Senses.pptx

8/21/2019 Senses.pptx

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Senses1

HUMAN E YE = SENSE OF SIGH


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Senses2

HUMAN E YE The eye helps the human to recognize the worldaround us. With the help of eyes, we can distinguish

between night and day, near and far and a lot ofthings which adapt the human to the environment.Without sense of sight, the life would be boring.The eyes contain the receptors for liht calle!

photoreceptors"Eye is the light-sensitive organ of vision in animals.The eyes of all #erte$rate oranis%s arestr&ct&rally si%ilar to each other an!rese%$le a si%ple ca%era in f&nction"A #erte$rate eye consists of t'o %ainstr&ct&res(

-an eye sphere-accessory structures


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Senses)

Str&ct&re of Eye Sphere-Eye sphere consists of the followingcomponents:

sclera

choroi!

retina


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Senses*

ScleraIt is the o&ter%ost layer an! the 'hite part ofthe eye" Its f&nction is to protect the eye fro%

e+ternal e,ects"At the front of the sclera, the sclera becomes thin,transparent and slightly curved. This part is calledcornea" clera protrudes to outside and formscornea. !f the cornea is infected with any damage,less amount of light enters the eye and the vision isa"ected# because liht enters the eye thro&hthe cornea"

The e$ternal cover %membrane& of sclera is called

-on.&ncti#a which 'eeps the eye moist.


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Senses/

-horoi!-(horoid is located )ust inside the sclera.-It contains %any $loo! #essels 'hich no&rish

the eye" At the front of the eye0 $ehin! thecornea0 the choroi! for%s the iris" -!n the iris,there are pigments that give color to the eye andthere is a small hole in the centre of the iris# thishole is called p&pil.-The p&pil allo's liht to pass to inner partsof the eye"


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Senses

control and regulate the amount of light that entersthe eye by changing the size of the pupil.hen the liht is $riht0 the circ&lar s%ooth

%&scles contract an! the p&pil ets s%aller0so less liht enters the eye" Other'ise0 the$riht liht can !a%ae the eye"When the light is dim, the radial smooth musclescontract and the pupil gets larger, so more lightenters the eye.

The size of pupils is automatically controlled bycentral nervous system. If the eye is tho&ht to $e a

ca%era0 iris 'o&l! $e the

!iaphra% of it"

Diaphragm


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-*ehind the iris, there is astructure that is elastic,transparent and biconve$.This str&ct&re is calle!

lens"Its f&nction is to foc&sinco%in liht rays onto the retina"The lens con#e+ity is

chane! $y the actionof special %&sclesattache! to the lens"-!n the front of the eye,choroid forms a muscle

tissue composed of smoothmuscles.-This %&sc&lar str&ct&reis calle! ciliary $o!yan! it is connecte! 'ithlens0 an! it isresponsi$le for

(iliarybody


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5etina-!t is the innermost layer of the eye and contains thephotoreceptor cells that capture light energy.

6At the rear of the eye0 the retina is attache!to the optic ner#e 'hich carries i%p&lses fro%the liht sensiti#e cells to the $rain.-The retina contains of two types of photoreceptors:rods and cones which convert light energy toelectrical signals that can be interpreted by thebrain.


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+ods % million& respond best to dim light andenable white and blac' vision %night vision&.-ones 83 %illion9 respon! $est to $riht lihtan! ena$le color #ision"

The retina also contains many other neurons %opticnerves& that process visual information.

/FO:EA; The area ofretina in which the

sharpest image isformed and color ispossible. 0ight sensitivecells %(12E& are mostlylocated in fovea.IN? S@OT ; Thereare no rod or cone cellswhere the optic nerve

passes through theretina at the bac' of theeye. This part is calledblind spot and vision isimpossible in blind spot.


