human physiology related to ear

7/24/2019 human physiology related to ear

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ONLINE ASSIGNMENT ON

HUMAN PHYSIOLOGY

RELATED TO EAR.

Submitted by : Sreya k

Natural science


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INTRODUCTION

The vertebrate ear is the sensory organ resonsib!e "or hearing an# ba!an$ing.

There "ore% it is re"erre# to as statoa$o&sti$ organ. It is $o'ose# o" three arts(the

e)terna! ear% 'i##!e ear an# the inner ear. H&'an ear is sensitive to so&n# vibration

in the range o" *+ to *++++ H, -ith 'a)i'&' sensitivity at abo&t *+++H,.The

ear is a aire# sensory organ% -hi$h is invo!ve# in both hearing an# ba!an$e. orthis reason% the ear is /no-n as the vestib&!o$o$h!ear organ. oreign bo#ies $an

be$o'e !o#ge# in the e)terna! aitory 'eat&s% b&t g!an#s are resent that ro#&$e

-a) -hi$h $an tra these.


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The Physiology of earing

The hysio!ogy o" o&r hearing 'e$hanis' $an $onvenient!y be #ivi#e# into threetoi$s0

1The o&ter ear 2a&ri$!e or inna3 an# ear $ana!

* The 'i##!e ear

4 The inner ear

The Auricle and Ear Canal.

Ea$h ho!e in the si#e o" the s/&!! !ea#s into an ear $ana!. The ear $ana! is an

irreg&!ar $y!in#er -ith an average #ia'eter o" !ess than +.5 '' an# abo&t *.6 $'

!ong.

The ear $ana! 2"ig&re 13 is oen at the o&ter en# -hi$h is s&rro&n#e# by the inna

2or a&ri$!e3. The inna !ays an i'ortant sa$ia! "o$&sing ro!e in hearing. The

$ana! then narro-s s!ight!y an# -i#ens to-ar#s its inner en#% -hi$h is sea!e# o""

by the ear#r&'.

Th&s the $ana! is a shae# t&be en$!osing a resonating $o!&'n o" air ( -ith the

$o'bination o" oen an# $!ose# en#s. This 'a/es it rather !i/e an organ ie.


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THE EAR 7ANAL

The ear $ana! s&orts 2resonates or enhan$es3 so&n# vibrations best at the

"re8&en$ies -hi$h the h&'an ears hear 'ost shar!y. This resonan$e a'!i"ies the

variations o" air ress&re that 'a/e & so&n# -aves% !a$ing a ea/ ress&re

#ire$t!y at the ear#r&'.

or "re8&en$ies bet-een aro)i'ate!y * 9H: an# 6.6 9H:% the so&n# ress&re

!eve! at the ear#r&' is aro)i'ate!y 1+ ti'es the ress&re o" the so&n# at the

a&ri$!e.

The Eardrum - interface between outer and middle ear.

Airborne so&n# -aves rea$h on!y as "ar as the ear#r&'. Here they are $onverte#into 'e$hani$a! vibrations in the so!i# 'ateria!s o" the 'i##!e ear.

So&n#s 2air ress&re -aves3 "irst set & sy'atheti$ vibrations in the ta&nt

'e'brane o" the ear#r&'% ;&st as they #o in the #iahrag' o" so'e tyes o"

'i$rohone. The ear#r&' asses these vibrations on to the 'i##!e ear str&$t&re.


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!iddle "ar

The 'i##!e ear $onsists o" the ty'ani$ $avity% the aitory ossi$!es an# the

e&sta$hian t&be.

The bo&n#ary bet-een the 'i##!e an# inner ear is the ova! -in#o-.

The aitory ossi$!es are atta$he# to the -a!! o" the ty'ani$ $avity by

'any !iga'ents an# '&$osa! "o!#s.

