in a change in action potential. |
When there is a change in action potential due to shearing action, what happens in the nerve? | A change in action potential causes an impulse to travel up the CNVIII nerve to the brainstem to the auditory cortex. |
The action potential is the firing of the neurons in what part of the auditory system? | The Organ of Corti because it impacts hair cells. |
Nerve cells are connected to | hair cells |
When you get shearing of the stereocilia, you get | firing of the neurons in the inner ear |
Prior to firing, the neurons are at | rest |
Shearing action causes neurons of the inner ear to | fire |
The neurons are either firing or they are not, it is like a | switch; either at rest or firing |
The neurons together form | spiral ganglion |
Spiral ganglion turns into which CN nerve? | Spiral ganglion turn into CNVIII; they bundle up and travel to the brain. |
What is the opposite of polarization? | Depolarization |
The Traveling Wave | frequency components travel a shorter or longer distance on the basilar membrane depending on the frequencies in a complex sound. |
The outer hair cells are farthest away from the | pivot point |
The number of oscillations of the TM-Ossicle-Footplate movement per second | Frequency |
If at the level of the inner ear the stapes footplate moves in and out of oval window 100 times per second then the frequency is | 100Hz |
Traveling Wave separates what? | the frequency components of complex sounds |
High frequency sounds cause vibration near what part of the cochlea | cochlea base |
Low frequency sounds cause vibration near what part of the cochlea | cochlea apex |
Which of the traveling waves travel the furthest | low frequency sounds travel farther as they cause vibration near the apex. |
Where does the Traveling Wave travel | along the Basilar Membrane |
As the Traveling Wave travels along the Basilar Membrane how does it change | the Traveling Wave grows and swells crests at a certain point then damps down right after – like an ocean wave |
What does the Traveling Wave separate | frequency components of complex sounds |
What are the two modes of hearing | Air Conduction and Bone Conduction |
Sound travels through the Outer Middle and Inner Ear and then on to Cortex via | Air Conduction |
When sound directly stimulates the cochlea this is known as | Bone Conduction |
When the skull is vibrated setting the cochlea this is an example of | Bone Conduction |
When sound completely bypasses the Outer and Middle Ear this is an example of | Bone Conduction |
Helicotrema is | Apical End |
Low Frequencies peak at the | Apical End |
Base is closest to | Inner Ear |
High frequencies peak at | Base |
All sound goes to | Organ of Corti |
Primarily when we are talking to ourselves we hear through | Bone Conduction |
Primarily we hear things in the world through | Air Conduction |
With a particularly loud sound we hear it through | Air and Bone Conduction |
If there is fluid in the middle ear sound gets | damped down |
With fluid in the middle ear there is a reduction in | intensity or loudness |
The lowest intensity sound the ear can detect 50% of the time are the | Hearing Thresholds |
Hearing Thresholds want to test | the limits of the ear’s abilities to hear |
Hearing Thresholds are different for | Different Listeners |
True or False Hearing Thresholds are the same for all listeners | False; hearing thresholds are different for different listeners |
Hearing thresholds are used to represent degrees of | hearing loss |
Does Impedence Mismatch occur with bone conduction | No |
Normal Hearing | 0 – 15 dBHL |
Borderline Normal for Children | 16 – 25 dBHL |
Good hearing is crucial for children as they are | still learning language |
A child with a slight degree of hearing loss in Kindergarten is at risk for | problems in school |
Noise level in a Kindergarten classroom is 90dB like a | vacuum cleaner |
A hearing loss in a child may be undetectable | at home; but significant in a school setting |
If a hearing threshold is 90 can someone hear a sound at 85 dBHL? | No they cannot; 90 dBHL is the lowest sound they can hear. |
Conductive Hearing Loss | problem is in Outer or Middle Ear |
With a Conductive Hearing Loss there is a loss by | Air Conduction |
With a Conductive Hearing Loss there is | Loss by Air Conduction and NORMAL hearing by bone |
With a Conductive Hearing Loss you have the presence of | an air-bone gap |
With a Conductive Hearing Loss | there is ‘flat’ or ‘low frequency’ configuration |
With a Conductive Hearing Loss | sounds are quiet as with earplugs in |
People with a Conductive Hearing Loss may | talk LOUDER |
Conductive Hearing Loss is treatable with | medication or surgery |
With a Conductive Hearing Loss the problem is | getting the sound by air TO the cochlea |
