12-4 Audition Flashcards
A: In the OUTER ear the ___ & ______ direct sound/vibrations to tympanic membrane
B: Once in The MIDDLE ear _______ conduct sound from the tympanic membrane to the ___ _____
C: What does the EUSTACHIAN Tube do and where is it located?
A: In the OUTER ear the Pinna & [EAM Ear Canal] direct sound to the tympanic membrane
B: The MIDDLE ear [MIS ossicle bones]–>{Stapes/Incus/Malleus} conduct sound from the tympanic membrane to the [Oval vestibular window]
EAM = External Auditory Meatus
A: Cochlea
B: Perilymph [2]
ºsecreted by ___ ____ & __ ____
ºSimilar to __ fluid with ___(high/low) [Na+ and Cl- ]
ºFlows in [_____ duct] toward the _____ space
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C: EndoLYMPH
ºSecreted by [__ ____] but requires ___ using ___ pump
ºUsually ___ (high/low) [Na+ and protein] and has net mV of ____
ºFlows in [____ duct] toward the __ ____ sac
D: Where are both of these located?
B: Perilymph =
ºsecreted by [scala tympani & scala vestibuli]
ºSimilar to interstitial fluid with high Na+ and Cl-
ºFlows in [perilymphatic duct]—>subarachnoid space
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C: EndoLYMPH=
ºSecreted by [Stria Vascularis] but requires ATP using Na+/K+ pump
ºUsually low Na+ and protein with net mV of +80
ºFlows in [endolymphatic duct]—>[subdural endolymphatic sac] (where it’s reabsorbed into blood)
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D: BOTH IN INNER EAR
A: Sound Waves are made by ______
B: What is the Frequency auditory range for humans? What is Intensity based on?
A: Sound Waves are made by Air Pressure Oscillations above and below atmospheric pressure.
B: Freq. range of human auditory= 15Hz - 20kHz (BEST in 1-5 kHz). Intensity of Sound is based on Amplitude of Oscillations
A: How is the {L-shaped lever arm} of the Middle Ear Formed?
C: Where is the Tensor Tympani m. & what is it innervated by?
D: Where is the Stapedius m. & what is it innervated by?
D2: What is the OVERALL PURPOSE of these 2 Middle ear muscles?
E: What is the purpose of the [MIS Ossicle bones]
A: [Malleus] is attached to Tympanic Membrane on 1 end and then fuses with the [Incus] on the other= {L-shaped lever arm}
C: Tensor Tympani m.= Fast Striated m. (middle ear wall fibers) near eustachian tube that attaches to Malleus
{{Innervated by CN5B3}}
D: Stapedius m.= Fast Striated m. (middle ear wall fibers) tht attaches to [Stapes] near its connection with [Incus]
{{{Innervated by Facial CN7}}}
E: [MIS Ossicles bones] improve [air pressure oscillation TRANSFERENCE] from air —> [peri/endoLYMPH] by amplifying {air pressure oscillations} x20
A: [Bony Labyrinth] is the __-SHAPED CAVE of the ____ ear that surrounds a bony core called the _______. It’s housed in the ____ _______ bone and has a [_____ Snail Apex]. The [Bony Labyrinth] is divided into 3 canals.
B: These 3 Canals are separated by the ____ ___ _____ & ____ ___.
C: Describe These 3 Canals
A: [Bony Labyrinth] is the SNAIL-SHAPED CAVE of the INNER ear that surrounds a bony core called the [MODIOLUS]. It’s housed in the Petrous temporal bone and has a [Helicotrema Snail Apex]. [Bony Labyrinth] is divided into 3 canals.
B: 3 Canals: [Scala are separated by [Reissner’s Vestibular Membrane] & basilar membrane]
1. Scala Vestibuli (Contains perilymph & is continuous with bony labyrinth of vestibular apparatus)
- Membranous Labyrinth (inbetween 2 Scala)
- Scala Tympani (Contains perilymph and separated from Cochlear Duct by Basilar membrane in the round window)
A: [Membranous Labyrinth] is filled with ______ & forms the ___ ____ (or ___ ____) which contains [________]. This is where __________
B: How far does the Cochlear Duct extend throughout the cochlea in the [Membranous Labyrinth]?