The ty'ani$ $avity is !o$ate# -ithin the etro&s te'ora! bone% an# $an be

#ivi#e# into #orsa!% 'i##!e an# ventra! arts0


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(Dorsal0 or epitympanum% $onatining * o" the aitory ossi$!es


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The 'e'brano&s !abyrinth is an inter$onne$te# gro& o" "!&i#("i!!e#

'e'brano&s sa$s. The "!&i# is en#o!y'h.

It is the 'ove'ent o" the en#o!y'h that sti'&!ates the sensory $e!!s -ithin

the 'e'brano&s -a!!.

#unction $ earing

The 'ain "&n$tion o" the ear is to re$eive aitory an# vestib&!ar in&t. It !o$ates

the #ire$tiona! so&r$e o" so&n#% $o!!e$ts so&n# -aves an# $on#&$ts the' to the

se$ia! organ o" sense in the inner ear% -here so&n# is $onverte# to e!e$tri$a!

i'&!ses an# trans'itte# to the brain.

The e)terna! ear re$eives so&n#s% -hi$h $a&se vibrations o" the ty'ani$

'e'brane. These vibrations 'ove a!ong the ossi$!es o" the 'i##!e ear% to be

trans'itte# to the inner ear. The staes is $onne$te# to the ova! -in#o-% so -hen

the staes trans'its vibrations% this $a&ses 'ove'ent o" eri!y'h that is in the

inner ear. The 'ove'ent o" the eri!y'h is trans'itte# via the s$a!a vestib&!i an#

the s$a!a ty'ani% to the ro&n# -in#o-% -here it in#&$es 'ove'ent o" the

se$on#ary ty'ani$ 'e'brane. This res&!ts in the 'ove'ent o" the en#o!y'h o"

the $o$h!ear #&$t% $a&sing ress&re on the te$toria! 'e'brane% -hi$h then in#&$es

ress&re on the sensory hairs% sti'&!ating the re$etor $e!!s -ithin the $o$h!ear

#&$t to sen# i'&!ses to the sira! gang!ion. The a)ons o" the sira! gang!ion "or'

art o" the vestib&!o$o$h!ear nerve.

ty'ani$ 'e'brane = ossi$!es = 'i##!e ear -a!! = 'i##!e ear $avity = ova!

-in#o-

#unction $ %alance The vestib&!ar sense is rather 'ore &n$ons$io&s than that o" hearing.

The vestib&!ar !abyrinth% that is $ontaine# -ithin the bony !abyrinth o" the inner

ear is the art o" the ear that is invo!ve# -ith the vestib&!ar sense ( ba!an$e.


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The vestib&!ar !abyrinth $ontains the sa$$&!e% the &tri$!e an# the se'i$ir$&!ar

#&$ts ( the se'i$ir$&!ar #&$ts being ho&se# -ithin the se'i$ir$&!ar $ana!s.

There are sensory hair $e!!s -ithin the vestib&!ar !abyrinth% si'i!ar to those in

the other regions o" the inner ear% -hi$h #ete$t 'ove'ent.

Ho-ever% these sensory hair $e!!s are !o#ge# in the a'&!!ary $&&!ae or in

oto!iths 2'in&te $a!$areo&s arti$!es3% rather than in the te$toria! 'e'brane as

in the rest o" the ear.

The a'&!!a is a s-e!!ing at the base o" the se'i$ir$&!ar #&$ts. The sensory hair

$e!!s ro;e$t &-ar#s "ro' the a'&!!a into the $&&!a% -hi$h is a ge!atino&s

'ass. The a'&!!ary $&&!ae #ete$t "!o- aro&n# the se'i$ir$&!ar $ana!s% -hi$h

are "i!!e# -ith en#o!y'h% an# there is an inertia o" "!&i# "or #ete$tion o"ang&!ar a$$e!eration. Ang&!ar a$$e!eration is the #ete$tion o" 'otion o" the hea#

in any #ire$tion.

Oto!iths are #enser than en#o!y'h ( they are $a!$areo&s an# $rysta!!ine. They

are $ontaine# -ithin the 'a$&!ae% an# #ete$t gravity an# !inear a$$e!eration.