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a9 Anterior cha%$er 8=$et'een cornea an! iris9$9 @osterior cha%$er 8=$et'een iris an! lens9c9 :itreo&s cha%$er 8=entire space $ehin! the

lens9 Anterior and posterior chambers are 4lled with aB&eo&s

h&%o&r %5a special 6uid&. 7itreous chamber is the largestcavity of the eye sphere. !t is 4lled with #itreo&s h&%o&r"

*oth a8ueous humour and vitreous humour are produced byciliary body and both are responsible for maintaining the innerpressure of the eye sphere.

The lens0 the aB&eo&s h&%or0 an! the #itreo&s h&%orall play a role in foc&sin liht onto the retina"

l f h


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The protection of the eye is provided by some structures.& 1rbit of the s'ull %5eye soc'et&& Eyelid

3& Eyelashes9& Eyebrows& (on)unctiva& Apparatus;&


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lacri%al sac0 lacri%al !&ct an! nasolacri%al !&ct.0acrimal gland secretes 6uids every time not only duringcrying. 0acrimal gland secretes tears# provides the eye spherewith moisture. Tears are composed of salt, water, lysosomeand other organic compounds.

After secretion thro&h lacri%al !&cts0 the C&i! isrelease! on the cornea to clean an! %oisten it" E+cessC&i! is collecte! $y lacri%al sac an! release! into thenasal ca#ity thro&h nasolacri%al !&ct"

39 M&scles( They help the organism to move eyeballs toevery direction for a good sight. i$ sets of muscles serve forthis aim. !f there is a defect in their structure this results indouble vision. The movement of these muscles is regulated by

cranial nerves


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:is&al @rocess=HO ?O E SE>iht enterin the eye passes thro&h the cornea0p&pil an! lens that foc&ses liht on the retina"

Then, an image is formed on the retina. 0ight waves areconverted to nerve impulses by neurochemical activity %5inthe photoreceptors&.After that0 i%ae 8i%p&lse9 is carrie! $y optic ner#efro% the liht sensiti#e cells on retina to the $rain"

The impulses are processed at

the brain, the inverted imageis corrected and theinformation is interpreted.The i%ae for%e! on theretina is in#erte!0 an! it istho&ht that perhaps this

i%ae is rihte! in the$rain $y e+perience"

The eyes and the brainwor'ing together allow us tosee the ob)ects right side up

and in three dimensions.


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acco%%o!ation %etho!s;

Metho! 1( y &sin elastic lens!n this type of eye, the lens is elastic and it may change its

shape %5may 6atten or enlarge& by the help of the musclesaround it. 2ormally, the eye is accommodated to see far awayob)ects.

In this for%0 the lens is enlare!" The %&scles aro&n!the eye contracts an! the lens Cattens" The liht is notrefracte! too %&ch0 res&ltin in the for%ation of thei%ae on the retina"

!n order to view close ob)ects, the lens becomes smaller. Themuscles around the lens rela$es and the lens enlarge, the lightis refracted more this results in the formation the image on theretina. =isorders in muscles create disorders in vision. This sortof eye is present in mammals and human.

Metho! 2( y &sin rii! lensA rii! lens cannot chane its shape; instea!0 itslocation is chane!" Nor%ally0 the eye is acco%%o!ate!to see close o$.ects" In this for%0 the lens is far fro% theretina" In or!er to #ie' far a'ay o$.ects0 the lens is

p&lle! close to the retina $y %&sc&lar acti#ity" This in!of eye is present in sh"


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UMAN EA5 = SENSE OF HEA5I

The human ear has two sensory functions:1" Hearin2" Maintanin $alance or eB&ili$ri&%

Ear is consi!ere! as the one of co%ple+ sense orans"Ear contains t'o in!s of receptors; the rst type is

specialie! to recei#e the so&n! an! the secon! type isspecialie! to !eter%ine the $o!y position an!$alance"


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he Str&ct&re of the Ears>uman ear contains three main parts: O&ter ear

