Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Bony Labryinth
| Question | Answer |
|---|---|
| Bony, osseous portion of labyrinth is embedded in ______ portion of temporal bone | petrous |
| Main purpose of bony labyrinth to provide _____ and ______ | support, protection |
| Osseous Vestibule-Anterior=______ and posterior= ________ ________ | cochlea, semicircular, canals |
| The vestibule is _____ in shape, lateral wall forms _____ wall of middle ear cavity, contains oval window | ovoid, medial |
| Vestibular Aqueduct extends to posterior surface of ______ bone | temporal |
| The _______ _______ (membranous) terminates in dura mater | Endolymphatic, Duct |
| Osseous Vestibule forms _____ _____ of bony labyrinth | central, portion |
| Osseous Vestibule is _____ in shape | ovoid |
| Osseous Vestibule lateral wall contains ____ _____ | oval, window |
| Osseous Vestibule medial wall contains opening of _______ ______ | vestibular, aqueduct |
| Osseous Vestibule, Vestibular Aqueduct-the bony channel that contains the ______ ______ | endolymphatic, duct |
| Vestibular Aqueduct courses from the wall of the ______ to the ______ ____, located on the posterior surface of the ______ bone | vestibule, endolymphatic, sac, temporal |
| Osseous Vestibule is considered to be part of the vestibular portion of the inner ear because it houses the _____ and _____, which have vestibular function | Utricle, Saccule |
| Osseous Vestibule contains two distinct depressions: _____ Recess, where ______ is located, and _______ Recess, where _____ is located | Elliptical, Utricle, Spherical, Saccule |
| Three Osseous Semicircular Canals: ______ (anterior) _________ and ________ (horizontal) | Superior, Posterior, lateral |
| Osseous Semicircular Canal-Each canal contains a dilation called an _____ where the canal joints the vestibule | ampulla |
| Osseous Semicircular Canal- The superior (anterior) and posterior canals join to form a _____ ____ which opens into the vestibule | common crus |
| The semicircular canals lie in three planes, perpendicular to one another-any two forming nearly a ____ _____ | right, angle |
| Osseous Cochlea-Located in the _____ portion of the temporal bone immediately medial to the _____ ______ | petrous, tympanic, cavity |
| Osseious Cochlea-resembles a snail shell and has about 2 __/__ turns, these turns are smaller at the ____ than at the ____ | 5/8, apex, base |
| Modiolous: A central, _____ bony core that accommodates nerve fibers from the hair cells, as well as blood vessels | perforated |
| Modiolous: Continuous with the internal auditory meatus at the ____ end | medial |
| Modiolous- the central structure around which the ______ is wrapped | cochlea |
| Osseous Spiral Lamina-A shelf like structure that winds around the ________ from base to apex | modiolous |
| Osseious Spiral Lamina-Composed of two thin plates between which auditory nerve fibers pass from the hair cells in the cochlea to the spiral ganglion to form the _____ _____ | auditory, nerve |
| The perforations in the osseous spiral lamina that accommodate the nerve fibers are called ________ | habenulaperforata |
| Spiral Lamina is narrower at the ____ than at the ___ of the cochlea | apex, base |
| Osseous Spiral Lamina-The upper shelf of spiral lamina is continuous with ____ ______ | spiral limbus |
| The spiral limbus serves as an attachment and support point for the _____ membrane | tectorial |
| Openings of the bony cochlea-Oval Window-more _____ of the two openings | superior |
| Oval Window interacts with the ___ of the middle ear and opens into the ________ | stapes, scalavestibuli |
| Openings of the bony cochlea-Round Window-______ to the oval window | inferior |
| Round window opens into the ____ _____ | scala tympani |
| Round window is covered by a membrane that retains _____ fluids within the ______ | cochlear, cochlea |
| ______ is positioned between the oval and round windows | Promontory |
| Osseous Cochlear Aqueduct-contains ________ and courses from the basal turn of the ______ _____ (near the round window) to the ______ space near the ____ _____. | perilymph, scala, tympani, subarachnoid, jugular, fossa |
| Osseous Cochlear Aqueduct-Allows transfer of _______ fluid | cerebrospinal |
| Helicotrema- at the apex of the ______ | cochlea |
