sensory-system.pdf
TRANSCRIPT
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Sensory SystemsPrepared and presented by:
Prof. Paola Katherina M. Gonzales, MA
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AUDITIONAuditory System, anatomy and transduction
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The StimulusPitch
a perceptual dimension of sound;corresponds to the fundamental frequency
Hertz (Hz)
cycles per second
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The StimulusLoudness
a perceptual dimension of sound,corresponds to intensity
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The StimulusTimbre
a perceptual dimension of sound corresponding tocomplexity
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AnatomyTympanic membrane eardrum
Ossicle one of the three bones ofthe middle ear
Malleus the hammer; the first ofthe three ossicles
Incus the anvil; second to thethree ossicles
Stapes the stirrup; the last of thethree ossicles
Cochlea the snail-shaped structureof the inner ear that contains theauditory transducing mechanisms
Oval window an opening in thebone surrounding the cochlea thatreveals a membrane, against whichthe baseplate of the stapes presses,transmitting sound vibrations intothe fluid within the cochlea
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Organ of Corti the sensory organ onthe basilar membrane that containsthe auditory hair cells
Hair cell - the receptive cell of theauditory apparatus
Deiterss cell a supporting cell foundin the organ of corti which sustains theauditory hair cells
Basilar membrane a membrane inthe cochlea of the inner ear; containsthe organ of corti.
Tectorial membrane a membranelocated above the basilar membrane;serves as a shelf against which the ciliaof the auditory hair cells move.
Round window an opening in thebone surrounding the cochlea of theinner ear that permits vibrations to betransmitted via the oval window, intothe fluid in the cochlea.
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Auditory hair cells and the Transduction of Auditory information
Cilium a hairlikeappendage of a cellinvolved in movement or intransducing sensoryinformation found on thereceptors in the auditoryand vestibular system.
Tip link an elasticfilament that attaches thetip of one cilium to the sideof the adjacent cilium
Insertional plaque thepoint of attachment of atip link to a cilium
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Auditory Pathway: Connections with the cochlear nerve
Cochlear nerve the branch of the auditory nerve that transmits auditory information from the cochlea to the brain
Olivocochlear bundle a bundle of efferent axons that travel from the olivarycomplex of the medulla to the auditory hair cells on the cochlea.
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Central Auditory System Cochlear nucleus
one of a group of nuclei inthe medulla that receive auditoryinformation from the cochlea
Superior Olivary Complex
a group of nuclei in themedulla involved with auditoryfunctions, including localization ofthe source of sounds
Lateral lemniscus
a band of fibers runningrostrally through the medulla andpons which carries fibers of theauditory system.
Tonotopic representation
a topographicallyorganized mapping of differentfrequencies of sound that arerepresented in a particular region ofthe brain
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Central Auditory System
Core region the primary auditory cortex, located on a gyrus on the dorsalsurface of the temporal lobe
Belt region the first level of auditory association cortex surrounds theprimary auditory cortex.
Parabelt region the second level of auditory association cortex surrounds thebelt region.
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Perception of Pitch
Place coding
the system by whichinformation about differentfrequencies is coded by differentlocations on the basilar membrane.
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Perception of Pitch
Cochlear implant
an electronic devicesurgically implanted in the inner earthat can enable a deaf person tohear.
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Perception of PitchRate coding
the system by whichinformation about differentfrequencies is coded by the rate offiring of neurons in the auditorysystem.
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Perception of Loudness
Most investigators believe that the loudness of low frequencysounds is signaled by the number of axons arising from theseneurons that are active at a given time.
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Perception of TimbreFundamental frequency
the lowest, and usually most intense frequency of a complex sound and most often perceived as the sounds basic pitch.
Overtone
the frequency of complex tones that occurs at the multiples of the fundamental frequency.
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Localization by means of arrival time and phase difference
Phase difference
the difference in arrival times of sound waves at each of the eardrums
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Amusia
loss or impairment of musical abilities, produced by hereditary factors or brain damage.
