| Term 
 
        | special sensory receptors |  | Definition 
 
        | distinct, localized receptor cells in head; vision, taste, smell, hearing, equilibrium |  | 
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        | 70% of body's sensory receptors here; processing by nearly half of cerebral cortex; protected by cushion of fat and bony orbit |  | 
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        | three layers of the eyeball |  | Definition 
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        | fibrous wall; anchor point for muscles |  | 
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        | fibrous wall; aids in refractive power of eye |  | 
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        | vascular wall; important blood supply of eyeball |  | 
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        | vascular wall; controls shape of lens |  | 
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        | vascular wall; controls pupil diameter |  | 
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        | part of the retina; blind spot; site where optic nerve leaves eye; lacks photoreceptors |  | 
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        | photoreceptor; vision receptors for dim light; more numerous; more sensitive to light; no color vision or sharp images; numbers greatest at periphery; contain single pigment; best suited for night vision |  | 
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        | photoreceptors; vision for bright light; high-resolution color vision; mascula lutea exactly at posterior pole; react more quickly; contain one of three pigments |  | 
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        | choroid supplied outer third; central artery and vein of retina supply the inner two thirds |  | Definition 
 
        | What are the two sources of blood supply to the retina? |  | 
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        | transmits light; supports posterior surface of lens; holds neural layer of retina firmly against pigmented layer; concontributes to intraocular pressure; forms in embryo |  | 
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        | composed of two chambers; anterior chmaber between cornea and iris and posterior chamber between iris and lens |  | 
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        | blocked drainage of aqueous humor increases pressure and causes compression of retina and optic nerve; leads to blindness |  | 
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 | Definition 
 
        | biconvex, transparent, flexible, and avascular; changes shape to precisely focus on retina |  | 
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        | bending of light rays; due to change in speed when light passes from one transparent medium to another; occurs when light meets surface of different medium at an oblique angle |  | 
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        | focusing for close vision |  | Definition 
 
        | requires eye to make adjustments; accommodation of lenses, constriction of pupils, and convergence of eyeballs |  | 
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        | for close vision; changing lens shape to increase refraction; near point of vision |  | 
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        | loss of accommodation over age 50 |  | 
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 | Definition 
 
        | for close vision; accommodation pupillary reflex constricts pupils to prevent most divergent light rays from entering eye |  | 
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        | for close vision; medial rotation of eyeball toward object being viewed |  | 
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        | problems of refractions; nearsightedness; focal point in front of retina i.e. eyeball too long; corrected with a concave lens |  | 
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        | problems of refractions; farsightedness; focal point behind retina i.ie. eyeball too short; corrected with convex lens |  | 
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        | problems of refractions; unequal curvatures in different parts of cornea or lens; corrected with cylindrically ground lenses or laser procedures |  | 
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        | light absorbing molecule that combines with one of four proteins to form visual pigments; synthesized from vitamin A |  | 
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 | Definition 
 
        | move from darkness into bright light; both rods and cones strongly stimulated; large amounts of pigments broken down producing a glare; improves over 5-10 minutes |  | 
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        | Term 
 | Definition 
 
        | move from bright into darkness; cones stop functioning in low intensity light; rod pigments bleached; system turned off; rhodopsin accumulates in dark; retinal sensitivity increases within 20-30 minutes; pupils dilate |  | 
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        | Term 
 | Definition 
 
        | results from cortical fusion of slightly different images; requires input from both eyes |  | 
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        | in roof of nasal cavity; cover superior nasal conchae; contains olfactory sensory neurons |  | 
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 | Definition 
 
        | gaseous odorant must dissolve in fluid of olfactory epithelium; dissolved oforants bind to receptor proteins in olfactory cilium membranes |  | 
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        | receptor organs on tongue |  | 
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        | 50-100 flask-shaped epithelial cells of 2 types |  | 
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        | gustatory epithelial cells |  | Definition 
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        | sweet, sour, salty, bitter, umami |  | Definition 
 