| Helicotrema is the ONLY point of communication between ______ and _____ ____ | scalavestibuli, scala, tympani |
| Helicotrema - Near the apex, the spiral lamina terminates as a ___ like process called the _______, which assists in forming the boundary of the helicotrema | hook, hamulus |
| Internal Auditory Meatus (IAM) bony canal that houses: Facial, auditory, and vestibular nerves and portion of ______ artery | basilar |
| IAM carries nerve bundles to the ______ from the cochlea | brainstem |
| IAM can be divided into four quadrants when viewed at the opening where the nerve fibers begin their ascent to the _______ | brainstem |
| A cross-section of IAM will reveal: Upper left area of IAM contains ____ nerve. Inferior to the facial nerve is the _____ portion of the 8th nerve | facial, auditory |
| IAM: Superior and inferior quadrant houses the nerve fibers from the _____ and ______ Vestibular Portion of the VIIIth nerve | Superior, Inferior |
| Membranous Labryinth follows the bony labyrinth and has three divisions: ______ _______ (Vestibular System, for equilibrium or balance), ______ and _____ (vestibular system), and _____ _____ (i.e. scala media) (system for hearing) | Semicircular Canals, Utricle, Saccule, Cochlear, Duct |
| Membranous Cochlea follows the ____ shape of the bony cochlea from base to apex | spiral |
| Three scalae within the cochlea: ________ (superior), ____ _____ (ie cochlear duct) located in the middle and | Scala Vestibuli, Scala Media, Scala Tympani |
| Membranes that separate the scalae: _____ ______ and ______ ______ | Basilar Membrane, Reisner's Membrane |
| Basilar Membrane: connected to the _____ ligament on the outer wall of the bony cochlea and to the ______ ______ ______ | spiral, osseous spiral ligament |
| Basilar Membrane: 1. Forms the floor of the _____ _____ 2. Stiffer at the ____, more flaccid at the _____ 3. Narrow at the ____ , wider at the _____ | scala media base, apex base, apex |
| Reissner’s membrane – forms the ____ of the cochlear duct (scala media) and the floor of the ____ _____ | roof, scala vestibuli |
| Membranous Communication Ducts: ______ ______ and _____ _______ | Ductus Reuniens, Endolymphatic Duct |
| Ductus Reuniens – a ______ duct that communicates from the basal region of the _____ with the saccule of the vestibule | membranous, cochlea |
| Endolymphatic duct – mem. duct housed within the _____ ______ ______ 2. ED contains ______ 3.Courses from the vestibule to the ____ ______, located on the posterior surface of the temporal bone 4.ED is thought to help regulate endolymphatic pressure | Osseous Vestibular Aqueduct, Endolymph, endolymphatic sac |
| Cochlear Fluids: ______, _______, and ________ | Perilymph, Endolymph, and Cortilymph |
| Perilymph – similar to _____ ______ in ____ composition. High in____ (Na-), low in _____(K+) Fills the SV and ST Also fills the _____ space between the osseous portion and membranous portion of the vest and semicircular canals | cerebrospinal fluid, ionic composition, sodium, potassium, perilymphatic |
| ii. Endolymph – similar in ionic composition to ______ ______1. High in _____, low in ______ 2. Fills the ____ ______ (cochlear duct) & membranous portion of the vestibular system (utricle, saccule & SSC) | intracellular fluid, potassium, sodium, scala media, |
| Cortilymph – similar in ionic composition to _______ fluid (very similar to perilymph) 1. High in _____, Low in ______ 2. Fills between the _____ cells (within tunnel of Corti) and around the base of hair cells in the cochlea | perilymph, sodium, potassium, pillar |
| Scala Media 1.Houses the sensory organ for hearing: the Organ of ______ 2.Organ of Corti – lies on top of the ______ membrane (Runs the length of the cochlear duct and consists of supporting structures, sensory cells and nerve fibers) | Corti, Basilar |
| Tectorial Membrane – situated immediately above the organ of _____ and covers its entire length The ______, tips of the outer hair cells are firmly embedded in the underside of the tectorial membrane | Corti, Sterocilia |
| The relative mass and dimensions of the tectorial memb. increase from ____to apex Attached to the ____ _____ on one side and is thought to be attached to supporting cells on the other | base, spiral limbus |