Linear a$$e!eration is the #ete$tion o" 'otion a!ong a !ine% "or e)a'!e -hen

yo& !ean to one si#e.

Move'ent o" the sensory hair $e!!s triggers i'&!ses% -hi$h are $arrie# by thevestib&!ar ortion o" the vesib&!o$o$h!ear nerve3.


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"&R DIS"&S"S

Ear disease, any o" the #iseases or #isor#ers that a""e$t the h&'an ear

an# hearing.
http://www.britannica.com/science/hearing-sensehttp://www.britannica.com/science/hearing-sense


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I'aire# hearingis% -ith rare e)$etion% the res&!t o" #iseaseor abnor'a!ity o" the

o&ter% 'i##!e% or inner ear. Serio&s i'air'ent o" hearingat birth a!'ost a!-ays

res&!ts "ro' a #ys"&n$tion o" the aitory nerve an# $annot be i'rove#

by 'e#i$a!or s&rgi$a! treat'ent. In ear!y an# !ate $hi!#hoo# the 'ost "re8&ent

$a&se "or i'aire# hearing is oor "&n$tioning o" the e&sta$hian t&bes-ith the

a$$&'&!ation o" a $!ear% a!e ye!!o-ish "!&i# in the 'i##!e(ear $avity% a #isor#er

$a!!e# sero&s% or se$retory% otitis 'e#ia

Outer ear

Diseases o" the o&ter ear are those that a""!i$t s/in% $arti!age% an# the g!an#s an#

hair "o!!i$!es in the o&ter(ear $ana!. The so&n#(trans'itting "&n$tion o" the o&ter

ear is i'aire# -hen the ear $ana! be$o'es "i!!e# -ith t&'o&r% in"e$te#'ateria!%or ear-a) so that so&n# $annot rea$h the ty'ani$ 'e'brane% or ear#r&'. The

'ost $o''on #iseases o" the o&ter ear are brie"!y #es$ribe# in the "o!!o-ing

aragrahs.

Infections and in'uries

#ROST%IT"

The e)ose# osition o" the o&ter ear 'a/es it the art o" the bo#y 'ost "re8&ent!ya""e$te# by "ree:ing% or "rostbite. H&'i#ity% #&ration o" e)os&re% an#% 'ost o" a!!%

-in#% in a##ition to #egrees o" te'erat&re be!o- "ree:ing% re#isose to the

o$$&rren$e o" "rostbite. The "ro:en area begins a!ong the &er an# o&ter e#ge o"

the ear% -hi$h be$o'es ye!!o-(-hite an# -a)y in aearan$e% $o!# an# har# to the

to&$h% an# n&'b -ith !oss o" s/in sensation.

In treat'ent o" "rostbite the vi$ti' is !a$e# as soon as ossib!e in a -ar' roo'%

b&t the "ro:en ear is /et $oo! by a!ying i$e -rae# in a to-e! &nti! the

ret&rning b!oo# $ir$&!ation gra#&a!!y tha-s the "ro:en art "ro' -ithin. Massage

o" the "ro:en ear is avoi#e#% "or it is !i/e!y to in;&re the s/in. Heat a!ie# to the

"ro:en area be"ore $ir$&!ation is estab!ishe# $an res&!t in $!otting o" the b!oo# in

the b!oo# vesse!s. This in t&rn $an res&!t in #eath o" that art o" the ear% -hi$h t&rns

