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
Neuro II p33-50
Thomadaki Fall 2010
| Question | Answer |
|---|---|
| What is sound characterized by? | Frequency (pitch) & intensity (volume) |
| Frequency determines ______ and is measured in ____ | pitch, cycles/sec or Hz |
| Range of frequencies audible to humans | 20-20,000Hz or 20Hz to 20kHz |
| Frequency of ULTRASOUND? Heard by who? | >20kHz, animals |
| Frequency of INFRASOUND? heard by who? | <20Hz. Elephants and whales |
| What type of frequencies are implicated in car sickness? | Low frequency sounds |
| 3 functional divisions of the ear? | External, middle, inner era |
| External ear is composed of what two structures? | PINNA (auricle/tragus) - cartilaginous sound capturing convoluted funnel. EXTERNAL ACOUSTIC MEATUS (auditory canal). 2.5 cm tunnel that ends at ear drum |
| What is the middle ear filled with? | Air |
| Middle ear is composed of what 3 structures? | TYMPANIC MEMBRANE (9mm diam conical membrane) OSSICLES (malleus, incus, stapes) TENSOR TYMPANI & STAPEDIUS MUSCLES |
| What is the inner ear filled with? | fluid |
| What 2 structures are found in the inner ear? | COCHLEA (auditory system) - tube that is spiraling 2 1/2x around conical bony modiolus) VESTIBULE |
| What is the function of the middle ear? | Augment sound |
| does the convex/concave portion of tympanic membrane extend into the cavity of the middle ear? | convex |
| What are the ossicles held together by? | synovial membrane |
| What ossicle transfers tympanic membrane displacement to inner ear? | Stapes |
| Middle ear cavity connects to the nasopharynx via the ____, usually closed by a ______ and the _________ via the _____ | Eustachian tube (auditory tube), valve, mastoid air space (antrum), aditus |
| Mastoid air space is AKA? | Antrum |
| Tensor tympani attaches to what ossicle? | Malleus |
| Stapedius attaches to what ossicle? | Stapes |
| Function of the tensor tympani and stapedius? | Make ossicles more rigid in order to dampen v. loud sound |
| TT and stapedius decrease sound by what dB? | 10dB |
| What is the attenuation reflex? | Contracts, tensing up malleus and stapes, dampening loud sound. (doesn't protect from sudden loud sound). |
| What is the delay of the attenuation reflex? | 50-150msecs |
| The middle ear amends the sound so what percentage of waves reach the inner ear? Otherwise, what percent of waves would reach the inner ear? | 67%, 2% |
| The middle ear amplified pressure by ____x? What are the 2 ways it does this? | 22x; (1) surface area of oval window is 17x smaller than that of tympanic mem & (2) ossicles act as levers and increase force output on the oval window (the mvt on footplate of stapes is 1.3x the mvt of the arm of the malleus) |
| What are the two holes in the cochlea called? | oval and round window |
| Fluid movement is created when what happens? | oval window is displaced by stapes. |
| Most of the movements of fluid is absorbed by the fluid of the cochlea but any "unabsorbed" energy does what? | distorts the round window |
| What are the 3 fluid filled chambers of the cochlea? | Scala vestibuli, Scala media, Scala tympani |
| What membrane is located between scala vestibuli and scala media? | Reissner's membrane |
| What membrane is located between scala media and scala tympani? | Basilar membrane. |
| What chambers contain perilymph? | Scalas vestibuli & tympani |
| What two chambers connect? where? | Scalas vestibuli & tympani; Helicotrema |
| Ion concentration of perilymph? | Low K, high Na |
| What chamber contains endolymph? | Scala media (cochlear duct) |
| Ion concentration of endolymph? | High k, low Na |
| What structure is responsible for secreting K while absorbing Na against their concentration gradients? | Stria vascularis |
| Where is the organ of corti located? | On basilar membrane |
| Shape of basilar membrane | Narrow/stiff toward base; wide and floppy at apex |
| Base of basilar membrane codes for what type of frequency? | High frequency |
| Apex of basilar membrane codes for what type of frequency? | Low frequency |
