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Thomadaki Neuro II

NYCC Thomadaki neuroscience final exam material SP10

sound waves are produced by periodic variations in _______________ air pressure (waves travel 343m/sec or 767 mi/hr)
what is the speed of sound 343m/sec
sound is characterized by its frequency and intensity
sound __________determines pitch. frequency
frequency determines ________. pitch
how is frequency measured? cycles per second or HERTZ
audible frequencies for humans are between _____________ HX 20-20,000HZ
what has a frequency of more than 20kHz and may be heard by dogs, cats, mice and dolphins? ultrasound
what has a frequency of less than 20Hz and may be heard by elephants and whales? Infrasound
What kind of low frequency sounds have been implicated in car sickness, infrasound or ultrasound? infrasound (low frequency)
low frequency sounds infrasound
high frequency sound ultrasound
humanly audible Hz 20-20kHz
frequency determines pitch
pitch is determined by frequency
how many functional divisions of the ear? 3
name the 3 functional divisions of the ear external, middle, inner (duh, you though that would be harder, didn't you?)
2 parts of the external ear pinna (auricle/tragus) and EAM (external acoustic meatus/auditory canal)
function of the pinna/auricle/tragus sound capture
function of the EAM tranfers sound to eardrum (2.5cm long)
what is in the middle ear air, tympanic membrane, 3 ossicles and the tensor tympani and stapedius muscles
name muscles of middle ear tensor tympani and stapedius muscles
name 3 ossicles of middle ear stapes, malleus, incus
nerve of middle ear chorda tympani of VII
inner ear is also called the labyrinth
the inner is filled with ________, unlike the middle ear which is filled with ______. fluid, air
the labyrinth is a fluid-filled ___________ membrane
parts of labyrinth cochlea and vestibule
another name for cochlea of inner ear auditory system
a tube spiraling 2.5 times around the conical bony modiolus cochlea
conical bony modiolus the spiral-shaped bone of the labrynthine cochlea
2 parts of inner ear/labyrinth cochlea and vestibule
how is the tympanic membrane positioned inside the middle ear, regarding its conical shape bowl-side (convex) inward
what ossicle is attached to the tympanic membrane malleus
how is sound transmitted by the middle ear? sound waves cause displacement of tympanic membrane (vibrate it) and this is transmitted to the ossicles
what holds the malleus, incus and stapes together? tiny synovial joints
how does the tympanic displacement get transferred to the inner ear? the stapes footplate pistons in and out onto the oval window, transferring the tympanic membrane displacement to the inner ear
connection between middle ear and nasopharyx eustachian tube (pharyotympanic tube)also called auditory tube
how is the Eustachian tube usually closed off? a valve and the mastoid air space (antrum) via the aditus
antrum mastoid air space
what is the function of tensor tympani and stapedius muscles? attached to tympanic membrane and stapedius, they dampen loud sounds (ergo, a prob. will present as hyperacousis)
hyperacousis the perception of sound as very loud due to the malfunction of the tensor tympani or stapedius muscles or their respective innervation
by how much do the inner ear muscles dampen sound? 10dB
Why doesn't the sound-dampening capability of tensor tympani and stapedius protect us from sudden loud sound? the attenuation reflex has a 50-150msec delay
sound has to travel from air-filled external ear to fluid-filled inner ear. What is the function of the middle ear? enhance the pressure so that the signal is not lost in translation/transition from air to fluid.
If the middle ear did not function to enhance the pressure required to transfer the signal, what would happen? only 2% of the sound energy would be transferred from the external to inner ear as compared to the 67% that actually is transferred.
By how many times does the middle ear amplify pressure? 22x
How does the middle ear amplify pressure by 22x? (2 ways) 1-surface of oval window is 17x smaller than the tympanic membrane surface, 2-the ossicles act as levers and increase the force output on the oval window
the movement on the footplate of the stapes is 1.3 times the movement of the ? arm of the malleus
2 ways middle ear amplifies pressure oval window is 17x smaller than tympanic membrane and ossicles act as levers to increase force output on oval window, essentially the fire hose becoming a garden hose (speed increases inverse to size of opening/tube)
a little oval window means a lot of sound forced through an opening that started out the size of the external acoustic meatus
name the two membrane-covered holes at the base of the cochlea facing the middle ear oval window and round window
what causes fluid movement inside the middle ear? displacement of the oval window by the stapes
what ossicle displaces the oval window, causing fluid movement? stapes
Where is movement of fluid (via displacement of oval window by stapes) absorbed in the middle ear? fluid in the cochlea
what causes distortion of the round window? unabsorbed energy by the cochlea from the oval window
3 fluid-filled chambers of the cochlea: scala vestibuli, scala media, scala tympani
name the 3 fluid-filled scala of the cochlea... vestibuli, media, tympani
Where is Reissner's membrane? between the s. vestibuli and s. media
sv/R/sm scala vestibuli/Reissner's/scala media
If Reissner's membrane is between the s.vestibuli and s.media, where is the BASILAR membrane? between s. media and s. tympani
the scala _________(containing perilymph), which lies superior to the cochlear duct and abuts the oval window vestibuli
the scala _______ (containing perilymph), which lies inferior to the scala media and terminates at the round window tympani
the scala _______(containing endolymph), which is the membranous cochlear duct containing the organ of Corti media
the scala media (containing __________), which is the membranous cochlear duct containing the organ of Corti endolymph
the scala vestibuli (containing _________), which lies superior to the cochlear duct and abuts the oval window perilymph
the scala tympani (containing __________), which lies inferior to the scala media and terminates at the round window perilymph
scala tympani + perilymph terminates at the _________window round
scala vestibuli + perilymph abuts the ________window oval
scala media + endolymph is the membranous cochlear duct and contains the _____________ organ of Corti
the _________ membrane, a main structural element that separates the scala media from the scala tympani and determines the mechanical wave propagation properties of the cochlear partition basilar
the basilar membrane, a main structural element that separates the scala media from the scala tympani and determines the _______ __________ propagation properties of the cochlear partition mechanical wave
the Organ of Corti, the ________ epithelium, a cellular layer on the basilar membrane, powered by the potential difference between the perilymph and the endolymph sensory
the ____________________, the sensory epithelium, a cellular layer on the basilar membrane, powered by the potential difference between the perilymph and the endolymph organ of Corti
the Organ of Corti, the sensory epithelium, a cellular layer on the basilar membrane, powered by the potential difference between the __________ and the __________. perilymph and the endolymph
describe PERIlymph molecularly lots of Na+ (therefore low in K)
describe endolymph molecularly high in K (ergo, low in Na)
which is higher in K+, endo- or perilymph? endo (K-endo media)
periNa perilymph is high in Na+ (like Purina)
the Scala vestibuli and tympani contain perilymph, which means these areas are high in ? Na (periNa)
The scala media is low in Na+ so it contains endolymph which is high in K (K-endo media)
K-endo media K endolymph {scala} media
hair cells, sensory cells in the Organ of Corti, topped with hair-like structures called ___________- stereocilia
what is the upper chamber of the cochlea which first receives vibration from the stapes via the oval windo? scala vestibuli's perilymph
Think of the cochlea as a long tube that's been divided into 3 chambers (like a peace sign) for it's entire length. The peace sign is on it's side, so what scala's perilymph gets the first vibrations and how? scala vestibula is connected to oval window, so when stapes knocks on oval window, the sound waves are tranferred into the s.vestibuli's perilymph first.