C: In the [Membranous Labyrinth] what separates the Scala Vestibuli from Cochlear Duct ?
A: [Membranous Labyrinth] is filled with ENDOLYMPH & forms the COCHLEAR DUCT (or scala media) which contains [Organ of Corti]. This is where sound wave transduction—>nerve impulses occur.
B: Cochlear Duct extends throughout the cochlea, EXCEPT FOR HELICOTREMA
C: [Reissner’s Vestibular Membrane] separates Scala Vestibuli from Cochlear Duct
A: Sitting on the Basilar Membrane is the ______. This membrane Extends from _____ to ______
B: On the [Outer Cochlear DUCT Wall] you’ll find the ___ _____ which secretes _____ into _______ duct
A: Sitting on the Basilar Membrane is the [Organ of Corti]. This membrane Extends from [Spiral Lamina] to [Outer Cochlear Wall]
B: On the [Outer Cochlear DUCT Wall] you’ll find the [Stria Vascularis] which secretes endolymph into Cochlear DUCT
A: [Peri/endoLYMPH] are ____ fluids that when oscillated stimulate ___ ____ cells—>travel in ___ ___ ___
—->_______ into nerve impulses in the __ ___ ____
B: Describe the Flow of PeriLYMPH (3)
C: Describe the flow of endolymph (3)
A: [Peri/endoLYMPH] are cochlear fluids that when oscillated stimulate cochlear hair cells—>travel in cochlear nerve fibers—->vibrations into nerve impulses in the [Organ of Corti]
C: endolymph flows into membranous labyrinth of Vestibular Apparatus –>and then (via ENDOlymphatic Duct)—>subDural endolymphatic sac and reabsorbed into blood
1) The [Organ of Corti] contains __inner row and __ OUTER rose of hair cells. Describe each of these rows (OUTER vs. inner row)
2) What are Stereocilia
3) What supports these hair cells physically?
[Organ of Corti] contains 1 inner row and 3 OUTER ROWS of [hair cell cilia]
*OUTER ROW= insert into tectorial membrane & receive inhibitory inputs via olivocochlear n. fibers
- inner row= move in endolymph between [Organ of Corti] and tectorial membrane –>TRANSDUCTS MOST OF SENSORY AFFERENT
- 2) Stereocilia= [Tethered Hair cell cilia] arranged in a “V” and when 1 is bent –> causes neighboring Stereocilia to bend
3) Cuboidal & Columnar cells lie adjacent to these hair cells to support them
A: Inward & Outward Oscillatory movements of the ___ window are caused by __ __ __–> and result in opposite movements inside the ____ window. These Oscillations cause pressure to INC/DEC in [Scala Vestibuli]
B: Explain what Pressure change in [Scala Vestibuli] is transmitted to and How it gets there
C: How is a Tonotopic Map formed?
D: Where does this all occur?
A: Inward & Outward Oscillatory movements of the Oval window are caused by MIDDLE EAR OSSICLES–> and result in opposite movements inside the ROUND WINDOW. These Oscillations cause pressure to INC/DEC in [Scala Vestibuli]
B: Pressure change in [Scala Vestibuli]—>transmitted through [Reissner’s vestibular Membrane]—>[Scala Media Cochlear Duct]
C: Pressure change in [Scala Media Cochlear Duct] causes basilar membrane to move up and down —-> [TONOTOPIC MAP]
D: THIS ALL OCCURS IN THE COCHLEA
A: Depolarization is a function of _____ MEMBRANE movement. Oscillating movement of this membrane causes back&forth _____ movement of __ ___ ____
B: [___mV endolymph potential] and [___ mV intracell hair cell potential] –> ___ mV gradient across ____ hair cell = Normal Functioning
C: movement of inner hair cell cilia are amplified by what and how?
