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85 Cards in this Set
- Front
- Back
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Coloboma
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defects in eye from failure of the choroid fissure to close
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Peter’s anomaly
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defects results from a lack of separation of the lens vesicle from the
corneal epithelium |
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during optic cup patterning, this regulates transcription factor expression in dorsal retina
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BMP4
Upregulates tx5 Downregulates Vax and Pax2 in the dorsal retina Tbx5 upregulates ephrin B1 & ephrin B2 dorsally Lance: We have no Idea what we are tying to say about slide 40 from lecture 13 |
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Ventroptin,
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BMP4 inhibitory protein
prevents BMP4 from interacting w/cells of the Ventral retina |
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regulate transcription factor expression in ventral retina during optic cup patterning
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Shh & RA
Upregulates Vax2 Downregulates BMP4 |
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These genes for retina development are expressed early in the anterior neural plate
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Pax6
Six3 Rx Lhx2 |
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Surface Ectoderm develops into
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Lens
Corneal Epithelium |
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mesenchyme develops into
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Corneal Stroma
Uvea: (choroid, iris, ciliary body) Sclera vitreous CT, muscle (& vessels) come from cranial mesenchyme |
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Neural Ectoderm develops into
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RPE
retina optic nerve |
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these TF can cause ectopic eye formation
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Pax6
Rx Six3 |
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if you KO these you will get cycloptic embryos
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cyc
shh |
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retinal progenitor cells (RPCs)
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E10.5, during lens placode invagenation
Undifferentiated, express common eye TF Pax6, Rx1, Six3, Six6, Lhx2, Hes1, chx10 multipotent & differentiate into ganglion cells, bipolar, amacrine, horizontal , photoreceptors and Müller cells glia. |
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what are the dorsal regulators in Dorso-ventral axis of the retina
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BMP4
Tbx5 |
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what (TF) & where BMP4 in Dorso-ventral axis of retina
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Dorsal
upregulates tx5 down regulates Vax & Pax2 |
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what & where Tbx5 in Dorso-ventral axis of retina
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Dorsal
upregulates ephrin B1, ephrin B2 down regulates EphBs |
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Ventral regulators in dorso-ventral axis of retina
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Shh
Retinoic Acid |
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Shh & RA in Dorso-Ventral axis of retina
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Ventral
Upregulate Vax2 Downregulates BMP4 Ventropin is found ventrally & binds BMP4 to further inhibit it |
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Vax2 in Dorso-Ventral axis of retina
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Ventral
upregulates EphB2, EphB3 down regulates Ephrin Bs |
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Ephrin Bs and Eph Bs
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control the lateral-medial axonal Targeting once the axons have reached the tectum
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Optic Stalk from optic vesicle
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Floor plate, prechordal plate releases Shh (& BMP7) --> induce Pax2
Pax2 down-regulates MITF & CHX10 |
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Retina from optic vesicle
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head ectoderm releases FGFs --> induces CHX10
chx10 down regulates Mitf & Pax2, |
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RPE from optic vesicle
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TGF-beta from periocular mesenchym
upregulates MITF downregulates Pax2, CHX10, & otx2 |
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what causes the eye field to split
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cyc controls expression of BMP7, Shh, twhh --> differentiation of the floorplate of the forebrain
Activates Pax2 (optic stalk) Represses Pax6 & Rx (retina) |
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Lens placode does what for optic cup
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secretes FGFs that turn on Chx10 & Lhx2
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these are high medially in the naso-temporal axis of retina
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BF2(foxd2)
SOHo1 (turns on EphrinAs) GH6 --> high EphA |
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nasal TF of naso-temporal axis of retina
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[high] BF1 (foxg1)
[low] BF2 (foxd2) |
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Tectum axis
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EphA3 controls Anterior-posterior
Ephrin Bs and Eph Bs control the lateral-medial |
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5 components to Chemoaffinity
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1. neurons are different
2. different b/c retinal position 3. differences are biochemical & expressed on membrane 4. differences are present when in early development when connections are formed 5. pre/post synaptic have complementarty markers that are selectivly exclusive |
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Glu receptors 3 types
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AMPA
NMDA Metabotropic |
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AMPA
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ionotropic: directly gates ion channels
binds agonist AMPA or kainate Na+ & K+ |
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NMDA receptor
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ionotropic
Ca+, Na+, & K+ ligand AND voltage- ated channel long term changes based on stimulation bursts from Pre Enhances Occular dominace columns |
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NT4/5 & BDNF
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causes loos of occular dominance columns
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slave ossiclators
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cerebral cortex
liver kidney |
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Properties of Circadian rhythem
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1. ubiquitus
2. generated by endogenous ossicaltors ~ 24hr 3. can be reset, phase shift by zeitgeburgs (external cues) 4. temp compensated (rate of clock genes, but not presents of clock) 5. genetically determined (tau) 6. clock based on molecular feed back loop |
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Entrainment
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critical aspect is timing of light to relative to rhythm
phase shift sets the period of internal clock |
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Melatonin
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released at night
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Light Pulse at begingin, or end of dark cycle
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phase delay
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Light Pulse at end of dark cycle
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phase advance
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Superchiasmatic nucleus effectors
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Temp
Adrenal Gland: Cortisol Penial Gland: melationin |
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zeitoburg receptors
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inner retina, glial cells
Melanopsin Crytpochrome/B2 cofactor |
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Crytpochrome
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1 & 2
1 more important xpressed in INL & Ganglion cells, & in the SCN |
