Question | Answer |
Perilymph is low in _____ and high in ______ | K+, Na+ |
For high frequencies/pitch sounds, the greatest displacement is towards the ____ of the cochlea. | base |
Each turn of the cochlea is divided into 3 sections by membrane, these are called | 1) Scala vestibuli
2) Scala meida (cochlear duct)
3) Scala tympani |
Another name for the nasopharynx or auditory tube is the | Eustachian tube |
impedance mismatch between air and cochlear fluids is much like mismatch between _____ and _________. How much sound energy is lost? | air and water, 99.9% |
The cochlear nerve courses from the modiolus of the cochlea through the _____ ____ ____ | internal auditory meatus |
Endolymph is low in ___ and high in ______ | Na+, K+ |
Tops of cilia are filaments that are called | Tip links |
Many of the axons that cross the midline synapse at the SOC on the _______ side | contralateral |
pressure is much greater at tip of thumb tac because the _____ is over a larger area, same with TM and stapes | force |
Schrapnell's membrane, which doesn't have as many fibers and is less tense is called | Pars Flaccida |
The highly vascularized tissue that plays an extremely important role in function of cochlea. Inside it are iron pumps that maintain ion concentration of K+ and Na+ in Scala media. | Stria Vascularis |
sounds that occur in the ear canal without acoustic stimulation. These sounds originate in the cochlea and are present even when an external stimulus is not being presented to the ear. | Spontaneous OAEs |
malleus articulates w/incus>incus w/stapes, when ossicular chain vibrates>ossicles vibrate when oval window is pushed inward by ____ footplate, the _____ window bulges outward. Reissner's & Basilar's membrane are pushed down in scala ______ when pushed in | stapes, round, media |
When cilia bend towards outer wall of cochlea, causes K+ ion channels to ____ and K+ moves _____ hair cell, depolarizing hair cell. Charge moves from -40mV to zero. This results in release of ___ into cell which leads to discharge of neuron. | open, down into, NT |
When the stapes pushes down on Basilar membrane (cochlear partition) the compressional wave moving from the base > apex because of tension characteristics of Basilar membrane is a movement called the | traveling wave |
The cochlea is not simply a passive device receiving sound energy, rather it is an ____ system, which adds _____ energy to the transduction process | active, mechanical |
For high frequency sounds the maximum displacement is at the ____ of the basilar membrane. | beginning (base) |
For low frequencies/pitch sounds, the greatest displacement is towards the ___ of the cochlea. | apex |
This tube is slopped down and back and is more subject to collapse to infection in babies than adults because it is more horizontal and the milk accumulates in it. | Eustachian tube |
area with relatively high impedance | cochlear fluids |
acoustic energy is fed into the system, and the system returns... | acoustic energy |
This pathway consists of a series of nuclei or groups of ______ ______, and fiber tracts, or groups of _____. | cell bodies, axons |
The boost of energy given by the malleus and incus is called the | Lever Hypothesis |
The _____ of the malleus attaches to TM on outer side and makes it into a cone shape which has a tip that is called the ______. | manubrium, umbo (umbrella) |
Displacement is across whole system, but has places of higher displacement and our system can tune into this, this is called _________ _________ | hydromechanics filtering |
This structure separates scala vestibuli from scala media | Reissner's Membrane |
entire inner ear is filled with | fluid |
Presenting a low level tone in the ear causes an increase in the ____ of vibration of the BM at the point of its maximum displacement. So the peak of the traveling wave increases in size (also sharpness). | amplitude |
Which Pars is a part of the pressure regulating mechanism for ME? | Pars Flaccida |
Eustachian tube has two parts: | Osseous part and cartilaginous part |
In the membranous labyrinth the outside is ______ and the outside is _______. | perilymph, endolymph |
This energy from the cochlea is added by the outer hair cells changing their _____. That is, when an area of the basilar membrane vibrates, contraction and elongation of outer hair cells add a boost of _____ energy. | shapes, vibratory |
carries info from CNS to PNS, so away from brain | efferent |
pennate means that the muscle is | "feather" like |
Depolarization causes influx of ____, which causes opening of ___ channels. | Ca++, K+ |
A hole in the temporal bone that houses the ossicles is called the | ME Cavity |
The ear drum is also known as the | tympanic membrane |
What is the first bone in the chain of ossicles? | Malleus |