Mi!!le ear Inner ear


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O t


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O&ter ear1uter ear is composed of 3 parts:@INNA is a cartilaginous tissuewhich collects sound waves and

determines their source.AU?ITA5Y -ANA> is a canalwhich is found between pinna andeardrum. !t has hairs and produceswa$-li'e substance to 4lter solid

particles.THE EA5?5UM is a thin half-transparent membrane whichseparates the outer ear from themiddle ear. ?or hearing, theeardrum must vibrate. Ear!r&% isconnecte! to an ossicle 8=s%all$one9 of %i!!le ear na%e! as%alle&s 8=ha%%er9"

2ormal Eardrum+uptured Eardrum


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Mi!!le ear-!t contains 3 small bones which are called the hammer, anviland stirrup6These $ones for% a chain across the %i!!le ear linin

the ear!r&% to another %e%$rane0 the o#al'in!o'"-The hammer is attached to the eardrum, the anvil connectsthe hammer to the stirrup and strirrup is connected to the ovalwindow

>ammerAnvil

tirrup


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EUSTA-HIAN TUE The function of Eustachian tube is to e8ualize the air pressureon both sides of eardrum.E&stachian t&$e is a connection $et'een the %i!!leear an! the pharyn+" E&stachian t&$e is close! 'ith a

#al#e on the pharyn+ si!e to pre#ent any passae init"When the e$ternal pressure changes %e$: pressure change

while we climb a hill& any opening of the valve permits the airpassage into the middle ear, thus, this balances e$ternal and

internal pressures. *alance of the pressures is important inprotecting the eardrum from rupturing.

I


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Inner ear- The inner ear is involved hearing and maintaining the balanceof the body.-The orans of hearin an! $alance are 'ell protecte!

$y the $ony str&ct&res"-!nner ear consists of the cochlea and semicirsular canals.-The oran for hearin is cochlea an! the orans for$alance are se%icirc&lar channels an! #esti$&l&%"-7estibulum is made up of two sacs. These sacs are utriculus

and sacculus.

-ochlea( !t is a spiral coil structure %li'e snail& that consists of


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Senses22

-ochlea( !t is a spiral coil structure %li'e snail& that consists ofa bony part called $asilar $one and some membranestructures called $asil %e%$ranes.-ochlea consists of ) C&i! lle! canals separate! $y

%e%$ranes" These canals are #esti$&lar canal0

cochlear canal an! ty%panic canal 8=in #esti$&larcanal an! in ty%panic canal perily%ph0 in cochlearcanal en!oly%ph is present9"

@erilymph transfers the sound from oval window into the


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Senses2)

@erilymph transfers the sound from oval window into theendolymph which 4lls the basil membrane cavity. Theendolymph transfers the vibration into the receptor cells.When these cells are stimulated, they send nervousimpulses by auditory nerve into hearing centre in the

cerebrum.:esti$&lar canal is in contact 'ith the o#al 'in!o'

'here ty%panic canal is in contact 'ith ro&n!'in!o'"

1val window and round window are membranes located

between inner and middle ear.O#al 'in!o' is attache! to stirr&p 'here ro&n!

'in!o' is free" -ochlear canal is in contact 'ithsacc&l&s"

Oran of -orti is the main organ in cochlea for hearing The


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Senses2*

Oran of -orti is the main organ in cochlea for hearing. Theorgan is located on the membrane separating the cochlearcanal and the tympanic canal. There are appro+i%ately 26* tho&san!s of %echanoreceptors calle! hair cells0'ith !i,erent lenths0 attache! to the oran of -orti"

Any #i$ration in the en!oly%ph of cochlear canal issense! $y the oran of -orti"


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Senses2/

hair cell in organ of corti

These a$ons form the auditory

nerve

H i Th h i f h


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Senses2

Hearin-ound waves collected by outer ear pass down the auditorycanal to the eardrum.6They ca&se the ear!r&% to #i$rate" ehin! theear!r&%0 three s%all $ones of the %i!!le ear; theha%%er0 an#il an! stirr&p transfer the #i$rations too#al 'in!o'"-The oval window transmits the vibrations to the perilymph inthe vestibular canal. The vibration travels the length of the

vestibular canal, around the far end of the cochlea, and bac'through the tympanic canal to the round window membrane.6As the #i$rations tra#el thro&h the #esti$&lar canalan! ty%panic canal0 they set &p #i$rations in theen!oly%ph of the cochlear canal" These #i$rations

