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Unformatted text preview: r field Lateral inhibition- several receptors respond to a stimulus, while others do not. • Lateral inhibition increases contrast between responsive vs unstimulated receptors. • • • • • • • • • • • • Some body regions have greater representation. More cortex devoted to processing stimuli from that region. Ear External ear- consists of pinna, external auditory meatus, and tympanum. Transmits airborne sound waves of fluid-filled inner ear. Amplifies sound energy. Middle ear Transmits airborne sound waves to fluid-filled inner ear. Amplifies sound energy. Inner ear Houses two different sensory systems. Cochlea- contains receptors for conversion of sound waves into nerve impulses which makes hearing possible. • Vestibular apparatus- contains receptors for conversion of acceleration into nerve impulses which is important for service of equilibrium. • • • • • Auditory system Neural perception of sound energy. Identification of sound and localization of sound Sound waves- traveling vibrations of air Consist of alternate regions of compression and refraction of air molecules. • Broken down to frequency and amplitude components by the receptors in the inner ear. • Information is processed in the brain by resynthesizing the frequency an amplitude components conveyed by the receptor generated APs. • • Tympanic membrane vibrates when struck by sound waves Middle ear transfers vibrations through ossicles to oval window (enterance into fluid filled cochlea). • • • Pressure waves in cochlear fluid set basilar membrane in motion. Receptive hair cells are bent as basilar membrane is deflected up and down. Mechanical deformation of specific hair cells is transduced into neural signals that are transmitted to auditory cortex in temporal cortex in temporal lobe of brain for sound perception. • • • • • • • • Vestibular- equilibrium Vestibular apparatus and receptors In inner ear. Consists of 2 classes of receptors Semicircular ca...
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- Spring '10