What muscle contracts when there is a "startle"? | tensor tympanic muscle |
A branch of the VII cranial facial nerve, which runs just behind manubrium of malleus is called the ______ ________. It carries taste from front of tongue (anterior 2/3 taste sensation) to brain and also has nerves that innervate the salivary glands. | Chora tympani |
Skin cells migrate from the tympanic membrane the the ___ ___ ___. | external auditory meatus |
However it does not move with an equal stiffness and the traveling wave is not equally ______ along membrane | displaced |
Cell bodies in the cochlear nucleus send some axons to the ipsilateral superior olivary complex, but most cross the midline in a fiber tract called the _____ _______. | trapezoid body |
what is the resonant frequency of the ear canal? | 2,000 Hz |
The SOC is known to be involved in the _______ of sound. | localization |
All of the axons _____ neurons in the cochlear nucleus that is located in the ______ ______ of the brainstem | synapse, medulla oblongata |
The SOC is the ___ major center on the pathway, and is the first level at which there is bilateral input of auditory ______. | 2nd, information |
nerves from cochlear nerve run through this ______ _______ _______ | osseous spiral lamina |
For low frequency sounds the maximum displacement is at the ___ of the basilar membrane | end (apex) |
Summary of Hair cell: 1)Cilia bend>K+ channels open, 2) K+ enters hair cell> causing it to ____. 3) This causes Ca++ channels to ___in membrane of cell and causes release of NT at ___ of hair cell. 4) Ca++ causes K+ to ___ in base of hair cells. 5) K+ ___ | depolarize, open, base, open, leaves the cell and cell then becomes repolarized (resting potential) |
Describe PEC < PME | Pressure is positive inside the ME cavity compared to the external air pressure. (Ex: plane flight going up) |
The articular facet joins with the | malleus |
In the Area ratio hypothesis, if you reduce area, pressure | increases |
Houses the utricle and saccule | Vestibule |
Bekesy discovered that the tension along Basilar membrane is held more ____ in base than apex. So it is more ____ in apex | stiffly, flaccid |
The Organ of Corti sits on top of Basilar membrane and has holes that are called ______ ________. These lead from spiral lamina into scala media | Habenula perfarata |
What if the Basilar membrane was equal in stiffness all the way along? | The whole membrane would move downward as a unit and go back to original position when stapes moves outward basilar membrane moves up. |
dendrite emerges through habenula perforata hole and becomes myelinated after the Organ of Corti, so this means that before it is not | myelinated |
This results in an increase in selective stimulation of ____ hair cells of that area. Hallowell Davis coined the term "_____ ______" to describe this mechanism. | inner, cochlear amplifier |
Above head of malleus and most incus is called _______ _______. | epitympanic recess (aka attic) |
Tip links are part of a mechanical system which opens ___ ______. | ion channels |
Nerve fibers course from the MGB along a pathway called the _________ _________ to the auditory _______. | auditory radiations, auditory cortex |
Other nuclei in the pathway are: | inferior colliculus and medial geniculate body (MGB) |
What is another name for the scala media? | cochlear partition/duct |
Name the three ossicles: | Malleus, Incus and Stapes |
Little further down cilia are filaments that tie cilia together and they are called | side links |
TM moves best when pressure of ME and OE is | equal |
area with relatively low impedance | air |
each has a widened portion called ampulla inside is sensory cells, which give us info on position of our heads (containing an organ of balance). | semi-circular canal(s) |
Middle ear cavity is also known as the | tympanum |
Name the three layers of the TM: | 1) Skin layer, 2) Middle fibrous layer, 3) Mucus membrane |
Outer hair cells sit in cup shape indentation of _____ cells. | deter |
When cilia go back to original position ___ channels close. | K+ |
Axons of the cochlear nerve enter the brainstem at the _______ ____ | cerebellopontine angle. |
When tensor palatini contracts it ______ tube and replenishes air in the ME cavity. | opens |
The mechanical energy is transduced into ________ energy by hair cells. | electrical |
What causes a traveling wave? ______ and _______ | compressions and rarefactions (takes 5 ms from base > apex) |
What forms the ionic barrier between endolymph and perilymph? | reticular lamina |
Describe PEC > PME | Pressure is negative inside the ME cavity because the TM is pushed inward by the external air pressure. (ex: sitting in class and not moving) |
an envelop plots the _______ displacement, each displacement plotted has a different envelope | maximum |