| Reticular lamina – forms the _____ of the sensory and supporting cells of the organ of Corti a. Separates the ______ from the internal structures of the organ of Corti (the fluid around the cells and in the tunnel of Corti is _____) | ceiling, endolymph, cortilymph |
| RL-Formed by the phalanges of the Deiters’ and inner phalangeal cells, as well as by the inner and outer pillar cells, along with the top margin of the sensory cells (termed _____ plate) | cuticular |
| The cilia of the hair cells penetrate the reticular lamina Resulting in only the ___ of the hair cells bathed in _____ the ___ ____ forms a barrier to the endolymph compartment and separates the hair cells proper from the endolymph | cilia, endolymph, |
| e. The cilia are bathed in high-potassium concentration & hair cells proper bathed in ______ (which is similar to perilymph) | cortilymph |
| Lateral Wall of CD Spiral ligament- The outer wall of the cochlea is characterized by a thickening of the ______ known as the ______, which projects inward to form a shelflike prominence called the _____ ______ | periosterum, spiral ligament, basilar crest |
| Lateral Wall of CD-Striavascularis – supplies ____ and _____ to the cochlea and may manufacture ______ | blood, nutrients, endolymph |
| Sensory Hair Cells-Inner HC Single row on BM _____ cells _____ or flask-shaped Have more mito. than the OHCs | 3500, ovoid |
| Sensory hair cells-Inner HC-The stereoc. (on top of cuticular plate) Arranged in __ rows Are a ___-shape pattern on top of the hair cell Are not embedded in the tect. membrane | 3, U |
| Outer Hair Cells- __ to __ rows on BM (about _____) ______-shaped Contain _______ proteins (e.g., actin, myosin, prestin, etc) Allows for expansion and contraction of the hair cells | 3, 5, 12,000, contractile |
| OHC have both a _____ and sensory response to stimulation iv. The stereocilia (on top of the cuticular plate that anchors them) are attached to the underside of _____ _______ There are __ rows of stereocilia on each cell 2. Form a __shape on each OHC | motor, Tectorial M, 3, W |
| ______ – is the tallest of the stereocilia for each hair cell (though not always present in the cochlea) ii. Stereocilia have pores that open upon excitation (_____ ) allowing ___ ions into the cell | Kinocilium, depolarization, K+ |
| Contain ___ ____ – fibers that connect cilia together so they move as a unit ____ _____ structures – small filaments that connect to other cilia and ion channels Connect to ______ channels and open these channels when the cilia are deflected | Cross Link, Tip Link, Mechanotransduction |
| Supporting cells Deiter’s cells: 3 main parts: ____ ____, ____ and _____ _____ Supports the ____ _____ Phalanges help form the ______ _____ | Cell body, stalk, phalangeal process, hair cells |
| b. Inner and Outer Pillar cells: form ______ ______ _____ and contribute to the _____ _____ i. Located between the ____ and _____ 1. Help maintain a strong structural attachment between the____ _____ and ____ | Tunnel of Corti, reticular lamina, IHC and OHC, reticular lamina, BM |
| 1. Membranous Semicircular canals(SSC) a. Similar in shape to the _____ semicircular canals b. Has ____ openings, all open into the ______ (located in the vestibule) c. Membranous ampullae correspond in their location to the osseous ampullae | osseous, 5, utricle |
| ______ contain the sensory organ for each semicircular canal, which comprises the _______ -______ | Crista Ampularis |
| Crista ampularis is made of: _____ ______ The ______ is the gelatinous portion of the crista ampullaris, the hair cells are embedded within the cupula | Supporting Membrane, Cupula |
| Mem. SSC 3. _____ hair cells a. The stereocilia of these hair cells deflect with movement of the fluid b. Kinocilium – the longest stereocilia of the hair cell | Sensory |
| SSC-Hair cell is _____ if stereocilia are bent ______ kinocilia & ______ if bent away | polarized, towards, hyperpolarized |
| The SSC contain ________ called crista ampullaris, which detect dynamic equilibrium (i.e., Responsible for sensing angular movements of the head) | mechanoreceptors |
| As your head rotates, the fluid in the SSC lags behind and will excite or inhibit the hair cells depending on the direction of the ______ | movement |