We know the scala vestibuli contains perilymph and is the first "slice" of the peace sign contacted via the oval window. What molecule is abundant in scala vestibuli? Na+ (because K-endo media)
what connects the s. vestibuli with the other perilymph-containing chamber, the s. tympani? helicotrema
where is the helicotrema that connects both the perilymph containing chambers of the cochlea? at the apex of the cochlea (this is the connection between s. vestibuli and s. tympani)
scala media is aptly called the cochlear duct (in older texts)
where is scala media/cochlear duct within the "peace sign" layout of the cochlea? it is the smallest chamber of the 3 scalae
what kind of perilymph does the s. media contain and what molecule is it rich in? endolymph, K (K-endo media)
The two scalae (fluid-filled chambers) communicate with each other through an opening at the top (apex) of the cochlea called the ___________, a common space that is the one part of the cochlea that lacks the lengthwise dividing membrane. helicotrema
The walls of the hollow cochlea are made of bone, with a thin, delicate lining of epithelial tissue. This coiled tube is divided through most of its length by a ________partition. Two fluid-filled spaces (scalae) are formed by this dividing membrane. membrane
The helicotrema (from Greek ἕλιξ meaning coil and τρη̂μα meaning hole) is the part of the cochlear labyrinth where the scala tympani and the scala vestibuli meet. It is the main component of the cochlear apex. The hair cells in this area best detect ? low frequency sounds
Tonotopy (from Greek tono- and topos = place) refers to the ? spatial arrangement of where sounds of different frequency are processed in the brain
tonotopy is how the ________ is arranged. cochlea
Tones close to each other in terms of frequency are represented in topologically neighbouring regions in the brain. Tonotopy in the auditory system begins at the cochlea, the small snail-like structure in the inner ear that sends information about sound to the brain
Different regions of the basilar membrane vibrate at different sinusoidal frequencies. The auditory nerves that transmit information from different regions of the basilar membrane therefore encode frequency tonotopically. This tonotopy is maintained in the human vestibule cochlea nerves cortex, that part of the brain that receives and interprets sound information
sounds of low pitch project into the anterolateral aspect of Heschl's gyrus, while sounds of high pitch project deeply into the lateral fissure (which houses Heschl's gyrus tonotopy
What is responsible for the layer of membrane in the s. media secreting ions of potassium (K) while absorbing sodium against the concentration gradients of both? stria vascularis
stria vascularis responsible for secreting K and absorbing Na in the s. media (the only one that has extra K to kick out!)
which chamber is the lower one in the cochlea? scala tympani
Where is the Organ of Corti located? on the basilar membrane
This motion of perilymph in turn vibrates the endolymph in the scala media, the perilymph in the scala tympani, the basilar membrane, and organ of Corti, thus causing movements of the hair bundles of the hair cells, acoustic sensor cells that convert? vibration into electrical potentials.
The hair cells in the organ of Corti are tuned to certain sound frequencies[1], being responsive to high frequencies near the oval window (______) and to low frequencies near the apex of the cochlea. base (oval window is base)
The spatial arrangement of sound reception (high freq. at base/oval window and low freq. at apex/hilicotrema)is referred to as tonotopy. tonotopy
The ______________ is the organ in the inner ear of mammals that contains auditory sensory cells, or "hair cells." organ of Corti (spiral organ)
basilar membrane is narrow at the base and therefore the base can only detect _______ frequencies high
the narrow end of the basilar membrane is ________ at the base, while the wide end is _______ at the apex. rigid (narrow) base, floppy (wide)apex
rigid narrow base high is to floppy wide apex low
rigid narrow base detects ________ frequencies high
floppy wide apex detects _________frequencies low
the narrow rigid base collecting high frequencies while the floppy wide apex collects high frequencies is reflected in the organization of the transverse temporal gyri of Heschel. What is the name for this continuity? tonotopic map
what sits on the basilar membrane of the cochlea? auditory sensory cells (hair cells) covered by the tectorial membrane
what membrane covers the auditory sensory cells (hair cells) as they sit upon the basilar membrane of the cochlea? tectorial membrane
there is a narrow ______ on a vase. base
the base of the basilar membrane codes? loud high frequency sounds
where is the Organ of Corti? on the basilar membrane
The Organ of Corti, sitting on the basilar membrane, is the sensory receptor organ of hearing. It has 5 structures: inner hair cells, outer hair cells, rods of Corti (pillars), supporting cells, tectorial membrane covering
In what chamber is the Organ of Corti? scala Media (k-endo media) with endolymph of K+
rods of Corti are also called pillars of Corti
What structure of what structure of the Organ of Corti bends to produce a receptor potential? stereocilia of a hair cell of the Organ of Corti
how many stereocilia per Organ of Corti hair cell? 100
How many inner hair cells? 3500
How many outer hair cells? 12,000
approx. ratio of inner hair cells to outer hair cells 1.5:4
where are the 3500 inner hair cells of the Organ of Corti in a row located between the pillar (rod) cells of Corti and the bony modiolus
what is a bony modiolus? The walls of the hollow cochlea are made of bone, with a thin, delicate lining of epithelial tissue
The hair cells are arranged in four rows in the organ of Corti along the entire length of the cochlear coil. ________ rows consist of outer hair cells (OHCs) and _____ row consists of inner hair cells (IHCs three, one
The _______ hair cells provide the main neural output of the cochlea. inner
which hair cells provide the main neural output of the cochlea? inner
The outer hair cells, instead, mainly receive ______________________________, which influences their motility as part of the cochlea’s mechanical pre-amplifier neural input from the brain
which hair cell receives neural INput from the brain outer
What nucleus of the brain is the primary output to the outer hair cells of the cochlea? olivary body/nucleus via medial olivo-cochlear bundle
Inner Hair Cells (IHC) number 3500 between the pillars and modiolus. Their stereocilia extend into the _________ inferior to the tectorial membrane. endolymph
What structure's structures (hahaha I know) extend into the endolymph below the tectorial membrane? the stereocilia of IHC
do inner hair cells INput or OUTput? OUTput
In goes Out and Out goes In (explain this in regards to hair cells) Inner hair cells = Output, Outer hair cells = Input
There are 12,000 OHC (Outer Hair Cells) receiving neural input from the olivary nucleus. Where are these little soldiers located? distal to the pillar/rod cells of Corti
How far does the stereocilia of an OHC extend into the endolymph? all the way to the tectorial membrane!
basilar membrane vibrations induce recpetor potential in the HC's of the corresponding cochlea region. Of the two rows of HC's, the inner row cells act as true ____________________. true auditory receptors
Hair cells synapse with dendrites of ________ spiral ganglion cells located in the modiolus and whose axons form the Cochlear nerve (1/2 of VIII). bipolar
Hair cells synapse with dendrites of bipolar _______ ganglion cells located in the modiolus and whose axons form the Cochlear nerve (1/2 of VIII). spiral
Hair cells synapse with dendrites of bipolar spiral ganglion cells located in the _________ and whose axons form the Cochlear nerve (1/2 of VIII). modiolus
Hair cells synapse with dendrites of bipolar spiral ganglion cells located in the modiolus and whose _______ form the Cochlear nerve (1/2 of VIII). axons
Hair cells synapse with dendrites of bipolar spiral ganglion cells located in the modiolus and whose axons form the ______________(1/2 of VIII). cochlear nerve
What converts the mechanical energy that reaches the inner ear to a receptor potential? Hair cells
Hair cells convert the mechanical energy that reaches the inner ear to a _______________. receptor potential
Hair cells + mechanical energy = receptor potential
What causes all the structures of the Organ of Corti to move either up or down, causing the stereocilia to bend sideways in one direction or the other? When the basilar membrane is affected by the scala's fluid movement
Downward movement of the basilar membrane causes hyperpolarization. (shut down)
hyperpolarization of the hair cells is caused by what movement? downward
what happens during upward movement of the basilar membrane? Stereocilia bend so the K channels on their tips open and depolarize the hair cells.
upward basilar movement means depolarization due to stereocilia K channels opening
After upward basilar membrane causes stereocilia to open K channels and depolarize hair cell, what happens? Calcium! channels open and neurotransmitters (maybe glu)are released. A synapse then occurs between the Hair cells and the dendrites of the spiral ganglion
There are approximately _________ spiral ganglion cells, most of which receive synapses from the inner hair cells. 30,000
From where do the 30,000 spiral ganglion cells receive their synapses? Inner Hair Cells (remember, inner is output)
Which cells are responsible for pathological hyperacousis? Outer hair cells, because they increase the movement of inner hair cells which in turn output a crapload of synapses to the spiral ganglion and BOOM! hyperacousis!)
what kind of ganglia do hair cells synapse upon to conduct receptor potential? spiral
Spiral ganglia = hair cells
The axons of the ________ ganglion cells form the cochlear nerve, which follows the tonotopic organization of the basilar membrane. spiral
the Axons of the spiral ganglion cells form the _________ nerve. cochlear nerve (1/2 VIII)
The Cochlear nerve/axons of spiral ganglion follow tonotopic organization of the basilar membrane, which means that each fiber is most responsive at a specific ___________. frequency.