A hole that leads to another cavity which is the tympanic antrum is called the _______ _________. | tympanic aditus |
The filament (tip links) is believed to attach to a molecule on the cilium that acts like a ____ ____. | trap door. |
cochlear neuron is 1 axon and 1 dendrite, which is | bipolar=95% of cochlear neurons |
carries info towards CNS of brain | afferent |
cochlear nerve (cochlear branch of the VIII) and Vestibular nerve together create the ______ | cranial nerve VIII (Auditory nerve) |
Which one(s) are filled with endolymph? | Scala media |
In transduction the ear tranduces sound to mechanical energy in the form of vibrations of the _____ ________. | cochlear partition |
function of middle ear transfer sound _____ of air into fluids of inner ear. | energy |
The outer thickened area of the TM is called the ______, which fits into a groove in the bone, the tympanic ________. | annulus, tympanic sulcus. |
This structure separates scala media from scala tympani | Basilar membrane |
The cochlear nucleus is the "lowest" point in the ____ ______ of the brainstem. | auditory pathway |
The whole below the promontory is called the ______ _______. | round window |
What is the name of the bump on the medial wall? | Promontory |
low amplitude transient sounds that occur a few ms after a transient stimulus such as a click presented to the ear | Transient Evoked OAEs |
The middle part of the Cochlea is called the | modiolus (core of the cochlea) |
Inside hair cell charge of -____mV | -40mV |
the dotted line for a traveling wave that is plotted for the maximum displacement of a tone is called the | envelope |
process of fluid being moved in inner ear | cochlear partition |
When the stapedius muscle contracts it stiffens the ossicular chain therefore acoustic air doesn't travel through as readily, this is called the _____ _________. | acoustic reflex |
Inner and outer hair cells are bathed in | perilymph |
The ______ ________ contains tendon of stapedius muscle, which attaches to stapes. | pyramidal eminence. |
How does the cochlear partition move? | cochlear mechanics (hydromechanics b/c fluid system) |
K+ results in positive charge of +____mV above reticular lamina | +80mV |
The main part of the TM, that makes up the tense portion, is called | Pars Tensa |
What structure connects Scala vestibuli and Scala tympani? | Helicotrema |
Inner and outer hair cilia are bathed in | endolymph |
area that looks like a snail and where organ of corti is located. | Cochlea |
Which one(s) are filled with perilymph? | Scala vestibuli and scala tympani |
Inside this bump, ________ _______, is very porous bone and these are called mastoid air cells. If they get infected this might lead to a chronic disease. | tympanic antrum |
When basilar membrane vibrates, hair cell ________ are sheared or bent by the tectorial membrane. | stereocilia |
When the tallest row of cilia are bent in one direction, the "trap doors" in cilia in the next (shorter) row are ____, allowing K+ ions to flow through the cilia into the hair cell. The system is called "____ _____" mechanism. | opened, "gating spring" mechanism |
Above the Promontory is a hole that connects to the inner ear, which is called the ____ ______. | oval window (which leads to inner ear and fluid) |
which part is mainly opened by the tensor palatini (forms part of soft palate) and connects to sphenoid bone and hooks at pterygoid hamulus? | cartilaginous part |
The ______ ___ is located in the petrous portion of the temporal bone | Inner Ear |
Before entering the meatus it is joined by the two branches of the vestibular nerve; collectively the ____ and ____ nerves from the VIII cranial nerve | vestibular and cochlear |
This seperates ME Cavity from cranial cavity, a thin sheet of bone. If infected, get meningitis, life threatening disease. | tegmen tympani |
Ion channels are located in the ____ of hair cells | cilia |
The head of the malleus articulates with the | incus |
axon and part of dendrite have ____ sheath | myelin |
frequency is organized according to | place pr spacially |
what are the two middle ear muscles, which are both pennate muscles? | stapedius muscle, tensor tympani muscle |
a neural impulse/discharge which is a small change in voltage that travels along axon is known as an | action potential |
what is the resonant frequency of the corona? | 5,000 Hz |
What inner ear structure is 35 mm long, 2 1/2 turns in humans? | Cochlea |
Chorda tympani has _____ and _________ neurons | afferent and efferent |
The combined primary resonant frequency is | 2,500 Hz |
Discovered that many born deaf, system of replenishing potassium, _____ ______ is not working. | Stria vascularis |
Vibration of the TM results in sound being radiated into the ear canal this sound is called | otoacoustic emission |