| Utricle and Saccule a. Housed within the______ vestibule b. Contain _____ – the sensory organ for the utricle and saccule c. Similar in composition to ______ ______ in the SSC | osseous, macula, crista ampularis |
| i. Macula is made of: 1. Supporting membrane (_______ cells) 2. The ______ membrane- the _______ portion overlaying the stereocilia of the hair cells a. This membrane differs from the SCC in that it contains _____ or ______ | Epithilial, otolithic, gelatinous, otoconia, otoliths |
| b. Otoconia or otoliths are ______ ______ crystals that provide ___ to the _____ membrane and make it responsive to gravity | calcium carbonate, mass, otolithic |
| 3. Sensory hair cells a. The ______ of these hair cells also deflect with movement of the surrounding fluid b. Also contains a______ | stereocilia, kinocilium |
| The maculae detect _____ ___ i.e., Senses ____ movements; _____ of head in the vertical and horizontal plane (movements of the body relative to the forces of gravity) The _____ (otoconia) make this sensory organ resp to gravity | static equilibrium, linear, acceleration, otoliths |
| Anatomy of the Auditory Nerve _____ and ______ fibers, the preponderance of fibers being ______ (this section is discussing the afferent fibers) | afferent, efferent, afferent |
| Afferent course of the AN The fibers of the AN orig. at the base of the ___ hair cells where the AN contacts the bottoms of the hair cells | cochlear |
| The AN fibers then courses through the ___ ____ – a bony structure of the osseous spiral lamina that has small openings through which the AN fibers pass | habenula perforate |
| Anatomy of Auditory Nerve: The nerve fibers from the different portions of the cochlea course together to form the ____ _____ cells held within ______ canals | Spiral Ganglion, Rosenthal's |
| d. Anatomy of Auditory Nerve: The ganglion cells collect to form the_______ of the _______ e. The nerve fibers in the modiolus course out of the cochlea and proceed into and through the ___ | trunk, modiolus, IAM |
| IAM- bony canal that houses: _____, _____ & _____nerves & portion of ______artery Carries these nerve bundles to the brainstem from the ______ | facial, auditory, vestibular, basilar, cochlea |
| IAM can be divided into four quadrants when viewed at the opening where the nerve fibers begin their ascent to the _____ | brainstem |
| IAM-A cross section: _____, ____ area contains _____ nerve _____ to the _____ nerve is the ____ portion of the ______ nerve | superior, anterior, facial, Inferior, facial, vestibular, 8th |
| IAM a cross section will reveal: _____ _____ and___ quad. houses the nerve fibers from the _____ and _____ Vestibular Portion of the _____ nerve | Posterior superior, inferior, superior, inferior, 8th |
| Innervation of the IHC & OHCs Innervation IHCS and OHCS-_____ innervation – __% of afferent fibers are connected to the ____ __% of afferent fibers are connected to the ____ Each IHC is connected to as many as ____ eighth nerve fibers This is termed a | Afferent, 95, IHCS, 5, OHCS, 10, many to one |
| Each OHC shares its innervation with ___ other OHCs (all being innervated by the same eighth nerve fiber) This is termed a “__ ___ ____” innervation | 10, One to Many |
| VIIIth nerve consists of two distinct types of fibers: ___ ___ fibers – large, _____ fibers Make up ____% of the VIII nerve The majority innervate the IHCs | Type 1, myelinated, 95 |
| VIIIth nerve consists of two distinct types of fibers: Type___ fibers – small, both myelinated and ______ fibers a. Innervate the OHCs (______) | unmyelinated, unmyelinated |
| e. Efferent innervation i. The efferent innervation of the OHCs is _____, reducing the afferent output caused by hair cell stimulation (To be discussed further in the Auditory Pathways outline) | inhibitory |
| Cochlear Phys:The __ is the first system to perform ___ of the incoming signal (sound) First level of auditory processing of the ___ signal It will extract or define the ___, ___ & temporal cues of that signal in order to transmit it accurat. to HAP | Cochlea, analysis, acoustic, frequency, intensity, temporal |
| Review Pathway of acoustical: Sound is a disturbance in air (acoustic) with __ and ___ These __ & ___ travel thru the outer ear, where it will cause the TM to move The ___ signal is altered to a ____ signal by the ___ _____ _____ of the middle ear | Compression, Rarefactions, C and R, acoustic, mechanical, Impedance Matching System |