#i$rate the hairs in the oran of -orti"-7ibrations are converted into chemoelectrical impulses in thesensory neurons of the organ of (orti and are transmitted tothe brain for processing.6The ner#e that carries the i%p&lses fro% the ear to

the $rain is na%e! as a&!itory ner#e" 8=aco&sticner#e9"

The %echanis% of hear

Hearin


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Senses23

Hearin

i Y l


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Senses24

eepin Yo&r alanceSe%icirc&lar -anals( The semicircular canals consist ofthree tubes located in three vertical planes. Each canal loo'sli'e an arched tube.These canals contain C&i! an! hair lie pro.ections that!etect chanes in $o!y position" Se%icirc&lar canals%onitor the position of the hea! an! %aintaineB&ili$ri&%" The cha%$ers of these canals are lle!'ith ly%phatic C&i! 8en!oly%ph9"

The function of semicircular canals is to send re8uired

information about the body position to the cerebellum, so thebody ta'es a proper action to maintain its balance.


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Senses27

In se%icirc&lar canals0 there are t'o s%all %e%$rano&ssacs calle! the otolith orans 'hich are the &tricle an!sacc&le are locate!" In &tric&l&s an! sacc&l&sen!oly%ph is present"

They sense gravity and linear movement such as initiation ofmovement in a straight line. @ersons or animals without otolithorgans are imbalanced.Hair cells are fo&n! in these orans to !etect an! a!.&stthe $o!y position"

!n utriculus and sacculus nerve cells form some patches


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Senses)

!n utriculus and sacculus, nerve cells form some patches. These patches are named as maculae %mm in diameter&. !nthe maculae, (a(13 %5(alcium carbonate& crystals are

present. These crystals are 'nown as ear stones or otoliths.A chane in $o!y position ca&ses the otoliths to %o#e"After that0 otoliths sti%&late the hair cells 'hich sen!i%p&lses to the $rain a$o&t $o!y position"

semicircular canals which is 4lled by endolymph. Their function


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Senses)1

semicircular canals which is 4lled by endolymph. Their functionis to monitor the position of the head and maintain e8uilibrium.In the a%p&lla of each se%icirc&lar canal0 so%e patchesna%e! as crista statica are present" Each crista staticacontains ciliate! sensory cells" The cilia are locate! in a

elatin lle! sac na%e! as c&p&la"When the head moves, the endolymph in the canals movesand so the cupula moves. The movement of cupula generatesimpulses in ciliated sensory cells. 0ater, the impulses aretransmitted to brain.


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Senses)2


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Senses)) SIN=SENSE OF TOU-H


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Senses)*

-All multicellular organisms have s'in composed ofone or more layers.-The sense of touch is located in the s'in.-The nerve in the s'in allow us to feel te$ture,pressure, heat, cold and pain.

SIN=SENSE OF TOU-H


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Senses)/

& @rotection of the inner layers of the body from

physical and chemical e"ects& @revention of the entry of the microbes

3& @revention of water loss in terrestrial organisms9& @rotection of the cells from 7 light or intense

light& +egulation of body temperature

&


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Senses)

'in is completely composed of twodi"erent layers

19Epi!er%is

29?er%is

E i! i


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Senses)3The keratinized layer is the superficial layer of dead squamous cells.

Epi!er%i

s

-!t is the outermost layer of s'in.6This layer is co%pose! of

eratinise! epithelical cells"6Upper section of epi!er%is isco%pose! of non6li#in cells"-The epidermis is replaced with anew one as it sheds.

!t is a barrier against chemical and physical e"ects and it


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Senses)4

g p yalso prevents the entry of microbes. !t originates fromectoderm in the embryo.