| Arrangement of basilar membrane is called what? | Tonotopic map |
| What is the sensory receptor organ of hearing? | Organ of corti |
| What structures compose the organ of corti? | Inner and outer hair cells, rods of corti (pillar cells) & surrounding cells. |
| Organ of Corti is covered by what? | Tectorial membrane |
| The organ of corti is located where? | In scala medial which contains endolymph |
| Each hair cell has ___ (#?) _____ whose bending causes a _____ | 100 stereocilia; receptor potential |
| There are ______ inner hair cells arranged ______, located between the ____ & _____. | 3500; row; pillar cells & bony modiolus. |
| The stereocilia of the organ of corti extend where? | Into endolymph inferior to tectorial membrane |
| Hair cells synapse with? | Dendrites of bipolar spiral ganglion cells |
| Bipolar spiral ganglion cells are located where? And what do their axons form? | Modiolus; cochlear n. |
| What is the function of hair cells? | Convert mechanical energy that reaches the inner ear to a receptor potential |
| Upward movement of the basilar membrane has what effect? | Causes sterecilia to bend so that K channels on their tips open & depolarize the hair cells. --> causes Ca channels to open --> release of NTs (maybe glutamate) --> synpase between hair cells & dendrites of spiral ganglion |
| Downward movement of basilar membrane has what effect? | Causes hyperpolarization |
| Most of the spiral ganglion cells receive synapses from what type of hair cells? | Inner hair cells |
| Outer hair cells are implicated with what? | Sound amplification (by augmenting the movement of inner hair cells) in inner ear. |
| Ototoxic cells selectively destroy what? | Outer hair cells |
| What forms the cochlear n? | axons of spiral ganglion cells |
| Cochlear n travels where? and synapses with what? | Medulla; cochlear nuclei |
| What are the types of cochlear nuclei? and how many of each? | 2 ventral; 1 dorsal |
| What type of cells do ventral cochlear nuclei have? and what do they do? | Stellate cells; encode a variety of frequencies and bushy cells which fire at onset of sound and aid in localization of sound along horizontal axis |
| What type of cell does dorsal cochlear nucleus have? | fusiform cells; get excited/inhibited by a wide variety of frequencies and aid in sound localization along the vertical axis and tuberculoventral cells that respond with a delay and inhibit echo interference. |
| What is the function of tuberculoventral cells? | Delay and inhibit echo interference |
| Sound localization on vertical axis is controlled by what nucleus? | Ventral cochlear |
| Sound localization on horizontal axis is controlled by what nucleus? | Dorsal cochlear |
| Any injury above cochlear nucleus in auditory pathway leads to hearing loss on what side? | Hearing loss pronounced contralaterally |
| Cochlear nuclei synapse bilaterally with? | superior olivary nuclei |
| medial superior olivary nucleus is involved in localization of sound on ________ by _________ | horizontal axis; processing info about auditory time delay between 2 ears. |
| Interaural time delay is most striking in what frequencies? | low |
| Lateral superior olivary nucleus is involved in localization of sound by ____ | processing intensity difference between the 2 ears |
| Intensity interaural differences are most striking at what frequencies? | High |
| Fibers of superior olivary nucleus form the _______ | lateral lemniscus |
| Some fibers of superior olivary nucleus synapse with nuc of _____ but most synapse with _____ | lateral lemniscus; inferior colliculus |
| Inferior colliculus has 4 layered nucleus which gathers ____ &____ info. And a multi layered nucleus that has a ________ | auditory and somatosensory; tonotopic map |
| What shifts head toward stimulus | tectospinal tract |
| ______ receives info from inferior colliculus via the ______. Holding a _______. Fibers then form the ______ and end in _______ | medial geniculate nuc; inferior brachium; complete somatopic & tonotopic map; auditory radiation; primary auditory cortex |