| Movement is translated to the oval window (a ___ causes the stapes footplate to move ___and a rarefaction causes the stapes footplate to move ____) e. This movement is in direct relation to the frequency, intensity & timing of the original acoustic signa | compression, inward, outward |
| 3. The Traveling Wave theory by George von Bekesy a. The Traveling Wave is the movement of the ____ ____, the key player being the _____membrane, in relation to the input arriving at the oval window | cochlear partition, basilar |
| Traveling Wave Theory: Since the cochlear fluids are non-______, the vibration of the stapes results in the ______ of the non-compressible cochlear fluids along with a ______ _______(bulge) of the ____ window | compressible, displacement, compensatory displacement, round |
| TWT: The pressure wave that originates at the ___ window creates temporary pressure differences between the ____ ____ and scala ______ d. This pressure difference causes displacement of the ______ membrane | Oval, Scala Vestibuli, Scala Tympani, basilar |
| Comp. waves drive the BM ____ and rare waves drive it ____ Because the BM’s physical charact. and attachments, it has greater displacement _____ than radially (_____), though there is move across both planes The wave always travels from the ____ to ___ | downward, upward, longitudinally, transversely, base, apex |
| The cochlear operation of frequency analysis is dependent on the following mechanical properties of the BM: _____ ____, ____ ___, and ____ ____ | Graded Width, Graded Stiffness, Graded Mass |
| Graded width of BM The ___of the BM increases from ____ to ____ The width is greater at the __ than the base Graded stiffness The stiffness of the BM ___ from base to apex The apex is more ____, the base is more stiff | width, base, apex, apex, decreases, flaccid, |
| The traveling wave must represent the frequency and intensity of the stimulus coming in from the oval window, it does this by | Frequency – location of maximum displacement of the BM and-Intensity – The amount of deflection of the BM |
| 7. Tonotopic arrangement (frequency analysis) of the BM a. Different frequencies produce travelling waves that reach their ____ _____ at different places along the cochlear partition | maximum deflections |
| b. High-frequency stimuli cause _____ displacement of the BM in the___ region of cochlea c. Low-frequency sounds cause maximal displacement of the BM in the ____ region of the cochlea | maximal, basal, apical |
| Since the traveling wave always moves from base to apex, the __ end of the cochlea is stimulated by low-frequency sounds as well as by high, but the maximum displacement will be in the ___ end | basal, apical |
| The travelling wave gradually builds in __ as it moves away from the base of the cochlea, then after reaching its maximum it ___ rapidly i. This results in an “___” of activity that is asymmetric in shape (See Fig 10-3 of your text) | amplitude, decays, envelope |
| 8. Excitation of the Outer Hair Cells (OHCs) a. The cilia of the OHCs are embedded within the ___ ____ b. A ____ action is produced between the tectorial membrane and the cilia as the traveling wave moves along the ____ membrane | tectorial membrane, sheering, basilar |
| The ___ points for the ___ and ____ membranes are hinged in different points, and thus result in a ____ force that is greater than the ____ force would provide on its own | pivot, tectorial, basilar, shearing, vertical |
| Electromotility of OHCs Research has shown that OHCs can ___ and ___ upon stimulation This expansion and contraction works ___ with the ____ of the BM OHC contracts when BM moves ___ and expands when BM moves ___ | EXPAND, CONTRACT, SYNERGISTIC ALLY, DEFLECTION, UPWARD, DOWNWARD |
| Electromotility: Results in greater deflection of cilia at the point of -- 3. This action is termed the -- | maximum displacement, cochlear amplifier |
| Excit. of(IHCs) Depolari: (Excit. of hair cells) ___ ____ hold the stereoc together, causing the bundle to move in unison when a ____ force is applied | Cross Links, Shearing |
| ___ ____- course from the shaft of one stereocilium to the tip of the shorter stereocilium in the next shorter row | Tip LINKS |
