Lecture_10

Lecture_10 - Lecture 10 •  SmartSite: – ...

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Unformatted text preview: Lecture 10 •  SmartSite: –  Lecture 10 Notes •  Review –  Sensory Systems –  The Ear •  Announcements: –  None •  Reading (Recommended): –  Relevant por<ons of Chapter 6 •  Auditory system •  Ves<bular system REV: Sensory Integra<on 1.  Modality or type of sensory informa<on 2.  Receptor type 3.  AP firing rate of afferent propor<onal to s<mulus intensity 4.  Rate of receptor adapta<on 5.  Number of afferents firing 6.  Receptor density / Receptor field size 7.  Lateral inhibi<on 8.  Labeled line coding REV: Ear  ­ Auditory •  Tympanic membrane vibrates when struck by sound waves •  Middle ear transfers vibra<ons through ossicles to oval window •  Pressure waves in cochlear fluid set basilar membrane in mo<on •  Recep<ve hair cells are bent as basilar membrane is deflected up and down •  Mechanical deforma<on of specific hair cells is transduced into afferent neural signals •  APs are transmiXed to auditory cortex in temporal lobe of brain for sound percep<on Fig. 6 ­32, pg. 215 REV: Transmission of Sound Waves Fig. 6 ­36bc, pg. 219 Sound Transduc<on hXp://www.rockefeller.edu/labheads/hudspeth/graphicalSimula<ons.php Cochlea Fig. 6 ­35ab, pg. 218 Auditory Receptors Fig. 6 ­357 pg. 220 Hair Cells Fig. 6 ­40, pg. 223; Fig 6 ­38c, pg 221 Sound Transduc<on Fig. 6 ­39, pg. 222 Ear  ­ Ves<bular Fig. 6 ­32, pg. 215 Ves<bular  ­ Equilibrium •  Ves<bular apparatus and receptors –  In inner ear –  Consists of 2 classes of receptors •  Semicircular canals (3 orthogonally ­oriented canals per side) –  Detect rota<onal accelera<on or decelera<on in any direc<on •  Otolith organs (2 Macular receptors at right angles per side: utricle and saccule) –  Detect linear accelera<on »  Detect changes in rate of linear movement in any direc<on »  Provide informa<on important for determining head posi<on in rela<on to gravity Equilibrium •  Neural signals generated in response to mechanical deforma<on of hair cells by specific movement of fluid and related structures •  Ves<bular input goes to ves<bular nuclei in brain stem and to cerebellum for use in maintaining balance and posture, controlling eye movement, perceiving mo<on and orienta<on Ves<bule Fig. 6 ­41a, pg. 225 Semicircular Canals •  Hair cell bundles are aligned in mirrored orienta<on •  Rota<on depolarizes one set of hair cells and hyperpolarizes the hair cells in the opposite semicircular canal Fig. 6 ­41c, pg. 225 Semicircular Canals Fig. 6 ­41c, pg. 225 Hair Cell Receptors • The response is similar to that in auditory hair cells • Stereocilia bending toward the kinocilium: Depolariza<on • Stereocilia bending away from the kinocilium: Hyperpolariza<on Fig. 6 ­41d, pg. 225 Otolith Organs (macular receptors) Fig. 6 ­42a, pg. 226 Linear Accelera<on Fig. 6 ­40bc, pg. 221 Ves<bular Input ­Output Rela<ons Fig. 6 ­43, pg. 227 ...
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This note was uploaded on 02/10/2010 for the course BIO NPB taught by Professor Furlow during the Spring '10 term at UC Davis.

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