The tonotopic org of cochlear nerve/axons of spiral ganglion means that nerves coming out of the apex basilar membrane will, like the hair cells present in the apex, respond to ___________ frequency. low (and the spiral ganglion/cells of the cochlear nerve coming out of BASE hair cells will respond to HIG frequencies because it is "base shaped like a vase is high falutin'!"
the spiral ganglion/cochlear nerves are going to travel to the _________ and synapse with the cochlear nuclei. medulla
There are two _________ and one ________ cochlear nuclei. Each has 2 types of cells. 2ventral, 1dorsal
Ventral cochlear nuclei have ______ cells and _______ cells. stellate & bushy
There are ____ ventral cochlear nuclei and they have __________ cells and _________ cells. 2, stellate, bushy
2 thorny bushes in the front of the house. 2 ventral cochlear nuclei with stellate and bushy cells.
Stellate cells of the 2 ventral cochlear nuclei encode a variety of ___________. grequencies
Bushy cells of the 2 ventral cochlear nuclei fire at the onset of sound and AID in the ____________ of sound along a HORIZONTAL AXIS. LOCALIZATION
bushy ventral cochlear nuclei cells aid in the localization of sound on the horizontal axis
stellates are the transponders and bushies are the guns and sighting. stellates encode frequencies and bushies fire at onset of sound and localize the sound in the horizontal axis.
THe dorsal cochlear nucleus has ________ cells and _________________ cells. fusiform, tuberculoventral
fusiform bundled, like muscle cells
The dorsal cochlear nucleus has _________ cells that get excited or inhibited by a wide variety of frequencies and AID in sound localization along the vertical axis. The dorsal nucleus also has ________________ cells. fusiform, tuberculoventricular
fusiform = vertical axis location for dorsal cochlear nucleus
_________________ cells of the dorsal cochlear nucleus respond with a delay and inhibit echo interference. Tuberculoventricular
which cells localize sound in the horizontal axis? bushy cells of the ventral cochlear nuclei
which cells localize sound in the vertical axis? fusiform cells in the dorsal cochlear nucleus.
which cells respond with a delay and inhibit ECHO interference? tuberculoventricular cells in dorsal cochlear nucleus.
which cells transpond/encode a lot of frequencies? stellates in the ventral cochlear nuclei
stellate, bushy, fusiform, tuberculoventricular cells of the ventral cochlear nuclei (2) and dorsal cochlear nucleus (2) respectively.
The cochlear nuclei synapse bilaterally with the SON of an Inferior Colliculus!
SON Superior Olivary nucleus
The cells of the cochlear nuclei will bilaterally synapse with the SON (Superior Olivary Nucleus)
SON, the docking station for cochlear nuclei, achieves localization of the sound source along the ___________ axis by processing the auditory time delay between the two ears. In other words, what does the SON do? decides if the sound came from the left or right side.
When is the delay between the two ears (interaural time delay) detected by the SON most apparent? low frequencies. (ie, you can tell which side the sound came from/horizontal axis detection if the frequency/pitch is LOW
It is difficult to distinguish _______ frequencies on the horizontal axis based on the interaural time delay. high
The SON not only detects which side the sound came from (horizontal axis) but processes the intensity difference between the two ears. Intensity interaural differences are most striking at ______frequencies. high
Intensity differences are most striking at high frequencies because there is a higher rate of firing of nerve impulses from the associated auditory fibers, then to the cochlear nuclei, then to the SON. Auditory centers dtermine loudness by comparing firing of one auditory n. to one that is resting.
SON is intraural time differences (horizontal axis/left or right side sound source) via ______ frequencies and intensity difference via _____ frequencies. low (left/right), high (intense)
low (left/right), high (intense) is SON
Fibers from the SON form the _______________ lateral lemniscus.
Some SON fibers are going to synapse with the lateral lemniscus nucleus, but most are going to synapse with the Inferior colliculus
The inferior colliculus, target of most of the SON fibers, has a 4-layered dorsal nucleus that gathers ___________&_________ info, and a multilayered central nucleus that has a complete ______________________. auditory & somatosensory, tonotopic map
From the inferior colliculus, sound fibers travel along the ____________________ to the Medial geniculate body. inferior brachium
Medial geniculate body via inferior brachium from the inferior colliculus. The MGB holds a complete __________ map. tonotopic
From MGB, where do fibers go? Auditory radiation to end in PAC
PAC primary auditory cortex
Broadmann's areas 41 and 42 Transverse temporal gyri of Heschl
Broadmann's areas 41 and 42 located near the superior temporal gyrus Transverse temporal gyri of Heschl
Is the transverse temporal gyri of Heschel tonotopically organized? yes
What is the second point of determining sound localization? Transverse temporal gyri of Heschl
What are the two structures that determine sound localization SON and TTGHeschl
It has columns that are responsive to every audible frequency and interaural relationship. TTGHeschl
A lesion to the SON or the TTGHeschl means we cannot localize the source of the sound
Conductive hearing loss results from an insult to the _______ ear. middle
_____________hearing loss results from an insult to the middle ear. Conductive
What may result in formation of scar tissue that hinders the movement of the tympanic membrane or the ossicles? Otitis media
What disease may result in ossification of the attachment between the ossicles? Otosclerosis (a disease with no known cause)
What two kinds of Conductive hearing loss? Otitis media and Otosclerosis
What kind of hearing loss results from loss of cochlear hair cells? Sensorineural hearing loss
Sensorineural hearing loss results from the loss of cochlear hair cells
Place a tuning fork on vertex or nasion (along the midline of the skull). The sound lateralizes to the ear with the conductive deafness OR away from the ear with sensorineural deafness. Weber's test
During Weber's test, the sound lateralizes to the ear with ______________. Conductive hearing loss (Conduct means "to" so the sound is "conducted to" the side of hearing loss during Weber's test)
During Weber's test, the sound lateralizes AWAY from the ear with Sensorineural hearing loss AWAY
Rinne my bell Rinne's test is a tuning fork up against the mastoid, and when patient can no longer hear it, place fork next to ear. Should hear it. If cannot, then conductive loss expected.
What kind of loss is expected with a positive Rinne's test? conductive
3 parts of labyrinth cochlea, vestibule (utricle and saccule), semicircular canals
The vestibule 2 parts utricle and saccule
The bony labyrinth contains ____________ which is rich in _____. perilymph, Na+
What kind of fluid does the bony labyrinth contain and what other part of the ear contains this fluid, too? perilymph (Na+) is contained in the bony labyrinth of the inner ear and the sacula vestibuli and sacula tympani of the middle ear.
If the bony labyrinth contains perilymph (Na+), what does the membranous labyrinth contain? endolymph (K)
Why does the membranous labyrinth containing endolymph/K communicate with the endolymphatic sac? the sac continually absorbs the continually produced endolymph
posture, muscle tone, eye position with respect to head motion are all functions of the ______________ system. vestibular
2 divisions of Vestibular system: Static & Kinetic
composed of utricle and saccule Static labyrinth
detects static orientation of the head with respect to gravity, includes utricle and saccule Static labyrinth
Specialized cells in Static labyrinth are called ________ utricle and _______ saccule. macula
Static labyrinth has ________ cells. Macula
macular utricle and macula saccule are in the ____________ labyrinth of the vestibular system. Static
The hair cells in the maculae of the Static labyrinth are embedded in a gelatinous mass called the ___________, which contains CaCO3 crystals. otolithic
What kind of crystal/mineral does the otolithic membrane of the Static labyrinth contain? CaCO3 (calcium carbonate)
Static labryinth association words vestibular, saccule, utricle, macula, otolithic membrane, calcium carbonate
Kinetic labyrinth implies movement!