| As the stereocilia bundle is deflected in the direction of the tallest row of stereocilia, tension increases in the ____ ____ ii. This will pull open the mechanically gated ___ channels located near the tip of the cilia | tip link, ion |
| A rarefaction wave, which displaces the __ upward will result in deflection of the stereocilia bundle toward the tallest ______ | BM, stereocilia |
| Deflection toward the tallest stereocilia (away from the _____) causes the _____ channels to open (depolarization) e. This allows __ to flow into the cell thru the channels, initiating depolarization of the cell | modiolus, transduction, K+ |
| The IHC releases the neurotransmitter (____), which diffuses across the ____ ____, activates receptors on the ____ membrane of afferent nerve fibers and depolarizes the fibers to generate an action potential | glutamate, synaptic cleft, postsynaptic membrane, |
| K+ flows into cell through channels, f. This leads to opening of CA2+ channels, which aid in repolarizing the cell & releasing neurotransmitters from the base of the ___ ____ | hair cells |
| 11. Hyperpolarization (_____ of hair cells) a. A ____ wave, which displaces the BM downward will stretch the ____ membrane and the cilia are pulled toward the ____ | Inhibition, Compression, tectorial, modiolus |
| Tip-links become slack, disallowing any ___ flow into the cell | ion, |
| This incr. the number of ____ channels that are closed and results in hyperpolarization of the hair cell iii. Hyperpolarization decreases the release of ___ from the hair cell and leads to a decre. freq. of firing of the auditory nerve fibers. | transduction, neurotransmitters |
| Neural Responses 1. Post-Stimulus Time ______ a. Used to look at data over time b. Neurons are all or ____ devices (fire in full or do not fire) | Histograms, None |
| When VIII nerve fiber responds to stimulation you get initial __ of activity, followed by decline back to a __ while stimulus is still being fired. | burst, plateau |
| Neural Responses: d. After stimulus is finished, the response of the fiber drops to below _____ (recovery period) and then rises back up to baseline | baseline |
| Nerve still needs to relay both __ and f__ information to the brain | intensity, frequency |
| 3. _____ organization of VIIIth nerve (Coding of frequency) a. Characteristic frequency of neuron i. The frequency to which a nerve responds __ ii. Responds to many frequency, but responds best to one frequency | best |
| 4. Coding of Intensity a. Firing rate hypothesis: As intensity of sound increases there is a corresponding increase in the average firing rate of the nerve b. Number of neurons hypothesis: More neurons fire to a louder ___ | sound |
| Two types of VIIIth nerve neurons: ____ ____ ____ (high threshold) and ____ ____ ____ (low threshold) | Low Spontaneous Rate, High Spontaneous Rate |
| Low spontaneous rate High threshold neurons require a higher level of __ to fire 2. They respond to the higher end of our auditory range of _ | stimulation, intensity |
| Low Spontaneous Rate Neurons-Have little or no random background firing ___ (that is why they are also termed low spontaneous rate neurons) | noise |
| ii. High spontaneous rate (low threshold) 1. Respond at very low ____ intensities and 2. Will display random firing even when no stimulus is present. | signal, |
| iii. So, more than likely the low threshold neurons are used for hearing sound at near-threshold or very ___ levels, whereas high threshold may pick up where the low threshold fibers stop, as the signal intensity increases | soft |
| Afferent Auditory Pathway The ____ nerve is the final structure of the auditory periphery a. ___ ___ neuron – i. From the base of the hair cells, ii. Exit the ___ ____ joining together to form the spiral ganglion | Auditory, First Order, habenula perforate, spiral ganglion, |
| Afferent Pathway: iii. Then course to the core of ___ and exit ____ iv. Enter ___ v. Synapse (terminate) in the ___ ____ with the second order neurons | modiolus, cochlea, IAM, cochlear nucleus |
| The second order neurons synapse with the __ ___ neurons and so on to the ____ level c. We will not discuss each of these “order neurons” in this course because their synapses are not entirely clear cut | third order, cortical |
| The most ____ fibers of the auditory nerve (fibers from the apical portion of the cochlea) follow a straight course and form the core of the nerve | apical |