!t does not contain any blood vessels and nerve cells.


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Senses)7

Melanocytes are cells located inthe bottom layer of the s'inFsepidermis and they produce%elanin which is a pigmentwhich gives the color of the s'in.

%elanocytes

?er%


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Senses*

nder epidermis layer, there is dermis layer. !t isappro$imately times thic'er than the epidermis.

It oriinates fro% the %eso!er% of thee%$ryo"

The dermis contains & *lood vessels& 2erve

endings

3& ebaceousglands

9& weat glands& >air follicles& 0ymph

vessels;& mooth

musclesB& +eceptors

?er%is


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Senses*1

16 loo! #essels nourish thes'in and remove the wastematerials

26 Ner#e en!ins are for thereception of stimuli

)6Se$aceo&s lan!s secrete a

substance that protects the bodyagainst infectious bacteria andfungi. They are scattered throughthe s'in and present in all areas

of the body e$cept the palms and

l ! i ll


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Senses*2

*6 S'eat lan!s are present in allregions of the s'in. They are openonto the surface of s'in by pores.

They are involved in removal of water,

minerals, urea and other substances. The main function of sweat glands isto regulate body temperature byevaporation of water.

/6 Hair follicle is the invisible portionof a hair, in the dermis. The visibleportion is named as hair shaft. >airfollicle is in contact with smoothmuscles, blood vessels, nerve endingsand sebaceous glands.The color of the hair is i#en $ythe pi%ent %elanin" In $lon!s0%elanin is less pro!&ce!" Inal$inos0 there is no %elaninpro!&ction !&e to their enetic

str&ct&re" ?&rin ain hairs


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Senses*)

6 >y%ph #essels carry thelymph 6uid all about thedermis and function in

immunity.

36 S%ooth %&scles providethe movement of the hair. %in

human and cats&

6 ecep ors o e s n are presen n e erm s.Th t h t d


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Senses**

p p These receptors are mechanoreceptors andfunctional in the reception of touch, pressure,temperature and pain.5eceptors are !i#i!e! into t'o types;

-212(A@0ATE= +E(E@T1+:a&


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Senses*/ 16NON-A@SU>ATE? 5E-E@TO5S(


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Senses*

a9 MerelJs corp&scles;


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Senses*3

ypain reception. When a section in the body isin)ured, the individual feels pain and tries toremove the pain by an action.

!9 Hair follicle receptors are present around the


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Senses*4

!9 Hair follicle receptors are present around thehair follicle and they are related to sense of touch.

26-A@SU>ATE? 5E-E@TO5S(


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Senses*7

a9 @acinian corp&scles are the most importantreceptors of the s'in. They are the greatestmechanoreceptors in the s'in. They are located in

the walls of inner organs and are responsible for thedetection of heavy pressure changes.

mechanoreceptor and a type of nerve endings in


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Senses/

the s'in that are responsible for sensitivity to lighttouch. They are !istri$&te! thro&ho&t the sin0 $&t

concentrate! in areas especially sensiti#e toliht to&ch0 s&ch as the nertips0 pal%s0soles0 lips0 ton&e an! face"


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Senses/1

p ptemperature changes.ra&se corp&scles are in#ol#e! in thereception of col! an! 5&Kni corp&scles are

in#ol#e! in the reception of heat"

NOSE=SENSE OF


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Senses/2

-2ose is the organ of the body involved inrespiration and detection of di"erent types of

smells.6Yo&r nose lets yo& s%ell an! itLs a $i part of'hy yo& are a$le to taste thins" The nose isalso the %ain ate to the respiratory syste%0

yo&r $o!yLs syste% for $reathin"

NOSE=SENSE OFSME>>

Nose @artsTh h t h l ll d t il Th t il d th


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Senses/)

The nose has two holes called nostrils. The nostrils and thenasal passages are separated by a wall called the septum.=eep inside your nose, close to your s'ull, your septum ismade of very thin pieces of bone.