Labyrinth composed of semicircular canals which detect angular acceleration and deceleration. Kinetic
The semicircular canals of the Kinetic labyrinth are ______________-oriented so they can detect motion in all possible directions. orthogonally (right angles to one another)
The ends of each the semicircular canals of Kinetic labyrinth ampullae (each ends in an enlarged bell shape)
word associate Kinetic labyrinth vestibular, ampullae, crista ampullae, cupula, semicircular canals, orthogonal
Name of the specialized hair cells in the semicircular canal ampullae? crista ampullaris
The Static maculae are embedded in a gelatinous mass called the otolithic membrane (CaCO3). What are the special hair cells of the Kinetic labyrinth embedded in? cupula
The whole thing is called the ampullae, and within it the special kinetic hair cells are called crista ampullae. They are contained in an upside down cup called the _________. cupula
Transduction in the vestibular sys is the same as in the cochlear system because the two are continous. What, exactly, IS continuous between them? endolymph (K)
What causes hair cell DEpolarization? K (potassium)
Potassium causes hair cell DEpolarization
Hair cells (crista ampullae and maculae, both) have microvilli on one end with a longer ____________ on the opposite end. Kinocilium
IF the microvilli bend toward the kinocilium and pay homage, what happens? DEpolarization
If the microvilli ignore the kinocilium and lean away, what happens? hyperpolarization
After DEpolarization, the hair cells have receptors that synapse with dendrites of __________cells called vestibular ganglia or ___________ ganglia. bipolar, Scarpa's
Scarpa's ganglia synapsing with the static and kinetic labyrinth hair cells have the axons which form the ____________nerve. vestibular
associate Scarpa's bipolar vestibular ganglion whose axons form the vestibular nerve and whose dendrites synapse with the hair cell receptors of either maculae or crista ampullaris
Where to after vestibular axons from Scarpa's ganglion? enters brainstem at the cerebellopontine angle lateral to facial nerve
Where are the vestibular nuclei? under the vestibular area in the 4th ventricle space/"lateral aspect of the floor of the medullary and pontine part of fourth ventricle, underlying the vestibular area"
4 projection areas of Vestibular nuclei: floccunodular lobe and fastigial nucleus of cerebellum (go together always for proprioception), spinal cord vestibulospinal tract, and the brainstem nuclei of III, IV, VI bilaterally via the MLF, and finally the VPN of thalamus so it gets to the parietal.
What is implied by vestibular nuclear projections to Oculomotor, Trochlear and Abducens nerves? Your proprioreceptive balance much affects your eye movement, thankfully!
4 vestibular nerve nuclei projections flocculonodular lobe/fastigial nucleus of cerebellum, vestibulospinal tract of spinal cord, brainstem nuclei of III,IV, VI via the MLF (eye movement), and finally to VPN of thalamus so to parietal assoc. areas of cortex
How does vestibular info get to the parietal association areas of the cortex? via the vestibular nuclei projection to the VPN of thalamus
internuclear ophthalmoplegia III,IV and VI fail! to carrout synchronous horizontal gaze due to MLF lesion
Internuclear ophthalmoplegia is seen in what kind of patients? MS or vascular disease
Is internuclear ophthalmoplegia specific to vestibular disease? NO!
lesion to MLF internuclear ophthalmoplegia
rotates 10x in 20 sec., patient flexes forward 30degrees, rotation stops abruptly. An intact Vestibular system will produce? Barany chair: nystagmus! (named for fast component) opposite rotation.
Barany chair intact system produces nystagmus during opposite rotation
warm or cold water in external acoustic meatus Caloric testing
Warm water produces nystagmus in _________ side in an intact vestibular system. same (WSI is Warm Same Intact)
Cold water produces nystagmus in the ____________ side of an intact vestibular system. opposite is COW Cold Opposite Water
vestibulo-ocular reflex? Grab head of patient gently/firmly – if you shift their head, they are still looking at you. If vestibular sys not working, then eyes go with head and cannot shift back.
symptoms of vestibular lesion (3) vertigo, nystagmus, dysequilbrium
symptoms of __________ lesion may produce nystagmus in various directions in the absence of vertigo. central
Which system, central or peripheral, will produce a horizontal nystagmus only in the presence of vertigo? peripheral
nystagmus without vertigo central
nystagmus only when there IS vertigo peripheral
vestibular symptoms such as equilibrium loss, nystagmus, vertigo accompany progressive loss of hearing and tinnitus. Age of onset 20-30 yrs. Meniere's disease
Meniere's symptoms (5) vertigo, nystagmus, dysequalibrium, progressive hearing loss, tinnitus
Is Meniere's central or peripheral? why? peripheral because nystagmus in presence of vertigo
Acoustic neuroma is also called Schwannoma
tumor of the vestibular nerve; slow growing and relatively benign Schwannoma/acoustic neuroma
Where is an acoustic neuroma/Schwannoma typically found? internal acoustic meatus or cerebellopontine angle
What other nerves may an acoustic neuroma/Schwannoma affect besides CN VIII? V and VII
Schwannoma may affect cranial nerves? V, VII, and VIII because of the exit locations of the nerves in relation to one another
We can detect the smell of several hundred thousand odors. What percentage are noxious and what percentage are pleasant? 80% noxious, 20% pleasant
Around what structure is the olfactory epithelium located? cribriform plate of ethmoid bone
3 main types of olfactory cells 1-basal, 2-receptor, 3-support
There are 3 Olfactory cell brothers (BRS.): Basal, Receptor, Support
stem cells that will become new olfactory cells Basal (BRS.)
bipolar cells whose dendrites bind to odorants and whose unmyelinated axons form the olfactory nerve Receptor (BRS.)
which olfactory brother cell's axons form the olfactory nerve CN I? Receptor (BRS.)
What is the third type of olfactory cell brother besides Basal and Receptor? Supporting (BRS.)
What kind of epithelium lines the respiratory tract? goblet cells and mucus-secreting gland cells
Odorant molecules bind to _______ on olfactory receptor cells. cilia
Odorant molecules bind to cilia on olfactory __________cells. Receptor (BRS.)
which cell type is the stem cell that becomes new olfactory receptor cells? Basal (BRS.) becomes Receptor and they are Supported by other cells. They are a band of BRS.
precursor to Olfactory neuron Basal cell (BRS.)
precursor to Olfactory neuron Basal
Cilia of _________________cells are embedded in the mucus layer, right below the olfactory epithelium. Odorants get stuck in the mucus and bind to the cilia on the dendrites of these cells. olfactory receptor
Describe an olfactory receptor cell Cilia hanging off end of dendrite like a broom on a handle (handle being dendrite), top of broomstick has olfactory receptor cell body, and off cell body is one of the axons that will form the Olfactory CN I, itself.
Where does the receptor potential happen on an olfactory receptor cell? At the cilia-dendrite junction when the odorants have bonded to the cilia
Where do action potentials take place on an olfactory cell? at the olfactory cell body (summation)
Where is the conduction zone of the action potential (50mV) on an Olfactory cell? In the axon of the Olfactory nerve, CN I, coming off the cell body of the olfactory cell
Vestibular sys stands you up to pay attention. It is always through the _______ ear. Eyes always meet the horizon. inner
_________labryinth detects movement at beginning and at end of movement Static
Ampulae is where the ___________ cells live detector
Weber’s is tuning fork. Id side with problem first – conclusion is : ipsilateral __________ loss on right or contralateral ____________ loss on the left sensorineural, conductive is contralateral loss
conductive is __________ loss contralateral
The sound lateralizes to the side with ____________ hearing loss so you hear it louder on that side. conductive
Discrepancy on one side but normal on other is ____________ hearing loss conductive
_________ test actually tells you which kind of hearing loss Weber's (discerns sensorineural from conductive hearing loss)
Usually conductive is lost __________ because due to infection unilaterally
injury of the middle ear, via tympanic membrane, ossicles, infections, autosclerosis, resembles putting finger in ear (plugging sound) conductive
hearing loss – destroy hair cells. Nerve getting no input. Cannot detect vibration via air or bone sensorineural
Conductive or Sensorineural hearing loss is ______________ irreversible
The hair cells in the maculae are embedded in a gelatinous mass, the otolithic membrane which contains ________ crystals CaCO3
