Special Senses (PDF)

I Chemoreceptions smells taste special senses...

I Chemoreceptions smells taste special senses I · smell/olfaction:1 ofoldestsenses ↓ receptors located in Taste (Gustation):linked to smell ·tastelgustation:combo of 5 senses complexsensory organs ·sweet, sour, salty, bitter ? Umani of the head ⑨ Umani:amino acid glutamate. * ↳ smell Olfaction: ↳ taste ·linked to emotion ↳ vision sour, triggered by Ht memory ↳ hearing olfactory cells in epithelium ↳ equilibrium ion in body fluid closely regulated ↳ In nasal cavity ↳ projectinto olfactory bulb > salty triggered by Nat ↳ olfactory cells live (months ion in body fluid closely regulated then new axons find way to bulb. v sweet associated:glucose Gustation: nutritious food primary gustatory neuron Olfaction: 2. cranial nerve VII, IX, X rodorants bind to odorantreceptors umani- nutritious food 3. synapse in medulla ↳ G-protein cAMP-linked membrane receptors - 4. thalamus 2. Activates Got bitter 5. -> WARNING:toxic Gustatory cortex 3. 4 cAMP (2nd messenger) 4. CAMP-gated cation channel opens I Receptors all over oral cavity · 3. Depolarize cell (+1 But mostly tongue 6. Signal passes along axon buds:taste cell + support cell I reaches bulb. I bud:50-150 taste cells cells non-neural - polarized epithelial =microvilli (4SA) =protein receptor (chanel * =I cell I taste I cell types - V r Type III receptor release ATP : ⑳ & Type III/presynaptic release serotonin extr9: & cravings:physical, psycho, cultures environmentfactors * spice:Somatosensory * saltappetite:lack Nat  2 The ear: ·perilymph in vestibular? tympanic duct-similar to plasma ·endolymph in cochlear duct-secreted by epithelial cells hearing, perception of energy carried -similar I our to ICF 4[k + ] = by sound waves -Freceptive field BUTsensitive to different frequencies -brain differences rather further distance uses timing than neurons to localize sound, takes longer sound waves: >10W, soft sound uncoiled cochlea: -high;and sound Transduction: hearing has multiple steps: complex s de E I air "red - filled fluid filled inner ear ↳ cochlea & ume men cross-section ofcochlear: 3 sensory coding for loudness: -loudness coded in somatic same way as strength (intensity receptor -lorder:more receptors/hair cells activated:more rapid action potentials in sensory neurons. create movementof mem. r sound wave frequency determines displacement basilar membrane of location of active hair cells makes code with info on pitch example ofhair cell: signal transduction in hair cells: sensor coding for pitch: *basilar membrane - variable sensitivity to sound distal wave frequency along length -end 7 nigh basilar ION oval helicotrema membrane window flexible stiff region region  Auditory pathway: 4 otolith move in response to gravity lacceleration ~ each side ofbrain ↳ sense linear acceleration I head position. (cochleal into from both gets -> primary neurons sides over 3 cross - -> and neurons normal pathway. Hearing loss:.. conductive transmission in external/middle central damage neural between 9 2. path ear cortex. 3. Sensorineural:damage inner ear cochlear implant 2. EquiliDriUM:State ofbalance components dynamic movementin space static is head in normal, r - upright position - vestibular apparatus (membranous labyrinth) a semicircular canals (3) otolith organs (2 sac-like) N pathway projectto cerebellum -> vestibular apparatus: -connected fluid-filled =>> Nat chambers 1 2 endolymph -into movement position in space. + on  semicircular canals: E sense rotational rotation - Otokinetic nystagmus -> ofhead acceleration * during spinning:vision fixed Ispinning) :Why not dizzy? ↳ vestibular stimulate apparatus -endolymph in ampulla moves ↳feel vertigo/dizziness with head rotation ↳ inhibits hystagmus -stops as dancer holds head still... less inertia than if always Optokinetic reflex we follow object - can turning ⑤- even with stationary head ·optokinetic nystagmuscaused by movement of visual field (train) large across refind purpose - fixate gaze on objectfor period 3 itis infrontofeyes then flicking eyes forward to fixon new part ofscene. ·relatively stationary scenes I a smear on retina Physiological Nystagmus > involuntary eye movement that's part of vestibulo- ocular reflex (VOR) nystagmus - repeated back-and-forth Pathways for equilibrirm: movement slow other one way t flicks back quick way ↳ stabilizes images on retina head during movement.  6 * Vision: En lightenters eye ↳ pupil regulates amountoflight e ↳ focused on retina by lens photoreceptors transduce light energy (electrical signall -electrical signal (processed through neural path) Pupil regulates amountlight. Neural Pathway: external Anatomy 7 Neural Pathway: -> re+ind  7 The lens Phototransduction atRetina: - focus the light -concave lens scatters rays ①D common visual defects: accommodation -convex lens converges rays presbyopid-loss · of Ifocal length distance = from Clens-flexible:flatalways) corrected centre of lens to focal point. · myopia -near-sighted (curvature 3 with a ⑧ or too long eyeball) falls short concave lens paint · hyperopia-far-sighted (flat corner 7 corrected with a or shorteyeball falls lens (glasses) Yength too far convex astigmatism corned perfectly · -> - far objects -> parallel rays shaped dome. flattened lens -> broader -> focal retina 2 ↑ night2 pointfalls on * at 3 & -close objects -> raystparallel -> lens unchanged ↑ -> focal point on reting ↳ +00 -> objectunclear long a -close object -> rays parallel - :differentlength = -> lensrounded differentcolour 2 focal length -> shorter -> tocal A pointon retina -> clear object - Accommodation -> eye adjusts shape in oflens to keep object focus & most layers & lens attached to ciliary muscle transparent by ligaments (convles) -> receptors embedded here  8 Phototransduction in rods -> no light: field Centre & small receptive very sensitive. second receptive field:bigger:less sensitive. -> Outer dred black ↑ White cones 3 rods:look and function rods - similarly lower intensity (night. cones day - time -> colour.  9 * cross-section. processing of light:  Visual field NB: color-blindness: -on X-chromosome mostly men - - show red green number -> colour blind sees 378 3 2 = 5. look with · Edge detection eye:2D r look with y -> makes white block show eyes:3D monocular ganglion cell visual (Receptive field: reversed colours (red -> adaptations cones Afiring it long stimulusl* opponent-colour theory (in white light, green comes send message through red-green channel (unopp used) g 4 color opponentganglion cells centres surround with - separate color opponent properties I : red-green 18