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VESTIBULAR SYSTEM
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Vestibular System
Vestibular Sac
one of a set of tworeceptor organs in eachinner ear that detectchanges in the tilt of thehead.
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Anatomy of the Vestibular Apparatus
Semicircular canal
one of the three ringlikestructures of the vestibular apparatusthat detect changes in head rotation
Utricle
one of the vestibular sacs
Saccule
one of the vestibular sacs
Ampulla
an enlargement in asemicircular canal that contains thecupula and the crista
Cupula
a gelatinous mass found inthe ampulla of the semicircular canalsthat moves in responses to the flowof the fluid in the canals.
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Anatomy of the Vestibular Apparatus
Vestibular ganglion
a nodule on the vestibular nerve thatcontains the cell bodies of the bipolar neuronsthat convey vestibular information to thebrain.
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SOMATOSENSES
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One of the somatosenses that includes sensitivity to stimuli involving the skin.
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ProprioceptionPerception of the bodys position and posture
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Perception of the bodys own movement
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Organic Sense
A sense modality that arises from receptors located within the inner organs of the body
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Anatomy of the SKINGlabrous Skin skin that does not contain hair, found onthe palms and soles of the feet.
Merkels disk - a touch sensitive cutaneous receptor, important for detection of form and roughness, especially by fingertipsRuffini Copuscle a touch sensitive cutaneous receptor, important in detecting stretching or static force against the skin, important in proprioception.
Meissners Corpuscle a touch sensitive cutaneousreceptor important in detecting edge contours or Braille like stimuli, especially by fingertips.
Pacinian Corpuscle a vibration sensitive cutaneousreceptor, important in detecting vibration from an objectbeing held
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Perception of Cutaneous Stimulation
Mechanoreceptor
a sensory neuron that responds to mechanical stimuli; forexample, those that produce pressure, stretch, or vibration of theskin or stretch of muscles or tendons.
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Temperature Pain
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Itch
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Somatosensory Pathway
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Somatosensory Pathway
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Tactile Agnosia
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Tactile ApraxiaDifficulty in carrying out purposeful movements in the absence of paralysis or muscular weakness
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Phantom Limb
Sensation that appear to originate in a limb that has been amputated.
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Nucleus Raphe Magnus
A nucleus of the raphe that contains serotonin secreting neurons that project to the dorsal gray matter of the spinal cord and is involved in analgesia produced by opiates.
(ex. Opiate induced analgesia)
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GUSTATION
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UmamiThe taste sensation produced by monosodium glutamate (amino acids found in proteins).
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The tongue
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Anatomy of the taste buds and Gustatory Cells
Papillae
small protuberances of the tongue
Fungiform papillae
located on the anterior two thirds of the tongue, contains up to eighttaste buds, along with the receptors ofpressure, touch and temperature.
Foliate papillae
consists up to eight parallel foldsalong each edge of the back of the tongue(approx. 1,300 taste buds)
Circumvallate papillae
arranged in an inverted V on theposterior third of the tongue (approx.250taste buds)
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The structure of taste receptor
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Gustatory pathway
Chorda Tympani a branch of facialnerve that passes beneath theeardrum; conveys taste informationfrom the anterior part of thetongue and controls the secretionof some salivary glands.
Nucleus of the solitary tract -nucleus of the medulla thatreceives information from visceralorgans and from the gustatorysystem.
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OLFACTION
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Stimulus
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Anatomy of the olfactory Olfactory epithelium theepithelial tissues of the nasalsinus that covers the cribriformplate; contains the cilia of theolfactory receptors
Olfactory bulb the protrusion atthe end of the olfactory tractwhich receives input from theolfactory receptors.
Mitral cell a neuron located inthe olfactory bulb that receivesinformation from olfactoryreceptors; axons of mitral cellsbring information to the rest ofthe brain.
Olfactory glomerulus a bundleof dendrites of mitral cells and theassociated terminal buttons of theaxons of olfactory receptors
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Transduction of Olfactory Information