The hair cells in the __________ are embedded in a gelatinous mass, the otolithic membrane which contains CaCO3 crystals maculae
Endolymph has potassium. K+ comes in, polarizes cell, causes____ to be released. Ca+
Kinocilium- longer on one end, when microvilli bend to the long one the cell _______________. Moves to other side and the cell hyperpolarizes DEpolarizes
__________POTASSIUM channels with Ca+ synapse with dendrites of bipolar cells called Scarpas Ganglion (Vestibular Ganglion) mechanical
Cold water produces nystagmus to the _________ side of irrigation opposite
theory is fluid tension is too high, causing abberrant movement Meniere's disease
Reproduction which produces NYSTAGMUS only is _____.Nystagmus with VERTIGO is _____. CNS, PNS
Olfactory nerves go through the cribriform plate to synapse with (2)? in the olfactory bulb. mitral and tufted cells
mitral and tufted cells are located in the olfactory bulb
what are mitral and tufted cells what olfactory nerves synapse on in the olfactory bulb
Olfactory bulb fibers are _________-order neurons. 2nd
Olfactory bulb fibers proceed in the olfactory tract which then divides into? medial and lateral olfactory striae
medial olfactory stria goes to opposite bulb through anterior commissure
connection between medial olfactory striae anterior commissure
lateral olfactory stria project to Primary Olfactory Cortex (POC)
POC primary olfactory cortex contains (2) entorhinal and piriform cortex
where is the POC (entorhinal and piriform cortices) located? anterior Parahippocampal gyrus surrounding amygdala
The olfactory system is cosidered to be a subsystem of the _________system. limbic
Olfactory receptor cells have what structure on their tops that synapse with ehe 2nd order olfactory neuron that makes up the olfactory tract? glomerulus
relays information to the orbitofrontal olfactory cortex and dorsomedial thalamic nucleus piriform cortex
the ________cortex relays information to the olfactory association cortex and dorsomedial thalamic nucleus. piriform
the only sense that reaches the brain without first going through the thalamus olfaction
3 olfactory cortical regions orbito-frontal cortex/olfactory association area, entorhinal cortex, piriform cortex
gustation taste
embedded between epithelial cells on surface of tongue are gustatory sensory/receptor cells
3 gustatory nerves of tongue VII Facial as Chorda Tympani for anterior 2/3, IX Glossopharyngeal for posterior 1/3, and X Vagus for epiglottis
What kind of taste cells send their central axons from their ganglion (VII, IX, and X) to the solitary nucleus? pseudounipolar
Ganglion of VII for taste geniculate ganglion for chorda tympani (anterior 2/3 of tongue)
Ganglion of IX for taste inferior ganglion (posterior 1/3 of tongue)
Ganglion X for taste inferior-nodose-ganglion (for epiglottis)
From cranial nerve ganglion VII: __________, IX:____________ and X:______________, central axons from the pseudounipolar cells are sent to synapse in the SOLITARY NUCLEUS. VII: geniculate for chorda tympani, IX: inferior ganglion, X: inferior-nodose-ganglion
Where are the axons from ganglia of Facial, Glossopharyngeal, and Vagus headed with taste information? Solitary Nucleus (7.9.10)
The secondary afferents from the __________ tract ascend through the brainstem with taste info and synapse with the ventral posteromedial thalamus (VPN) solitary tract
Nerves 7.9.10 to solitary nucleus to solitary tract to? VPN of thalamus
From VPN of thalamus, where do the 3rd order neurons head? through posterior limb of internal capsule to the primary gustatory cortex
The primary Gustatory cortex has 3 locations for it's final 3rd order neuron from the VPN: 1-inferior postcentral gyrus, 2-OPERCULUM, 3-superior insula
On the quiz, what part of the primary gustatory cortex was identified? Operculum
What are the 3 parts of the primary gustatory cortex? inf. postcentral gyrus, Operculum, superior insula
the taste-sensitive structures on the tongue papillae
largest and most posterior papillae on tongue circumvallate papillae
Elongated papillae on tongue Foliate papillae
Relatively large papillae towards back of tongue that are much smaller on sides and tip Fungiform
A taste bud is a cluster of taste cells (receptor cells), gustatory afferent axons and synapses with taste cells, and basal cells
taste/receptor cells, gustatory afferent axons and synapses with taste cells, and basal cells all make up a taste bud
Microvilli at the apical end of taste cells extend into the taste pore
the site where chemicals dissolved in saliva can directly interact with taste cells taste pore
Taste I area somatosensory cortex
Taste II area insula
Name the Taste I and II areas Somatosensory cortex (I)and Insula (II)
At the solitary nucleus level (4th ventricle), what happens to taste afferents from tongue and epiglottis (VII, IX, X)? Cross Great Sensory Decussation to VPN of contralateral thalamus, synapse, then 3rd order goes to gustatory cortex (inferior postcentral gyrus is the somatosensory cortex taste area I, Operculum, and superior Insula taste area II)
salty primary ion entering? direct or 2nd messenger? Na+ direct to depolarize, Ca+ in to release NT
Sour primary ion entering? direct or 2nd messenger? H+ or H+ block potassium channel direct to depolarize, Ca+ in to release NT
Sweet primary ion entering? direct or 2nd messenger? tastants bind directly to G-protein linked receptors, cAMP block potassium, depolarize, Ca+ in to release NT
Bitter primary ion entering? direct or 2nd messenger? Can either block potassium (bitter 1) or bind to G-protein linked receptor (bitter 2) to IP3, release Ca+ from internal storage site. PIP.
Umami/savory primary ion entering? direct or 2nd messenger? Na+ but is a receptor for amino acids GLUTAMATE or ARGININE to depolarize, then Ca+ in to release NT
2nd messengers are bittersweet
the visual field of each eye is separated into 4 quadrants (upper, lower, right, left)
the quadrants of visual field are also called (right and left) nasal and temporal
The _________receives the visual field projection RETINA
Receives the visual field projection retina
In the retina, the the visual field projection image is crossed and inverted
The Temporal 1/2 of visual field projects in the nasal 1/2 of the retina
Think of the visual field as a rectangle, divided in two with the medial half called the nasal visual field and the lateral half called the temporal visual field. Now think of the eyeball as divided in half, with the medial half called the nasal retina and the lateral half called the temporal retina.
The temporal visual field projects into the ____________ retina. nasal
The nasal visual field projects into the ____________ retina. temporal
Think of the visual field as a rectangle, divided into upper and lower halves. The upper half projects to the Temporal lobe. The lower half projects to the Parietal lobe (just the opposite of what you'd expect) The upper half of the visual field (temporal lobe) projects to lower retina. The lower half of visual field (parietal lobe) projects to upper retina.
The upper half of the visual field projects to the ________half of the retina. lower
The lower half of the visual field projects to the _________half of the retina. upper
Where do optic fibers cross? optic chiasma
In the optic chiasma, fibers will partiall cross so the left half of the visual field enters the right optic tract, and vice versa
Where do the optic tracts synapse? lateral geniculate body
LGB lateral geniculate body where optic fibers synapse after crossing/decussating in the chiasma.
Fibers from the LGB will form the OPTIC RADIATION
The optic radiation fibers from the upper half of visual field will form the Loop of Meyer in the Temporal Lobe
The Loop of Meyer optic radiation fibers from the upper half of the visual field that project from the LGB into the temporal lobe
Relating to visual, the temporal lobe contains the Loop of Meyer, which are the fibers from the upper half of the visual field
Fibers from the LGB forming the optic radiation from the lower half of the visual field will project to the parietal lobe
Lower visual field to parietal lobe
upper visual field to temporal lobe Loop of Meyer
The optic radiation fibers that formed the Loop of Meyer in the temporal lobe will terminate in the Lingual gyrus (upper part of visual field) which is the lower optic gyrus.
The upper visual field Decussate to contralateral in chiasma, LGB to optic radiation, form Loop of Meyer in temporal lobe, terminate in Lingual gyrus.
Optic radiation fibers from the parietal lobe (hence lower visual field) terminate in the Cuneus
The lower visual field decussate contralateral in chiasma, LGB then optic radiation, through parietal lobe, terminate in Cuneus
Cuneus has the __________ visual field projection. lower
Lingual gyrus has the __________visual field projection. upper.
