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49 Cards in this Set
- Front
- Back
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Where are chemoreceptors houses |
tastebuds, oral cavity and throat |
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Taste buds consist of |
1. Taste pore - opening which fluids in mouth come in contact with surface of receptors 2. Taste receptor cells -modified epithelial cells with microvilli -pl.mem has receptor site that selectively bind |
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How do receptor cells respond to taste |
use different pathways to bring about depolarization for each of the 5 categories |
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Taste brain centers & roll |
1. Hypothalamus & Limbic system - unpleasant and pleasant taste - behavioral responses 2. Cortical gustatory -preception of smell and taste |
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To be smelled, substances must be |
1. sufficently volatile that molecules enter nose 2. water soluable to be dissolved in muscus |
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How are afferent smell signals sorted |
Glomeruli within olfactory bulb |
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How do odourants trigger action potentials |
through second-messager systems |
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Smell brain centers |
1.Limbic system - behaviors associated with smell 2. Cerebral cortex -perception and discrimination of taste |
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What taste do infants prefer |
sweet over bitter and sour - bananas and chocolate will relax baby |
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is smell fully developed at birth |
yes |
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Aging and smell/taste |
-smell declines more then taste -sweet remains but the other decline -medications and disease reduce smell and taste |
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What light rays do we see |
btw 400 and 700 |
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What produces convergence of diverging light rays |
convex surface |
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What causes refraction |
light rays slow down as they pass through a dense medium and change course ** no refractions from air to glass |
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Accomodation |
ability to adjust the stregnth and shape of the lens |
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What adjusts the lens |
ciliary muscle and suspensory muscle |
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Lens shape in far vision |
flat, weak -relax cilary muscle -taut suspensory ligament |
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Lens shape in near vision |
rounded, strong -contracted ciliary muscle -slack suspensory ligament |
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presbyopia |
age-related reduction in accomadation ability of lens |
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emmetrophia |
strength of lens is increased by accomodation to bring a near source into focus (rounded) |
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Myopia |
person has better near vision then far vision |
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hyperopia |
person has better far vision then near |
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What forms the optic nevre |
axons of ganglion cells |
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where does the optic nerve leave |
optic disc |
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why is there a blind spot (optic disc) |
no image can be detected here because of lack of cones and rods |
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fovea |
-depression in center of retina -point of most distinct vision -only has cones |
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Macula lutea |
-area surrounding fovea -high acuity |
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Macular degeneration |
-lead to blindness -dougnut vision |
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Color Vision |
1. object viewed as BLUE does not stimulate RED or GREEN 2. each cone is activated by a diff wavelength 3. yellow is 83:83:0 red:green blue not excited at all 4. |
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What makes white, what makes black |
white - mix of all wavelengths of light black - absences of light |
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Normal conversation is how many db |
60 |
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Vestibular Appartatus is found where? and consists of what |
Inner Ear A. Semicircular canals - detect rotation in any direction b. Utricle and saccule - detect change in linear movement -determine head position |
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Ear is developed from what embroyonic layers |
ectoderm, mesoderm, endoderm |
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startle reflex |
will appear with high pitch sounds |
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infant pitch of sound |
within normal range - no whisper or high pitch sound can be discerned |
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Is ex. ear fulled developed at birth |
no - ex. ear canal exposed |
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when do babies hear like adults |
6 months |
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what affects earing at birth |
fluid in middle ear |
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Eustacian tube |
connects middle ear and nasopharnyx equalize pressure shorter in children, narrow and horizontal in adults - air movement more difficult |
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Aging Ex. ear |
cartilage continues to grow hairs gets longer and thicker - doesnt affect hearing waxy secretion (cerumen) builds - causes deafness |
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Aging Middle ear |
flexible elastic tissue replaces with collagenous tissue making eardrum thinner and less resilent auditory ossicle may calcified and harded - interfering with soundwave transmission from tympanic to oval window |
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PRESBYCUSIS |
with aging and lifetime noise - reduction in high pitched sound |
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Sensory prebycusis |
atrohpy and degrenation of receptor cells - loss of hearing at high frequency |
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Neural prebycusis |
loss of neurons in auditory pathway results in speech discrimination |
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metabolic prebycusis |
caused by diminished supply of nutrients to receptor |
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mechanical prebycusis |
atrophy or stiffening of structures in receptive area (hair) results in hearing loss from low to high frew and eventually interfer with speech |
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Hearing loss can be either____ or _____ |
conductive hearing loss or sensonneural |
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Connductive hearing loss |
changes to outer/middle ear: impacted cerumen middle ear infection tumor perforated tympanic mem lack of mobility in ear ossicles *** hearing aid may help |
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sensorineural hearing loss |
problem with cochlea and auditory nerve ** hearing aid can not help - cochlear implant may help |
