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Sensation (Sensory Transduction)

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For many, the sense of hearing is thesecond most important sense

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Bending of cilia causes changes inreceptor potentials

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General pathway of audition

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Perception of pitch

he cochlea detects frequency by coding

llows for tonotopic organization

Cochlear implants

high frequency low frequency

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Perception of timbreixture of frequencies

xample: music

oded in basilar membrane and ultimately identied in the auditory cor

Perception of loudnessCochlea is an extremely sensitive

ouder sounds produce more intense vibrations of the eardrumand ossicles

which produce a more intense shearing force on the cilia of theauditory hair cells

Perception of spatial locationare most accurate in "udging sound localization with respect to the azi

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Deafness

Conduction deafness # external or middle ear is defective

$ensorineural deafness # inner ear is defective

Central deafness # auditory pathway in brain is defective

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The cochlear and estibular neresconstitute the two branches of !" #$$$

prioceptive imbalance

tibular system also connect to the cranial nerves that control eye mus' &()

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!hemical senses allow for chemicalinteractions with speciali%ed receptors

gustation

olfaction

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Gustation

!ithin taste buds are groups of *+',+ receptor cells

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General pathway of gustation

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& 'ualities of taste

-. /itterness # associated with toxic substances

*. $ourness ' responds to hydrogen atoms in acidic solutions

0. $weetness

1. $altiness # substance must ionize

,. 2nami # recently discovered detects presence of glutamate

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lfaction

(dorous molecules dissolve in the mucus and stimulate specialized

receptors in the cilia

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ithin the olfactory bulb is the glomerulus

Each glomerulus receives information from only

one type of olfactory receptor

This coding is maintained all the way up to the

olfactory cortex

Coding is recognition of patterns

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Somatosenses

%ressure3 vibration3 heating3 cooling3 pain

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The s*in

Epidermis

4ermis

5ypodermis

uch is detected by specialized touch receptors 67er8el9s3 7eissner9s3 )uni9s3 %

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+eceptie eld

time

= ofspi8es

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- neuron in &-

"eurons in #- hae preferredorientations and we can assess

these orientations by studying thereceptie eld properties of the

neurons