Dust the R optic nerve R anopsia (complete loss)
Dust the optic chiasma Bitemporal hemianopsia (no peripheral vision)
Dust the R optic tract L homonymous hemianopsia (no left visual field on either eye)
Dust the R Lateral Geniculate Body L homonymous hemianopsia (no left visual field either eye)
Dust the R Optic Radiation L homonymous hemianopsia (no left visual field either eye)
pressure on Left optic chiasma due to occluded/enlarged Internal Carotid Artery ipsilateral (left, in this case) Nasal Hemianopsia if it's one carotid or Bilateral Hemianopsia if it's both carotids
What would cause a sagittal lesion to the visual system at the optic chiasm? Pituitary adenoma
lesion to R Loop of Meyer Left Upper Quadrant Homonymous Hemianopsia ("pie in the sky" temporal lobe lesion means you are always looking up towards contralateral side of lesion)
lesion to R temporal lobe Left Upper Quadrant Homonymous Hemianopsia ("pie in the sky" lesion to temporal lobe/loop of Meyer means you are always looking up to contralateral upper quadrant)
lesion to R optic radiation in Parietal lobe Left Lower Quadrant Homonymous Hemianopsia (the lower half of visual field projects to parietal lobe before ending in in the Cuneus, so a loss to parietal is lower opposite quadrant)
lesion to R optic radiation in temporal lobe/Loop of Meyer Left Upper Quadrant Homonymous Hemianopsia (temporal lobe/loop of Meyer receives from upper visual field, before ending in lingual gyrus. Lesion causes loss of contralateral upper quadrant, commonly known as the "pie in the sky" effect)
Optic radiation temporal lobe/loop of Meyer is __________ visual field headed to _________. upper, Lingual
Optic radiation parietal lobe is _________ visual field headed to _______________. lower, CUNEUS
Whenever the primary visual cortex (lingual gyrus/upper field or cuneus/lower field), what is spared? the macula
Lesion entire R primary visual cortex Left Homonymous Hemianopsia with sparing of the Macula
primary visual cortex Lingula (upper field), Cuneus (lower field)
lesion R lingual gyrus Left upper quadrant homonymous anopsia with sparing of the macula
lesion R cuneus Left lower quadrant homonymous anopsia with sparing of the macula
a medical term for a type of partial blindness resulting in a loss of vision in the same visual field of both eyes. Homonymous Hemianopsia
an oval-shaped highly pigmented yellow spot near the center of the retina of the human eye macula
http://cim.ucdavis.edu/EyeRelease/Interface/TopFrame.htm (eye muscle lesion) http://cim.ucdavis.edu/EyeRelease/Interface/TopFrame.htm (cranial nerve lesion to afferent/efferent path)
trace light reflex (11) which leads to constriction of pupil retina-optic nerve-optic tract-superior brachium-pretectal nucleus BILATERAL-Edinger/Westphal nuclei-CNIII Oculomotor-ciliary gang-short ciliary nuclei-ciliaris & sphincter pupillae muscles
which reflex causes pupillary constriction? light reflex (the loop with optic tract and superior brachium, LGB then to eye again)
trace accomodation reflex (15) retina-CNII-optic T.-lateral geniculate nucleus-optic radiation-visual cortex-frontal eye field-corticobulbar tract-pretectal nucleus BILATERALLY-Edinger/Westphal nuclei-CN III.-ciliary ganglion-short ciliary nerves-ciliaris & sphincter pupillae muscles
function of accomodation reflex convergence, thickening of the lens
high velocity eye movements that orient the eyes toward the stimulus saccadic movements
saccadic high velocity orientation of eyes towards stimulus
coordinates visual, somatic, and auditory info. when adjusting the head movement towards a stimulus Superior Colliculus (eye) and Frontal Eye Field
Receives information about motion in the visual field superior colliculus
concerned with motion in the visual field and ATTENTIVEness for identification of BROAD outlines superior colliculus
receives information from the primary visual cortex and is concerned with FINE visual discrimination and SACCADIC movement towards complex visual stimulii Frontal eye field
broad outlines of objects, a general id of objects in the visual field superior colliculus
Receives info from cortex and identifies the finer details of specific objects and is responsible for saccadic movements towards it Frontal eye field
white tough wall of the eye Sclera
thin lining over the sclera and inside the eyelids conjunctiva
clear continuation of the sclera over the iris and pupil cornea
composed of muscles which constrict or dilate the pupil Iris
part of the retina which is most sensitive and has the least number of vessels. Responsible for CENTRAL vison. Macula
2mm pit in the macula where all the retinal layers are shifted away so the image is received by the photoreceptors with the least amt. of distortion. Fovea
a hole in the iris controlled by muscles in the iris. Pupil
The blind spot. Contains no photoreceptors. Passageway of optic nerve and vessels. Optic disc
The macula and fovea are right on the dividing line of the retina between the ___________ retina and the ___________retina. nasal retina and temporal retina
structures on temporal retina side half of macula, half of fovea
structures on nasal side half of macula, half of retina, Optic disc (blind spot)
There are 3 sets of _________ and 2 sets of __________ in the retina. neurons, interneurons
How many sets of neurons in retina? 3
How many sets of interneurons in retina? 2
Deepest layer of cells in retina Photoreceptors
Intermediate layer of cells in retina bipolar cells (get it? They have two poles so they must be in the middle)
Superficial layer of cells in retina ganglion cells
What makes up the Optic CNII? axons of ganglion cells in superficial layer of retina
Light has to go through all the layers of the retina to reach the ________________. photoreceptors
2 kinds of communication cells in retina Horizontal & Amacrine
Cells in retina that allow communication between photoreceptors (deepest) and bipolar (intermediate) cells. Horizontal cells of retina
cells of retina which allow bipolar (intermediate) and ganglion (superficial) cells to chat each other up. Amacrine (amiable cells) of the retina
Why do horizontal cells and amacrine cells of the retina need to facilitate communication between the 3 layers of cells? Convergence and lateral inhibition
lateral inhibition inhibiting a neighboring cells
even though the picture shows the receptor cells as the outer layer, they are considered to be the deepest
high sensitivity to light (1000x) rods
concentrated in fovea cone
saturate in daylight rods
not present in fovea rods
low light sensitivity cones
night vision rods
high acuity cones
not light sensitive cones
day vision/color vison cones
1 type of photopigment (i.e., see in greyscale) rods
low acuity rods
concentrated in fovea cones
3 types of photopigment (blue, red, green) cones
single photon detection ability rods
night vision rods
more photopigment, capture more light rods
low photopigment cones
saturate in intense light cones
low acuity rods
high acuity cones
sensitive to light (1000x), single photon detection ability rods
not sensitive to light cones
night vision rods
day vision/color cones
up photopigment to capture more light rods
low photopigment (don't need more light because they see in the daytime) cones
saturate in day light rods
saturate in intense light cones
low acuity rods
high acuity cones
not present in fovea rods
concentrated in fovea cones
1 type of photopigment rods
3 types of photopigments (red, blue, green) cones
rods and cones are photoreceptors
2 types of photoreceptors rods and cones
2 types of retina peripheral and central
type of retina with MANY photoreceptor cells and MANY ganglion cells peripheral
type of retina with MANY rods peripheral (remember, rods see at night and in 1 photopigment)
type of retina with few cones peripheral
type of retina that is very SENSITIVE to LIGHT peripheral (rods can detect one photon - you'd want them to be your night vision where there isn't much light)
type of retina with many CONES! central (standard time is daytime!)
type of retina with low number of cones and low number of ganglion cells central
type of retina with NO rods. central
Membrane potential of retina in the dark (mV)? -40mV
product continuously produced in photoreceptor to keep sodium channels open and membrane at -40mV (a very low depolarization level, easily overcome - a "high alert" membrane potential) Cyclic Guanosine Monophosphate
CGM cyclic guanosine monophosphate
who makes CGM and where and why? CGM made by guanylate cyclase in the photoreceptor to keep Na+ channels open
light goes through all ________layers retinal
Light goes through all retinal layers and is absorbed by the ______________ epithelium. pigment
Light triggers absorption of the electromagnetic radiation (sun) by the ______________in the membrane of the stacked discs in the photoreceptor's outer segment. photopigment
where does light get absorbed in the pigment epithelium in the photopigments within the STACKED DISCS lying in the photoreceptor's outer segment
where are stacked discs? in the photoreceptor's outer segment - they contain the pigment of the pigment epithelium that absorbs electromagnetic radiation (sun) after it passes through all retinal layers. Photoreceptors are deepest, remember?
photopigment in rods RhODopsin
retinal, a derivative of vitamin A, is bound to an opsin, a 7-pass transmembrane alpha helices receptor protein like G-protein coupled reactions) RhODopsin, the photopigment in RODs
Cones have 3 ________ opsins
Young-Helmholtz trichomacy theory combination of relative excitation and inhibition of the red, blue and green opsins in the cones accounts for our color vision
what accounts for color vision excitation and inhibition of RGB opsins in the CONES (Young-Helmholtz theory of trichomacy)
Light bleaches half of the photopigment molecule in the rods called retinal (retinal + opsin = RhODopsin)
Light bleaches retinal
The bleaching retinal activates ___________, the other half of the RhODopsin molecule. opsin
When light bleaches retinal and this activates opsin, what G-protein is stimulated and where? Transducin in the stacked disc membrane
When light bleaches retinal, stimulates opsin, and activates Transducin in the stacked disc membrane, an effector enzyme called _______ breaks down cGMP. PDE (PhosphoDiEsterase enzyme)
When PDE breaks down cGMP, what happens? Sodium channels close! and the photoreceptor membrane HYPERPOLARIZES to -70mV.
