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Unformatted text preview: 04/03/2008 10:04:00 Types of Receptors Mechanoreceptors touch, pressure, hearing Thermoreceptors temperature Photoreceptors light (vision) Chemoreceptors activated by chemicals for smell and taste Pain Receptors physical or chemical trauma to tissue Referred Pain feeling pain of internal organs in distant location (nerves combine at spinal cord) The Eye Photoreceptors change light to chemical signal transmitted to the brain Light goes from the lens to the retina (photoreceptors); the lens focuses light on the retina; the retina transforms the light to a chemical signals Fovea a high concentration of photoreceptors, which allows us to see details Optic Nerve transfers chemical signal to occipital lobe Vitreous humor behind the lens in front of the retina (never replaced) Aqueous humor in front of lens replaced constantly; nourishment (is replaced) The Ear Pinna outer ear; funnel sound into auditory canal Eardrum tympanic membrane; vibrates in response to sound Malleus } Incus } vibrate (amplify vibrations) Stapes } Cochlea vibrated by ear bones through the oval window o Hair cells move to activate sensory neurons Vestibular Apparatus correct head position relative to the rest of the body Special Senses Smell Vision Hearing General Senses Touch Pressure Internal Senses Eye Disorders Glaucoma drainage of aqueous humor blocked (increase of fluid = an increase in pressure) Cataracts cloudiness of the lens; light cannot penetrate Macular Degeneration decrease in photoreceptors (in fovea) results in a progressive loss of vision (can tell there is a face, but cannot point out certain features [nose, mouth, eyes, etc.]) Nearsightedness loss of vision far away (light is focused in front of retina) Farsightedness loss of vision close to you (light is focused behind retina) Ear Disorders Conductive Hearing Loss blockage in sound movement...
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This note was uploaded on 04/07/2008 for the course HIST 101 taught by Professor Mcvety during the Spring '08 term at Miami University.
- Spring '08