b!a$/ an# event&a!!y "a!!s o""% a ro$ess $a!!e# #ry gangrene.
http://www.britannica.com/science/deafnesshttp://www.britannica.com/science/diseasehttp://www.britannica.com/science/inner-earhttp://www.britannica.com/science/hearing-sensehttp://www.britannica.com/topic/otologyhttp://www.britannica.com/science/eustachian-tubehttp://www.britannica.com/science/otitis-mediahttp://www.britannica.com/science/external-earhttp://www.britannica.com/science/tumorhttp://www.britannica.com/science/frostbitehttp://www.britannica.com/science/dry-gangrenehttp://www.britannica.com/science/deafnesshttp://www.britannica.com/science/diseasehttp://www.britannica.com/science/inner-earhttp://www.britannica.com/science/hearing-sensehttp://www.britannica.com/topic/otologyhttp://www.britannica.com/science/eustachian-tubehttp://www.britannica.com/science/otitis-mediahttp://www.britannica.com/science/external-earhttp://www.britannica.com/science/tumorhttp://www.britannica.com/science/frostbitehttp://www.britannica.com/science/dry-gangrene


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"!&TO!&

In;&ry to the o&ter ear $an $a&se b!ee#ing bet-een the $arti!age an# the s/in%

ro#&$ing a s'ooth% ro&n#e#% nonten#er &r!ish s-e!!ing$a!!e# he'ato'a. The

a$$&'&!ation o" $!otte# b!oo# is re'ove# by s&rgeon be$a&se% i" it is !e"t% it -i!!

be$o'e trans"or'e# into s$ar tiss&e an# $a&se a er'anent% irreg&!ar thi$/ening o"

the o&ter ear $o''on!y $a!!e# $a&!i"!o-er earan# seen in bo)ers an# -rest!ers

-hose ears re$eive '&$h ab&se.

P"RICONDRITIS

In"e$tiono" the $arti!age o" the o&ter ear% $a!!e# eri$hon#ritis% is &n&s&a! b&t 'ay

o$$&r "ro' in;&ry or "ro' s-i''ing in o!!&te# -ater. It is #&e to a arti$&!ar'i$roorganis'%Pseudomonas aeruginosa. There is a greenish or bro-nish% '&sty

or "o&!(s'e!!ing #is$harge "ro' the o&ter(ear $ana!% -hi!e the a""e$te# o&ter ear

be$o'es ten#er% #&s/y re#% an# t-o to three ti'es its nor'a! thi$/ness. Pro't

antibioti$ treat'ent is ne$essary to revent er'anent #e"or'ity o" the o&ter ear.

"(T"RN&) OTITIS

In"e$tion o" the o&ter(ear $ana! by 'o!#s or vario&s 'i$roorganis's -ar'% h&'i#

$!i'ates an# a'ong s-i''ers. The ear $ana! it$hes an# be$o'es ten#er> a s'a!!

a'o&nt o" thin% o"ten "o&!(s'e!!ing 'ateria! #rains "ro' it. I" the $ana! be$o'es

$!ogge# by the s-e!!ing an# #rainage% hearing -i!! be i'aire#. 7are"&! an#

thoro&gh $!eaning o" the o&ter(ear $ana! by a hysi$ian% a!i$ation o" antiseti$ or

antibioti$ ear#ros% an# avoi#an$e o" s-i''ing are in#i$ate# to $!ear &

the in"e$tion.

Middle ear

&cute middle$ear infection

ort&nate!y% a$&te 'i##!e(ear in"e$tions% $a!!e# a$&te otitis 'e#ia% are near!y

a!-ays #&e to 'i$roorganis's that reson# 8&i$/!y to antibioti$s. As a res&!t% a$&te

in"e$tion o" the 'astoi# air $e!!s res&!ting in a #angero&s 'astoi# abs$ess -ith the