What is the effect of Hyperpolarization of the photoreceptor membrane to -70mV when the Na+ channels snap shut? Glutamate level DECREASES
what neurotransmitter level decreases with hyperpolarization of photoreceptor membrane to -70mV? glutamate
When we go from a lit room to a dark room, the photoreceptor's sensitivity to light increases by _______________x. 1 million
Our pupils dilate when we go into a dark room and unbleached __________ regenerates in the rods via a process that requires Ca+ RhODopsin
When we walk into a dark room, our pupils dilate and unbleach rhodopsin regenerates in the ________ via a process that requires _____. rods, Ca+
area of the retina that, when stimulated by light, changes the cell's membrane potential. Receptive field
What happens when the Receptive field of the retina is stimulated by light? The Receptive Field changes the cell's membrane potential.
where are bipolar cells? intermediate layer
The receptor field, that can change a cell's membrane potential when stimulated by light, is full of __________ cells. bipolar
There are 2 areas of the REceptor field: 1. Center 2. Surround
photoreceptors that directly synapse with bipolar cells are located in the _________of the Receptor field CENTER (direct synapse with bipolar)
photoreceptors that synapse on horizontal cells which, in turn, synapse on the bipolar cell are located in the _____________of the Receptive field. surround
Direct synapse between bipolar and photoreceptors takes place where? in the CENTER of the REceptive field
indirect synapse by photoreceptor cells first on the horizontal cells, which then synapse on the bipolar cells takes place in the surround of the Receptive field
surround is indirect via horizontals
Center is direct between photoreceptors and bipolars.
The Receptive field centers are _____________. Antagonistic
If the surround Receptive field (indirect) is ON, then the center Receptive field (direct) is _____. OFF
Antagonistic receptor fields surround and center are never on at same time
In either case of surround-ON/center-OFF or vice versa, what are the bipolar cells doing? depolarizing
ON bipolar cell means the cell depolarizes when light is on
When a bipolar cell depolarizes when light is ON, less ____________ released by the photoreceptors. glutamate
Which cell in retina releases glutamate? photoreceptors
What kind of receptors on the ON-bipolar cell causes depolarization? G-protein coupled GLU receptors
what kind of receptor is on the membrane of a bipolar cell for ON (light depolarization)? G-protein linked Glutamate receptor
In an OFF-bipolar depolarization, the cell depolarizes when light is OFF. In this case, more ________ is released by the photoreceptors. Glutamate
What kind of receptor is in the bipolar cell membrane for OFF (dark depolarization)? glutamate-gated direct ion channels
What is the neurotransmitter of the retina? Glutamate
In either ON (light depolarization) or OFF (dark depolarization), what neurotransmitter causes the depolarization of the bipolar cell? Glutamate
Where are ganglion cells in the retinal 3 layers? most towards surface of retina
Like bipolar cells, ganglion cells also have ___________ receptive fields. Antagonistic
Antagonistic receptive fields are found on both bipolar and ganglion cells.
How do ganglion cells react to light? They "gang up on it" with a barrage of Action Potentials
The response to stimulation of the center receptive field of ganglion cells may be canceled by the ? response of the surround receptive field, hence antagonistic
Ganglion cells in our retinas are responsive to differences in ________________ within their receptive fields. ILLUMINATION within their receptive fields
2 types of Gang members in the retina M & P (Magnocellular & Parvocellular)
Ganglion cell with large receptive fields, responds to MOTION and low contrast stimuli, ergo they aid in LOW RES vision Magnocellular Ganglion
Ganglion cell that has a small receptive field, color opponent cells (sensitive to wavelength). Red-Green-Blue-Yellow. Responsible for COLOR VISION ergo fine detail discrimination. Parvocellular ganglion
cells which detect motion and broad outlines parietal
area in brain where image appears visual cortex
lobe which detects shape, form and color Temporal
cells responsible for forming optic nerve (CNII) ganglion
If Weber's test is performed and there is lateralization, do you still have to perform Rinne's test? yes, always both
where is the superior cerebellar peduncle in the midbrain
responsible for central vision macula
When pupil is introduced to light on either side but neither constrict, what is damaged? Oculomotor n. CNIII
What causes bitemporal hemianopsia? pituitary adenoma (presses on optic chiasma)
lesion to R optic tract Left homonymous hemianopsia because it has decussated so contralateral
describe layers of retina by cell from outermost to deepest Outermost: ganglion cells that make up CN I Optic nerve. Middle: bipolar cells. Deepest: Photoreceptors
Does light have to travel through all the retinal cells layers to get to the photoreceptors? Why? Yes, because they are deepest.
Cells that make the bAg of the retina b for bipolar, A for Amaracrine, and g for ganglion. This is how you remember the Amaracrine are between the bipolar and the ganglion cells.
What cells are between the photoreceptors (deep) and the bipolar (middle)? Horizontal
What makes up the optic nerve axons of the ganglion cells of the superficial layer of retina
cones are NPT light-sensitive. They are for seeing when the sun is out.
cones _____________ in intense light saturate
cones have ___ types of photopigments 3 (RGB)
rods are very light sensitive. They are for seeing in the dark. If you are walking in the dark, it helps to carry a big rod.
rods are used at night
rods only have one type of photopigment (who needs colors at night?)
rods saturate in plain old daylight. Outta here! They are vampires. Vampire Rod - no bright lights, please.
Which do we use for night vision, our peripheral retina or our central retina? Why? peripheral, because it is heavy on the Vampire Rods and the photoreceptors for even the smallest amt of light detection but it has no cones so it sucks at details. Cones are for outlining the details of life. Vampire Rod is only interested in the night.
Cones are for __________ the details of life. outlining. They are good for detail/discrimination.
What structure has lots of cones, no rods? Central retina
The central retina has lots of _________for outlining details. cones.
Does the central retina have any rods? no, Vampire Rod isn't interested in details.
Vampire Rod lives on the periphery, in the peripheral retina, sensitive to the tiniest bit of ligt (lots of photoreceptors) and able to detect the motion of even a single passed out photon from 500 yds. Tell me about him. Vampire Rod - no details, lives in the peripheral retina, night vision, lots of rods and photoreceptors and ganglion in his world. Saturates/afraid of plain old daylight. 1000x more sensitive to even 1 photon. V.R. is phobic of the fovea.
The central retina is like a Disney film, full of color and details and bright light, all marked off carefully by a ring of _______. cones
CCR does not mean creedence clearwater revival; it means: Central cones retina
light waves becoming actual photoreceptor potential (photons to chemical energy) is called PhotoTRANSDUCTION
membrane potential of retina in the dark -40mV!!!!
It is very exciting to Dr. T that the membrane potential of the retina in the dark is -40mV!!!
an enzyme in the photoreceptor cell (deepest layer) continuously keeps the ____ channels open so that the membrane potential may remain at _____!!!!! in the dark. Na+, -40mV
Cyclic guanosine monophosphate is continuously produced by the photoreceptor enzyme ____________________, keeping the sodium channels open (-40mV). guanylate cyclase
how does the photoreceptor keep the membrane potential so low? It does it with a little bit of bat ________. guano! (keeps Na channels open and membrane p. at -40mV!!!)
Name the 3 layers of the retina and the interneurons again, from outermost to deepest: ganglion are outer, then Amacrine, then bipolar in the middle (bAg), then Horizontal, then deepest are photoreceptors
Light goes through all the retinal layers (3) and is absorbed by the pigment epithelium
What absorbs light after it gets through all the layers? pigment epithelium
pigment epithelium? PE is the layer which convinces the photopigment lying in the stacked discs of the photoreceptor layer to take in the poor wandering electromagentic radiation (light) which traveled all that way. Pigment Epithelium is guilt.
What does Pigment Epithelium do? PE is guilt - it convinces the deepest photoreceptor photopigment to absorb/take in the electromagnetic radiation into the stacked discs.
Where are stacked discs and what goes in there? in the photoreceptors' outer segment. Inside stacked discs live miserly photopigments who, when guilted into it by Pigment Epithelium, will take in/absorb electromagnetic radiation that did, after all, come through all those layers of retina.