With a Conductive Hearing Loss a bone-conduction test would have | normal results |
With a Conductive Hearing Loss an air-conduction test would show | hearing loss |
Middle Ear Infection | Conductive Hearing Loss |
Otitis Media | Middle Ear Infection = Conductive Hearing Loss |
Otitis Externa | Swimmers Ear = Conductive hearing loss |
Tympanic Membrane Perforation | Conductive Hearing Loss |
Impacted Cerumen | Conductive Hearing Loss |
Ossicle trauma | ossicular disarticulation |
Ossicular Disarticulation | Conductive Hearing Loss |
Any way there is a problem with conduction of sound TO the cochlea | Conductive Hearing Loss |
Hearing Threshold respresents | the lower limit of what the ear can hear |
We need to know the softest sound the ear can hear at | various frequencies |
Lowest frequency is | 250 Hz |
Octave doubling in frequency for | testing the various frequencies we can hear |
Octaves for tests 250 Hz 500 Hz | We test at 250 Hz to 8000 Hz |
We use pure tones to find out what thresholds are across a range of | frequencies |
Different points on the basilar membrane correspond to | different frequencies |
Different frequencies that the basilar membrane responds to depend on where | the wave peaks |
A 250 Hz wave peaks | at the apex |
A 250 Hz wave is a low frequency | this means it peaks at the apex near the helicotrema and travels a LOOOONG way across the BM |
An 8000 Hz wave peaks at the base near the middle ear | |
We test octave frequencies to | stimulate different point on the BM to see how hearing works across the board |
Most sounds in the world are not | pure tones |
Different sounds have different | acoustic blueprints |
If there is a loss and where it might be frequency-wise | could result in a person not being able to hear CERTAIN phonemes |
As the thresholds get HIGHER | hearing gets WORSE |
You want the threshold to be | as low as possible |
Normal hearing has a threshold of | 0 – 25 |
X axis on a hearing chart is | frequency in Hz |
An octave is a doubling in frequency | 250 – 500 1000 – 2000 |
True or False There is one threshold per frequency per ear | True |
Y axis on hearing chart is | hearing level in dBHL (decibels) |
Is the person’s hearing loss higher or lower for certain | frequencies |
Is the person’s majority of their hearing happening at the | apex or base |
Right Red Round | threshold for right ear |
Anything higher than the threshold is something | you CAN hear |
Sensorineural Hearing Loss | an abnormal function in the inner ear |
Sensorineural Hearing Loss | equal amount of hearing loss by air conduction and bone conduction |
Sensorineural Hearing Loss | No air-bone gap; amount of hearing loss is equal for air and bone |
Sensorineural Hearing Loss | “high frequency” configuration |
Sensorineural Hearing Loss | sounds are perceived as DISTORTED AND QUIET |
Sensorineural Hearing Loss | people talk LOUDLY |
Sensorineural Hearing Loss | generally not reversible |
Fricatives are a | complex aperiodic high frequency wave |
If a hearing chart shows high thresholds for high frequencies | person cannot hear Fricatives /f/ |
If the hearing chart emphasizes a loss for high frequency waves | it would impact perception |
If the hearing chart emphasizes a loss for high frequency waves | it won’t affect person’s speech |
If the hearing chart emphasizes a loss for high frequency waves in a child learning language | it will affect speech for child as well as the child’s perception of the speech of others |
Mixed Hearing Loss | components of both conductive hearing loss and sensorineural hearing loss |
Mixed hearing loss | loss by both air conduction and bone conduction although worse by air |
Always worse | by air |
Mixed Hearing Loss | presence of air bone gap |
In a Conductive Hearing Loss | bone conduction is normal |
In a Mixed Hearing Loss | loss by bone and by air |
Mixed Hearing Loss | problem in outer |
Problem in outer and middle is greater because the thresholds are worse than | bone |
When are thresholds are Higher than bone thresholds | you have an air-bone gap |
We always test air conduction | first |
If Bone conduction was normal and air conduction threshold was impacted | Air-Bone Gap |
Air – Bone Gap | 15dB=air-bone gap |
Bone conduction is always | better |
A loss by air with normal bone | conductive loss |
Sound has to ultimately end up at the | cochlea to be detected |
When you test by bone you send sound directly to the | cochlea |
When you test by air | you send sound to the outer middle and inner ear |
Central Auditory Processing Disorder | interference in pathways from brainstem to cortex |
CA Processing Disorder | Central Auditory Processing Disorder |
Central Auditory Processing Disorder | when the peripheral auditory system is intact |
Central Auditory Processing Disorder | normal hearing thresholds by air and bone but can’t make sense of it |