        | What are the five basic taste sensations? |  | 
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        | taste for amino acids glutamate and aspartate |  | 
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        | taste for alkaloids such as quinine and nicotine; aspirin (usually poisons) |  | 
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        | taste for hydrogen ions in solution (acid) |  | 
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        | taste for sugars, saccharin, alcohol, some amino acids, some lead salts |  | 
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        | Term 
 
        | Chemicals must be dissolved in saliva, diffuse into taste pore, and contact gustatory hairs |  | Definition 
 
        | What has to happen in order to taste? |  | 
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        | Term 
 
        | triggers reflexes involved in digestion; increase secretion of saliva into mouth; increase secretion of gastric juice into stomach; many initiate protective reactions (gagging, reflexive vomiting) |  | Definition 
 
        | What is the role of taste? |  | 
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        | external ear and middle ear |  | Definition 
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 | Definition 
 
        | used for hearing and equilibrium; receptors for hearing and balance respond to sparate stimuli; are activated independently |  | 
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        | anatomy of external ear; composed of helix (rim) and lobule (earlobe); funnels sound waves into auditory canal |  | 
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        | external acoustic meatus (auditory canal) |  | Definition 
 
        | anatomy of external ear; short, curved tube lined with skin bearing hairs, sebaceous glands, and ceruminous glands; transmits sound waves to eardrum |  | 
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        | Term 
 
        | tympanic membrane (eardrum) |  | Definition 
 
        | boundary between external and middle ears; connective tissue membrane that vibrates in response to sound; transfers sound energy to bones of middle ear |  | 
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        | middle ear (tympanic cavity) |  | Definition 
 
        | a small, air-filled, mucosa-lined cavity in temporal bone |  | 
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        | superior portion of middle ear |  | 
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        | pharyngotympanic (auditory) tube |  | Definition 
 
        | connects middle ear to nasopharynx |  | 
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        | thee small bones in tympanic cavity |  | Definition 
 
        | transmit vibratory motion of eardrum to oval window; tensor muscles contract reflexively in response to loud sound to prevent damage to hearing receptors |  | 
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        | middle ear inflammation; especially in children; most treated with antibiotics |  | 
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        | major division of internal ear; tortuous channels in temporal bone; three regions: vestibule, semicircular canals, and cochlea |  | 
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        | central egg-shaped cavity of bony labyrnith; contains two membranous sacs that house equilibrium receptor regions and respond to gravity and changes in position of head |  | 
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 | Definition 
 
        | one of the two membranous sacs of the vestibule that is continuous with cochlear duct |  | 
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        | one of the two membranous sacs of the vestibule that is continuous with semicircular canals |  | 
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        | three canls that each define 2/3 circle |  | 
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        | a spiral, conical, bony chamber about the size of split pea that extends from vestibule and coils around bony pillar; lined with three chambers |  | 
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        | perception of different frequencies |  | 
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        | most sounds mixtures of different frequencies |  | 
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        | equilibrium receptors in semicircular canals and vestibule |  | 
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        | sensory receptors for static equilibrium; monitor the position of head in space which is necessary for control of posture; respond to linear acceleration dorces but not rotation |  | 
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        | sensory receptor for rotational acceleration |  | 
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        | each crista has supporting cells and hair cells that extend into gel-like mass |  | 
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        | depolarizations and rapid impulses reach brain at faster rate |  | Definition 
 
        | What does bending of hairs in the cristae cause? |  | 
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        | hyperpolarization and fewer impulses reach the brain |  | Definition 
 
        | What does bending of hairs in opposite direction cause? |  | 
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        | Term 
 
        | changes in velocity of rotational movements of the head |  | Definition 
 
        | What does cristae respond to? |  | 
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        | Term 
 | Definition 
 
        | trange eye movements during and immediately after rotation; often accompanied by vertigo |  | 
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        | Term 
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        | sensory input mismatches; visual input differs from equilibrium input |  | 
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