-loser to the tip of yo&r nose0 the sept&% is %a!e ofcartilae0 'hich is Ce+i$le %aterial thatLs r%er thansin or %&scle" ItLs not as har! as $one0 an! if yo& p&shon the tip of yo&r nose0 yo& can feel ho' 'ily it is"*ehind your nose, in the middle of your face, is a space called

the nasal cavity. !t connects with the bac' of the throat.

The insi!e of yo&r nose is line! 'ith a %oist0 thin layer oftiss&e calle! a %&co&s %e%$rane This %e%$rane 'ar%s &p


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Senses/*

tiss&e calle! a %&co&s %e%$rane" This %e%$rane 'ar%s &pthe air an! %oistens it" The %&co&s %e%$rane %aes %&c&s0that sticy st&, in yo&r nose"


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Senses//

1lfactory is a fancy word that has to do with smelling. Theolfactory epithelium contains special receptors calledche%oreceptors that are sensitive to odor molecules thattravel through the air.

These receptors are #ery s%all there are at least 1%illion of the% in yo&r nose There are h&n!re!s of!i,erent o!or receptors0 each 'ith the a$ility to sensecertain o!or %olec&les" The $rain interprets theco%$ination of receptors to reconie any one of a$o&t

10 !i,erent s%ells"


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Senses/ ?ETE-TION OF SME>>


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Senses/3

For the !etection of s%ell0 the %olec&les fro% the air%&st rst !issol#e in the nasal %&cosa" >ater0 the%olec&les sti%&late $y the ciliary part8=che%oreceptors9 of the olfactory ne&rons"

When the smell receptors are stimulated, signals travel alongthe olfactory nerve to the olfactory bulb. The olfactory bulb isunderneath the front of your brain )ust above the nasal cavity.Sinals are sent fro% the olfactory $&l$ to other partsof the $rain to $e interprete! as a s%ell yo& %ay

reconie"


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Senses/4 Yo&r sense of s%ell also can help yo& eep safe" Fore+a%ple it can 'arn yo& not to eat so%ethin that


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Senses/7

e+a%ple0 it can 'arn yo& not to eat so%ethin thats%ells rotten or help yo& !etect s%oe $efore yo& seea re"


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Senses

nutrition.

The capacity of s%ellin is !i,erent in !i,erent ani%als;Sense of s%ellin in terrestrial ani%als is %ore!e#elope! than that of aB&atic ani%als"

1lfactory neurons are easily paralyzed.As we smell something for a long time


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Senses1

As we smell something for a long timeits smell is lost after sometime.This characteristic of olfactory

ne&rons is a little ins&rance aainst$a! scents"

Did you know?•Dogs have 1 million smell cells per nostril, and their cells

are up to 100 times larger than those of humans.•Anosmia is the condition that makes people unableto smell.•Your sense of smell directly affects your sense of taste.•Smell can evoke emotions such as happiness, fear,even sexuality. the "smell-brain," the hinocephlonis functionally associated with the entire emotionaltone of a person.

TONGUE=SENSE OF


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Senses2

TONGUE=SENSE OFTASTE

The tongue is a muscle on the 6oor of the mouththat chew and swallow food. !t is the primary organ

of taste.A secondary function of the tongue is speech. !t is

sensitive and 'ept moist by saliva, and is richlysupplied with nerves and blood vessels to help it

move.

Yo& nee! yo&r ton&e to che'0 s'allo'0 an! sin" An!!onLt foret talin an! tastin

F&nctions of ton&e in n&trition0 speech an!


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Senses)

in !etection of !i,erent tastes"

Taste !etection

SpeechN&trition

The surface of the tongue or the epithelial layer of the tongue iscovered with small pro)ections called papillae. There are the taste


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Senses*

covered with small pro)ections called papillae. There are the tastereceptors or taste $&!s within the papillae. @eople are $orn 'itha$o&t 10 taste $&!s" &t as a person aes0 so%e of his orher taste $&!s !ie" 8An ol! person %ay only ha#e /0 taste$&!s9 ThatLs 'hy so%e foo!s %ay taste stroner to yo& thanthey !o to an a!&lt"

Each taste $&! has /614 hairy e+tensions" These hairye+tensions are the e+tensions of the che%oreceptors"A$ons of the chemoreceptors form the nerves that carry theimpulses to the brain.