| Where is the primary auditory cortex? it is _____ organized | Transverse temporal gyri of heschl (41, 42 of brodmann). tonotopically |
| Where is the second point of determining localization of sound source? | Transverse Temporal Gyri of Heschl |
| Conductive hearing loss results from insult to ______. Examples? | middle ear. Otitis media, otosclerosis |
| Sensorineural hearing loss results from injury to ______ there fore loss of ________ | inner ear; cochlear hair cells |
| if person talks very quietly what type of hearing loss might they have? | conductive |
| Weber's test - put tuning fork where? if sound lateralizes ipsilaterally then it's ______ deafness and contralaterally it's ________ deafness | vertex/nasion; conductive; sensorineural |
| Rinne's test - put tuning fork where? | mastoid process, when can't hear sound anymore place it near ear. |
| What type of hearing loss is tested in Rinne's test? | Conductive |
| Inner ear is composed of what 3 structures | Cochlea, Vestibule (utricle & saccule) and semicircular canals |
| The bony labyrinth contains ______, high in what ion? it is continuous with _____? | perilymph, Na, CSF |
| The membranous labyrinth contains ______, high in what ion? | Endolymph, K |
| Vestibular system helps with what 3 things? | Maintenance of posture, muscle tone, eye position with respect to head motion |
| The labyrinth is subdivided into ______ & _______ | static & kinetic labyrinth |
| Static labyrinth is composed of ______ & ______ which has what function? | sacuule & utricle; detects static orientation of head with respect to gravity. |
| What are the specialized hair cells in static labyrinth called? And they are embedded in ______ which contains _______ | macula utricle and macula sacculi; otolithic membrane; CaCO3 crystals |
| Kinetic labyrinth is composed of _______ which have what function? | semicircular canals; detect angular acceleration and deceleration. |
| Semicircular canals are _____ oriented so they can _____ | orthogonally; detect all possible directions of motion. |
| Where are the specialized hair cells in the kinetic labyrinth located? What are they called? and they are embedded in a _______ called _____ | Ampullae; crista ampullaris; gelatinous mass; cupula |
| Transduction of vestibular system - ____ ion influx causes hair cells to _____. When microvilli bend toward kinocilium the cells will ______; when microvilli move away, the cell will ______ | K, depolarize, hyperpolarize |
| Where does the vesitibular nerve enter the brain stem? | cerebellopontine angle lateral to facial n. |
| Where are vestibular nuclei located? | lateral aspect of floor of medullary and pontine part of 4th ventricle - underlying vestibular area |
| Axons from vestibular nuclei project to what 3 areas? | Flocculonodular lobe & fastigial nucleus of cerebellum; spinal cord (vestivulospinal tract); Brainstem nuclei of III, IV and VI bilaterally via MLF |
| Fibers from vestibular nuclei ascend to the ________ nuc --> _______ of cortex | posterior thalamic nuc; parietal association area |
| Internuclear ophthalmoplegia is caused by a lesion to what structure? What are the symptoms? What diseases do you see this? | MLF; Failure of CN III, IV, VI to carry out synchronous horizontal gaze; MS, or vascular d/e |
| Exams for Vestibular system? | BARANY CHAIR - spin around in chair, when stops should have nystagmus CALORIC TESTING: Cold Opposite Warm Same |
| Central lesion to vestibular system leads to what sx? | Nystagmus in various directions in absence of vertigo |
| Peripheral lesion to vestibular system leads to what sx? | Horizontal nystagmus only in presence of vertigo |
| Meniere's Disease. Onset? | idiopathic; dysequilibrium, nystagmus and vertigo coupled with progressive hearing loss and tinnitus. onset age 20-30 |
| Acoustic neuroma - type of tumor? location? May affect what nerves? | schwann cell tumor, usually around IAM or cerebellopontine angle; facial & trigeminal |
Created by:
mrw2013
Popular Chiropractic sets