Where does photopigment live? in the (highrise) stacked discs of the outer segement of photoreceptors
Remember Vampire Rod who sees not very well but has night vision and lives in the peripheral retina? He can detect a single photon of light. In V.R's photoreceptor outer cape, he has only one assistant photopigment in his stacked discs: Rhodopsin (like Renfield, only smaller- if you don't know who Renfield is, you need to watch a real vampire movie instead of twi-lite)
The only personal photopigment assistant Vampire Rod has in his stacked discs? Rhodopsin
What is rhodopsin and where is it? retinal, a derivative of Vitamin A, is bound to an opsin which is a 7-pass G-protein linked/coupled receptor. Rhodopsin is found in the stacked discs of the outer cape of Vampire Rod the Photoreceptor. It's his only photopigment/assistant for night!
Vampire Rod has his assistant Rhodopsin; what do cones have? 3 opsins and this excitiation of the three (RGB) opsins accounts for our color vision, according to the Y-H trichromacy theory
The cones are for outlining details and color in broad daylight (think Disney movie) - what do they have, according to the Young-Helmholtz theory of tricromacy, that allows us to see in technicolor? 3 opsins (Red, Green, Blue) that get excited or inhibited, accounting for our color vision.
The 3 little RGB opsins live in the bright, sunlight, detailed world of Disney _________ photoreceptors. cones
An opsin is a 7-pass transmembrane alpha helices receptor protein like G-coupled receptors
How many opsins live at Disney world cones? 3
How many opsins live with Vampire Rod? just one: Rhodopsin which is retinal + opsin
Vampire Rod has Rhodopsin in his stacked discs - what happens when PE convinces the photopigment Rhodopsin to take in the electromagnetic energy of light, considering it might be just one little ol' photon having come all that way in the dark? The light/photon "bleaches" the retinal A, and once that's out of the way, Opsin can get activated!
Now that retinal is bleached out of the way (ie, half of the Rhodopsin is gone), the opsin of the Vampire Rod photoreceptor wakes up. What happens next? Transducin (remember we are following phototransduction cascade) is a G-protein stimulated by opsin waking up. Transducin activates his PDE to break down cGMP (cyclic bat Guano-mono phosphate shit).
Retinal bleached. Opsin awake. Calls Transducin. Transducin gets on his ______ and breaks down bat __________. PDE, cGMP
What happens when PDE breaks down bat cGMP? The sodium channels close and the Photoreceptor (Vampire Rod) membrane HYPERPOLARIZES (shuts the casket lid) and turns down the juice to -70mV. This means less and less glutamate is released. Sleepy time.
When cGMP is broken down by PDE, what closes? SODIUM channels! When Na+ channels close, Vampire Rod's photoreceptor membrane hyperpolarizes to -70mv and V.R. shuts the casket lid - he's not getting any glutamate now. Decrease. Sleep. Hyperpolarize. No salt, no glutamate, no Chinese food.
How do ganglion cells, the outermost cells of the retina, react to light? with a BARRAGE OF ACTION POTENTIALS!
The response of ganglion cells in the center may be ___________ by the response of the surround and vice versa. cancelled/lateral inhibition
because the response to stimulation of the center ganglion cells may cancel out the surround ganglion cells, we can say the ganglion cells in our retinas are mainly responsive to differences in ___________ within their receptive fields. illumination within their receptive fields (in other words, the center cells see light and the peripheral cells see, well, dark, and neither wants to swap jobs)
respond to LARGE receptive fields~ Magnocellular
respond to s m a l l receptive fields~ p a r v o cellular
2 types of ganglion cells MAGNOcellular & p a r v o cellular
large receptive fields, respond to object motion and low contrast stimuli - aid in low contrast vision MAGNOcellular (these live out in the periphery with Vampire Rod photoreceptor and his sidekick Rhodopsin, casting large nets for a photon here and there in low or night light)
Vampire Rod photoreceptor picks up motion in peripheral vision, esp. in low light. What ganglion cell compliments V.R. at night? MAGNOcellular ganglion (wide net casting for sometimes single photon to pounce on)
ganglion with a small receptive field, color opponent cells that are sensitive to wavelength, RGB+Yellow! so responsible for color vision, Disney style! Discrimination of fine detail, color, bright lights baby! p a r v o cellular ganglion (in conjunction with Disney cones that live in the center of the retina and illuminate the world!)
LGN lateral geniculate nucleus
how many layers of LGN are there? 6 going from back to front
how are the 6 layers of the LGN numbered? back to front
Which LGN layers contain MAGNOcelluar ganglion (the wide nets for object motion and low contrast stimuli at night)? 1,2 layers contain M-type (MAGNO) cells and receive synapses from M-ganglion cells
cells furthest in back of LGN MAGNO for night vision and motion detection (M-type cells and M-type ganglion)
Layers 2-6 of LGN contain what type of cells? p a r v o -type (P-type cells receiving synapses from P-type ganglion)
LGN magnos are found where? layers 1,2 (all the rest are p a r v o)
LGN layers that receive fibers from ipsilateral retina 2.3.5
It's 2:35pm - what side of your LGN is getting a call from the retina? The same side! (layers 2.3.5)
if the ipsilateral side of retina sends fibers to LGN layers 2.3.5, obviously the contralateral retina sends fibers to LGN layers _________ 1-4-6
If the brain is a tonotopic reflection of the body, and the LGN has 6 layers, how many layers does the primary visual cortex have? 6
area 17 striae cortex/primary visual cortex
the Primary Visual Cortex (PVC -hahahaha!) is found in Area ____ at Lowe's home store. 17
What aisle is the PVC in at Lowe's home store? aisle 17 has PVC
There are 6 ________________layers of PVC/area 17 histological
Where do areas I and II of visual cortex get their info? LGB, ja rule!
Where does area III get its info? III is P! III is P! and it goes everywhere if you P in the pool. (all other cortical layers)
From what cells does area IV get its information? M & P from the LGB, word.
Area V is a Superman jive - he can ___________ you wit' a look from his eye. pulverize (pulvinar and superior colliculus to V)
Like I and II, VI is straight LGB, fool! Don't f*** with Santa __________. Claus(trum)
I & II from LGB. III got P going everywhere, see? Yo! IV-abc get M&P from the LGB, word. Area V is da Superman jive - he can pulverize you wit a look from his eye. Like I & II, VI is straight LGB, fool! Don't f*** with Santa Claus. Uh.haha!Uh. I & II: LGB, III: P to all cortical areas, IV-abc: M&P from LGB, V: Superior colliculus + pulvinar, VI: LGB + Claustrum
Layer IVc is organized into alternating ocular __________ _____________ dominance columns
LGB fibers from one side (ipsi) of the retina are going to end up in the __________ next to the lateral geniculate body fibers from the contralateral retina. Primary Visual Cortex (PVC)
LGB fibers from the same side (ipsilateral) retina are going to end up in the primary visual cortex next to the LGB fibers from the __________ retina. contralateral
The PVC (yes, plumbing pipes) receives the ___-type cells and streams the channel through V2 (area 18 & 19) to the parietal cortex for analysis of motion. M
Where does the PVC shuttle M cell channels? Why? PARIETAL cortex for Motion analysis (M for Motion analysis)
Motion analysis is done in the __________ cortex via the ___-cells. Parietal, M-cells (remember Magnocellular are associated with Vampire Rod in the Periphery an see in the dark to detect a rat moving, in case V.Rod wants to eat it)
Oh no, Interblobs!!!! agghhhhhhh!!!!!! shape
and baby Blobs! agghhhhh!!!!! color
The primary visual cortex separates ___ -type cell information (detail Disney bright as day parvocellular stuff) into two basic Disney creatures: Interblobs and Blobs!
The Disney monster Interblob detects shape
The Disney creature Blob likes color
The PVC separates P-cell (parvo Disney bright acuity detail) info into shape and color. What monsters receive shape? color? shape is Interblob! color blobs.
The P-type (parvo detail) information is separated in the primary visual cortex. What happens then? Shape ends at an Interblob! while color stops in a Blob. These 2 channels are streamed through V2 to the TEMPORAL cortex for shape & color perception and visual memory.
Parietal gets M-cell Motion, Temporal gets P-cell shape and color. What else does temporal get via the Blob and Interblob guys? visual memory
Shape, color, visual memory - where? temporal lobe via P-cell (bright detail Disney)
I can't make this stuff up: where does color end in the temporal lobe? in a Blob.
I can't make this stuff up: where does shape end in the temporal lobe? with an Interblob! aggghhh!!!!
Where does visual memory get processed? Temporal lobe with shape and color (Interblob and Blob) via P-cell
Created by: hecutler