Central Auditory Processing Disorder | can’t make sense of what is heard can manifest as a speech and language disorder |
Conductive hearing loss is temporary | we can do something about it |
Pathologies of the outer ear | agenesis |
Pathologies of the external auditory canal congenital causes | stenosis |
Pathologies of the External Auditory Canal | otitis externa (swimmers ear) bacterial |
Impacted cerumen | blockage of ear wax in entire canal |
Middle Ear Pathologies | otitis media due to Eustacian Tube |
Cerumen Atresia and Otitis Externa | are OUTER EAR CAUSES |
Otitis Media | fluid in middle ear due to eustacian tube childhood illness #1 |
Conductive hearing loss causes | impacted cerumen |
Any problem in outer or middle ear | conductive hearing loss |
Gap = | 15Hz or more between air and bone |
Degrees for loss by air and bone are the same | 0-25 |
26-40 | mild hearing loss |
Tempanic Membrane Perforation | Conductive Hearing Loss |
Damage to Inner Ear | sensorineural loss |
Sensorineural | loss by bone and by air but no gap because both air and bone are impacted equally |
Sensorineural loss | problem is 8th nerve and cochlea |
Mixed Hearing Loss is worse | by air |
Cause of sensorineural hearing loss | concert loud noises causes death of hair cells |
Sensorineural hearing loss is | permanent can’t fix it with meds or surgery |
Middle Ear Otosclerosis | abnormal growth of spongy bone on stapes footplate |
Middle Ear Ossicular discontinuity | break in ossicular chain often due to head trauma |
Inner Ear noise induced hearing loss | can be temporary or permanent |
Meniere Disease | endolymphatic hydrops too much or too little endolymph in cochlea |
Ototixicity | temporary or permanent cochlear or vestibular |
Presbycusis | hearing loss due primarily to aging |
Ototoxic drugs kill | outer hair cells first |
If drugs attack the outer hair cells first which frequencies are lost first | highest frequency sounds then lower ones |
Mixed loss means | outer and inner such as impacted cerumen and prebycusis |
Central Auditory Processing Disorder | doesn’t have to be just CNVIII |
Central Auditory Processing Disorder | hearing test is fine but can’t understand in a background of noise |
Cochlear Nucleus to | Superior Olivary Complex to Lateral Lemniscus to the Inferior Colliculus |
Lateral Lemniscus is in the | Pons region |
Cochlear Nucleus to Superior to Lateral to Inferior | |
Connected fibers allow crossover between the two | inferior colliculi |
Central Auditory Mechanism | sound starts off as a physical even and ends up as a neural representation of the physical properties of sound |
Central Auditory Mechanism | becomes an electrical impulse that travels up to the brain |
CN VIII | vestibulocochlear |
What are the 2 Branches of CNVIII | Auditory and Vestibular |
CN VIII runs with | CN VII in the internal auditory meatus |
CN VII | facial |
CN VII first reaches | the cochlear nucleus 1st major nucleus of the auditory system |
After CN VIII reaches the cochlear nucleus | the info is carried all the way to the cortex |
Afferent Pathways | Afferent = Ascending |
CN VIII afferent fibers terminate in the | cochlear nucleus a part of the medullal |
2 accending pathways: Ipsilateral and Contralateral (Contralateral is opposite side as stimulated cochlea) | |
Decussation | crossing over of nerve fibers from one side of pathways to the other side |
Afferent goes | up |
Sound can come in left ear and travel in right contralateral pathway in addition to | ipsilateral pathway |
When the sound crosses over it is called | decussation |
During decussation | it is nerve fibers that are crossing over |
2/3 of the nerve fibers from the cochlear nucleus decussate with the Superior Olivary Complex | |
The Superior Olivary Complex is the next major nucleus in the CANS | |
Trapezoid Body | neural tract that crosses the brainstem |
1/3 of nerve fibers reach the Superior Olivary Complex | on the Ipsilateral Side |
Cochlear Nucleus to | Superior Olivary Complex to Lateral Lemniscus to the Inferior Colliculus |
Lateral Lemniscus is in the | Pons region |
Cochlear Nucleus to Superior to Lateral to | Inferior |
Connected fibers allow crossover between the two | inferior colliculi |
Trapezoid body | is a tract is a path |
Sound comes in right and travels up right it is | ipsilateral |
When sound crosses over it is | contralateral |
Medulla and Pons | brainstem |
Between cochlear nucleus and superior olivary complex | 1st point of decussation |
What do you call this first point of decussation | trapezoid body |
2/3 of the fibers go contralateral | 1/3 go ipsilateral |
Some fibers bypass the inferior colliculus and go to the next nucleus | medial geniculate body in thalamus |
Finally tract fans out into auditory radiations from the | medial geniculate body to the auditory cortex in the temporal lobe of brain |