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Senses/


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Senses e ongue s v e n o reg ons an eac reg on sinvolved in the detection of di"erent tastes such as sweet,

Salty taste is !etecte! at $oth si!es of the ton&enear to the tip Salty taste is a res&lt of -l6 ion


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Senses3

bitter, salty and sour.near to the tip" Salty taste is a res&lt of -l ionpresence in the foo!"

Bitter taste is detected at the base of the tongue. ?oodsthat have al'aloid and tannin structure give bitter taste.

Sweet taste is !etecte! at the tip of the ton&e"S'eet taste is the res&lt of the che%ical content ofespecially the car$ohy!rates" There are also so%eother foo! that i#e s'eet taste $&t they are notcar$ohy!rates"

Sour taste is detected at both sides of the tongue near tothe base. our taste is a result of >L ion presence in thefood.

Mour nose helps you taste foods by smelling them before theygo in your mouth and as you chew and swallow them trong


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Senses4

go in your mouth and as you chew and swallow them. trongsmells can even confuse your taste buds: Try holding an onionslice under your nose while eating an apple. What do youtasteN

Yo&r ton&e also ets help fro% yo&r teeth0 lips0 an!%o&th" Yo&r teeth help yo&r ton&e rin! foo! as theton&e %i+es the foo! aro&n! yo&r %o&th" An!'itho&t yo&r teeth0 lips0 an! the roof of yo&r %o&th0yo&r ton&e 'o&l!nLt $e a$le to for% so&n!s to %ae

'or!s"aliva is also a friend of the tongue. A dry tongue canFt tastea thing, so saliva helps the tongue by 'eeping it wet. alivamoistens food and helps to brea' it down, which ma'es iteasier for the tongue to push the food bac' to swallow it.

Mour tongue even helps 'eep you from getting sic'.The bac' section of your tongue contains something


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Senses7

The bac' section of your tongue contains somethingcalled the lin&al tonsil.>in&al is a %e!ical 'or! that %eans ha#in

to !o 'ith the ton&e0 an! tonsils are s%all%asses of tiss&e that contain cells that helplter o&t har%f&l er%s that co&l! ca&se aninfection in the $o!y"

16SENSATION OF TASTE• A taste bud is stimulated when food molecules


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Senses3

• A taste bud is stimulated when food moleculesdissolved in saliva bind to taste cells.

• (hemoreceptors that detect odors, called

olfactory receptors, are located in the nasalpassage.• (hemicals in the air stimulate olfactory receptors,

which generate electrical signals that areinterpreted by the brain.

16SENSATION OFTASTE


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Senses31

TASTE• A taste bud is stimulated

when food molecules

dissolved in saliva anddissolved moleculesstimulate the taste cells ontaste buds.

• hen the taste cells

sti%&late0 ner#esconnecte! 'ith tastecells are sti%&late!"

• 1n the taste cells, there arereceptors for bitter, salt,sour and sweet.

• hen these receptorsare sti%&late!0 theysen! sinals to the$rain"

• And 4nally, we canunderstand tastes as bitter,


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Senses32 • ense of taste is very important in the human life, because

it alerts the body against the unsuitable substances before


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y geating and drin'ing# if they are eaten, they may causelesion in the body sooner or later.

• There is a clear cooperation $et'een sense of taste

an! sense of s%ell" In %ost cases0 !istin&ishinthe% is #ery !iKc&lt"

• =o you remember that you do not feel any taste of thefood, when you are a"ected with common cold# you 4nd thesame taste for all food when the common cold is verystrong.

Documents

Senses.pptx