D: How does Hair Cells DEpolarize and Hyperpolarize?
E: What happens when a Hair cell DEpolarizes?
A: Depolarization is a function of BASILAR MEMBRANE movement. Oscillating movement of this membrane causes back&forth shearing movement of [stereocilia Hair cell cilia]
B: [+80 mV endolymph potential] and [-70 mV intracell hair cell potential] –> 150 mV gradient across apical hair cell = normal function
C: Movements of the inner hair cell cilia are amplified by OUTER HAIR CELLS which contract in phase with pressure oscillations
D:
- When Stereocilia are moved TOWARD kinocilia —>hair cell cilia K+ permeability INC = hair cell DEpolarizes
- ————————————————————————————- - When Stereocilia are moved away from kinocilia—>hair cell cilia K+ permeability decreases= hair cell hyperpolarizes
E: When DEpolarization occurs –> allows Ca+ into cells–> release of NTS glutamate–>causes depolarization (via [AMPA-type receptors]) of cochlear n. fiber–>INC action potential to CNS
Factors affecting freq. discrimination:
A: Hair Cell Cilia near Oval Window respond more to ____ frequencies and are __ in length. Why is this?
B: Hair Cell Cilia near helicotrema respond more to ____ freq and are ____ in length. Why is this?
Factors affecting freq. discrimination:
A: Hair Cells near Oval Window respond more to HIGHER freq. and are SHORTER in length –> this is becuz higher freq. transmit better thru the narrow stiff [basilar membrane] near Oval window
B: Hair Cells near helicotrema respond more to looowwerr freq. and are looonnger in length —> this is becuz this part of [basilar membrane] is wiiddder and more distensible
1) The Olivocochlear Efferent System ____ responses from selective ___ cells and consist of fibers from ___ and ______ nuclei .
This system makes _____ synaptic connections with ___ cells in ________ and ________
2) Which type of cilia are near the helicotrema and how is this related to frequency?
1) The Olivocochlear Efferent System ATTENUATES responses from selective hair cells and consist of fibers from both Contralateral and ipsilateral [SUP Olivary nuclei].
This system makes INHIBITORY synaptic connections with hair cells in [OUTER ROW—>controls amplifying effects] and [cochlear afferent terminals of inner row]
2) Longer cilia are near helicotrema and move better with loooowwwer freq.
Describe the Peripheral Auditory Pathway [2]
1) Bipolar neurons of [Spiral Ganglion] (located inside bony modiolus] send peripheral branches to innervate cochlear hair cells.
2) Central branches from [Spiral ganglion neurons] course thru [internal auditory canal] as afferent fibers in cochlear n.
•Cochlear nerve fibers enter brainstem at ___ _____ and terminate in ___________
B: Ventral cochlear nucleus is ___[smaller/Larger] and it projects to to the _______ nuclei in the _____. What is the TRAPEZOID BODY?
C: dorsal cochlear nucleus terminates in the ___ and ____ nuclei
D: [inferior Colliculus] relays ____ info (via ____) to_____ nucleus in the Thalamus —->sends ______ projections to _______ where it is interpreted
E: [T or F] Auditory Cortex is sensitive to lesions and can easily —> sound discrimination problems
•Cochlear nerve fibers enter brainstem at PONTOMEDULLARY JUNCTION and terminate in [Dorsal/Ventral cochlear nuclei]
B: Ventral cochlear nucleus is LARGER and it projects to ipsilateral & contralateral [SUP olivary nuclei] in Pons. **Midline crossing of these [Dorsal/Ventral cochlear nuclei] axons = TRAPEZOID BODY
C: dorsal cochlear nucleus terminates in the [inferior Colliculus] and [lateral lemniscus nuclei]
D: [inferior Colliculus] relays auditory info (via brachium) to [Medial Geniculate nucleus] in Thalamus —->sends auditory projections to [Area 41 Heschl’s Gyri]
E: FALSE! Auditory Cortex Lesions have to be EXTENSIVE in order to affect sound discrimination