| 3. The basal fibers (nerve fibers from the basal region of cochlea) are added in a ____ fashion to form the periphery of the nerve | twisted |
| 4. Because of anatomical architecture of the cochlear nerve, the ___ ____ fibers are the most exposed (on the periphery of the nerve) – more subject to trauma 5. The lower frequency nerve fibers are somewhat protected (core of the nerve) | high frequency |
| The Major Tracts of the ascending auditory pathway The Cochlear Nerve enters the ___ & is joined by the two divisions of the vestibular nerve to complete the VIIIth nerve Courses toward the brainstem, more specifically the ____ _____ | IAM, cochlear nucleus |
| The Cochlear Nucleus (CN) – the first structure of the central auditory nervous system (_____) | brainstem |
| At brainstem level, at least half of the neurons cross the median plane and ____ (cross over) to synapse at the ____ ____ ____ (i.e. ___ ______ ____)- the other portion stay ipsilateral (same side) | dessucate, superior Olivary nucleus, superior Olivary Complex |
| The neurons then travel ____from the superior olivary nucleus form a tract known as the ____ _____ e. The neurons then travel (some synapse, others travel uninterrupted) to the ____ _____ of the midbrain | superiorly, lateral lemniscus, inferior colliculis |
| At inferior colliculis of midbrain, Some nerve fibers will also decussate from one side to the other at this level | Yes. |
| The fibers then course through (or synapse at) the ____ ___ ___ – which is the ___ ____ of the auditory pathway The neurons will then course through and terminate in the ___ ____ (temporal lobe or “____ ____.) | medial geniculate nuclei, thalamic nucleus, Heschel’s” gyrus |
| Midbrain level: i. Because of the decussating nerve fibers, the cerebral auditory cortex receives input primarily from the ____ (opposite) ear via the ipsilateral (same side) ___ ____ ____ | contralateral, medial geniculate nuclei |
| 7. Tonotopic organization a. There is an orderly correspondence between the cochlea and the acoustic projection on the ____ _____ | cerebral cortex |
| Meaning that the tonotopic organization (frequency-related spatial distribution) of the cochlea and cochlear nerve is maintained through the ___ ____ ___ to the cortex | central auditory pathway |
| Efferent Auditory Pathway 1. The efferent auditory pathway begins at the auditory __ and courses ____ along a similar route as the ascending pathway until it finally reaches the ____ | cortex, inferiorly, cochlea |
| Efferent auditory pathway system has fewer fibers than the ____ system and is not as anatomically distinct | afferent |
| At many points the efferent system combines with the ___ system to form various feedback loops, making the descending pathway very complicated 3. The most studied portion of the efferent pathway is the _____ bundle | ascending, olivocochlear |
| a. The olivocochlear bundle (OCB) courses from the ___ ___ ___in the brain stem to the base of the hair cells | superior olivary complex |
| There are two types of neural connections in the efferent auditory pathway-______ Connections and _____ Connections | Ipsilateral, Contralateral |
| i. Ipsilateral connections 1. These fibers travel on the ___ ___ of the brainstem as the target cochlea. 2. The fibers in these connections synapse at the __ ____ ____and terminate at the ____ fibers of the inner hair cells | same side, superior Olivary nucleus, afferent |
| Contralateral connections These fibers travel on the _____ side of the brainstem from the target cochlea. The fibers in these connections synapse at the ___ ___ ___ and then cross the floor of the brainstem to join the ___ ____ in the ________ nerve. T | superior olivary nucleus, ipsilateral fibers, vestibulocochlear, outer hair cells. |
| Contra connection: About 4/5 of these neural fibers cross over and reach the cochlea from the contralateral ____ __ ___ | Superior Olivary Nucleus |
| Contra Connection: 4. The neural fibers travel through the ___ (in the opposite direction of the afferent fibers) entering the cochlea | IAM, |
| Contra Connection: 5. The function of the efferent system most likely has an _____ and / or regulatory effect on the output of the cochlea | inhibitory |
Created by:
sarchelj