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Melanopsin:
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TM protein
in small group of RGC dendrites |
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clock genes
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Per – period
Tim – timeless Dbt – doubletime Cry - cryptochrome |
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Clock molecular mech
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Per & Tim are inhibit Clk & Cyc at night, but Clk & Cyc inhibit Per & Tim during the day from entering the nucleus
complex with clk & Cyc, & Bma! affect gene transcription |
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Clock mid day
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CLK and CYC active (+ PER and TIM)
• PER unstable - DBT (doubletime) phosphorylates PER • CRY degrades TIM as long as light is present |
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Clock dusk
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Tim accumulates & displaces DBT
Tim (nuclear signal) |
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Clock midnight
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Per & Tim in nucleus, bind Clk & Cyc
--> Per & Tim mRNA decreases, --> Clk mRNA increases |
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Dawn Clock
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Perception of light by CRY
• Degradation of TIM • Phoshorylation and degradation of PER |
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Phase advance mech
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light near end of dark cycle will destroy Tim
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Phase delay mech
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Light after dusk by postponing production of Tim
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Melatonin regulation pathway
Retinohypothalmic tract |
RGC ->
RHT Retinohypothalmic Tract --> SCN --> PVH) PeriVentricular nucleus (IML) Interomediolateral cell column of spinal cord --> SCG superior cervical Ganglion Pineal gland mealatonin feeds back to hypo |
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Melanopsin:
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TM protein
in small group of RGC dendrites |
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clock genes
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Per – period
Tim – timeless Dbt – doubletime Cry - cryptochrome |
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Clock molecular mech
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Per & Tim are inhibit Clk & Cyc at night, but Clk & Cyc inhibit Per & Tim during the day from entering the nucleus
complex with clk & Cyc, & Bma! affect gene transcription |
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Clock mid day
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CLK and CYC active (+ PER and TIM)
• PER unstable - DBT (doubletime) phosphorylates PER • CRY degrades TIM as long as light is present |
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Clock dusk
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Tim accumulates & displaces DBT
Tim (nuclear signal) |
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Clock midnight
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Per & Tim in nucleus, bind Clk & Cyc
--> Per & Tim mRNA decreases, --> Clk mRNA increases |
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Dawn Clock
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Perception of light by CRY
• Degradation of TIM • Phoshorylation and degradation of PER |
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Phase advance mech
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light near end of dark cycle will destroy Tim
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Phase delay mech
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Light after dusk by postponing production of Tim
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Melatonin regulation pathway
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RGC ->
RHT Retinohypothalmic Tract --> SCN --> PVH) PeriVentricular nucleus (IML) Interomediolateral cell column of spinal cord --> SCG superior cervical Ganglion Pineal gland |
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Geniculo-hypothalamic tract- melatonin pathway
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RGC
LGN [IGL=Intergeniculate Leaflet] hypothalamus NPY & GABA |
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Features of Circadian Imbalance
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Sleep Disturbances
2. Carbohydrate Cravings 3. Confusion/Poor coordination 4. Malaise/Blues 5. Susceptibility to Infectious Disease |
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inner ear
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Vestibule - vestibular system
2. Semicircular canals - vestibular system 3. Cochlea auditory organ |
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Scala tympani and scala vestibuli
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perilymph
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Scala media
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endolymph, K+
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Inner hair cells
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Linear
supported by pillar cells |
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Outer hair cells
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V-shaped palisade
supported by Dieter cells (phalangeal cells) |
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hair cell innervation
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Afferent- spiral ganaglion cells
Efferent: reguates sensititivy |
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bass
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Excites near apex
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high pitch
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excites near base
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Hair cell transduction
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movement-> intake Ca 7 K+
Voltage change --> K+ Glu released in graded to afferent & efferent |
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phase locking
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phase @ nerve fires the same
compression as freq rises, nerve can't fire as fast, but keeps phase |
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population
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# of nerves firing, increases w/sound level
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CNS gets info about freq
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place code
where on basilar membrane hair stereocilia differ in length & stifness differ ion channels Temporal code phase locking- sync w/part of wave but not whole Volley Principle; get many different parts to get full wave |
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Place Code & Temporal code interact
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Place codes cant do bass, eaiser to phase lock lower freq
Temporal cant do pitch |
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hair cell adapt
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intersital plaque holds hairs together
hairs move -> Ca & K in Calmodulin active & releases myosin plaque slides down & hairs separate |
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conduction deafness
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vibrations cant get to inner ear
wax ruptured drum ossification |
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Sensorineural deafness
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damaged hair cels or auditory pathway
result of age & loudness |
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Chochlear implant
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electrodes implanted in Scala tympani
directly stimulates nerve fibers on basilar membrane |
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Otits MEdia
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ear infection
upper respriatory viral swollen Eustachian tubes Effusion of middle ear provides nice medium for bacterial growth |
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Retino-tectal mapping
Nasal has this & looks for |
nasal has low EphA
looks for High EphrinA in Posterior |
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Temporal looks for
Retio-Tectal mapping |
Has high EphA
looks for low EphrinA in Anterior Tectum |
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Dorsal
Retio Tetctum mapping |
Has Low EphB
looks for High EphrinB in Medial tectum |
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Ventral
retina tectum mapping |
has high EphB
Looks for low EphrinB in lateral tectum |