ossibi!ity o" 'eningitis% brain abs$ess% seti$e'ia% in"e$tion o" the !abyrinth% or
http://www.britannica.com/science/hematomahttp://www.britannica.com/science/swelling-physiologyhttp://www.britannica.com/science/cauliflower-earhttp://www.britannica.com/science/perichondritishttp://www.britannica.com/science/infectionhttp://www.britannica.com/science/Pseudomonas-aeruginosahttp://www.britannica.com/science/otitis-externahttp://www.britannica.com/science/infectionhttp://www.britannica.com/science/middle-earhttp://www.britannica.com/science/acute-diseasehttp://www.britannica.com/science/otitis-mediahttp://www.britannica.com/science/septicemiahttp://www.britannica.com/science/hematomahttp://www.britannica.com/science/swelling-physiologyhttp://www.britannica.com/science/cauliflower-earhttp://www.britannica.com/science/perichondritishttp://www.britannica.com/science/infectionhttp://www.britannica.com/science/Pseudomonas-aeruginosahttp://www.britannica.com/science/otitis-externahttp://www.britannica.com/science/infectionhttp://www.britannica.com/science/middle-earhttp://www.britannica.com/science/acute-diseasehttp://www.britannica.com/science/otitis-mediahttp://www.britannica.com/science/septicemia


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"a$ia! nerve ara!ysis% $o'!i$ating an a$&te in"e$tion o" the 'i##!e(ear $avity% has

be$o'e rare. Abs$ess o" the 'astoi# an# the other $o'!i$ations o" a$&te 'i##!e(

ear in"e$tion are seen $hie"!y in re'ote regions an# $o&ntries -here the o&!ation

!a$/s roer n&trition an# a#e8&ate 'e#i$a! $are.

?hi!e serio&s an# !i"e(threatening a$&te in"e$tions o" the 'i##!e ear an# 'astoi#

air $e!!s have be$o'e rare% $hroni$ in"e$tions% 'entione# be!o-% $ontin&e to o$$&r%

an# another tye o" 'i##!e(ear #isease% se$retory otitis 'e#ia% is "re8&ent.

S"CR"TOR* OTITIS !"DI&

In se$retory otitis 'e#ia the 'i##!e(ear $avity be$o'es "i!!e# -ith a $!ear% a!e

ye!!o-ish% nonin"e$te# "!&i#. The #isor#er is the res&!t o" ina#e8&ate venti!ation o"the 'i##!e ear thro&gh the e&sta$hian t&be. The air in the 'i##!e ear% -hen it is no

!onger re!enishe# thro&gh this t&be% is gra#&a!!y absorbe# by the '&$o&s

'e'brane% an# "!&i# ta/es its !a$e. Event&a!!y% the 'i##!e(ear $avity is

$o'!ete!y "i!!e# -ith "!&i# instea# o" air. The "!&i# i'e#es the vibratory

'ove'ents o" the ty'ani$ 'e'brane an# the ossi$&!ar $hain% $a&sing a ain!ess

i'air'ent o" hearing.

The &s&a! $a&ses "or se$retory otitis 'e#ia are an a$&te hea# $o!#-ith s-e!!ing o"

the 'e'branes o" the e&sta$hian t&be% an a!!ergi$ rea$tion o" the 'e'branes in the

e&sta$hian t&be% an# an en!arge# a#enoi# 2no#&!e o" !y'hoi# tiss&e3 b!o$/ing the

entran$e to the e&sta$hian t&be. The $on#ition is $&re# by "in#ing an# re'oving the

$a&se an# then re'oving the "!&i# "ro' the 'i##!e(ear $avity% i" it #oes not

#isaear by itse!" -ithin a -ee/ or t-o. Re'ova! o" the "!&i# re8&ires &n$t&ring

the ty'ani$ 'e'brane an# "or$ing air thro&gh the e&sta$hian t&be to b!o- o&t the

"!&i#. In the absen$e o" "ever an# in"e$tion o" the 'i##!e ear% antibioti$s% -hi$h

'ay i'e#e the nor'a! i''&ne rote$tion o" the 'i##!e ear% are not ne$essary. In

$ases in -hi$h an a!!ergi$ rea$tion is not the &n#er!ying $a&se o" the $on#ition% it

'ay be ne$essary to insert a tiny !asti$ t&be thro&gh the 'e'brane to ai# in

reestab!ishing nor'a! venti!ation o" the 'i##!e(ear $avity. A"ter a ti'e% -hen the

'i##!e ear an# hearing have ret&rne# to nor'a!% this !asti$ t&be is re'ove#. The

s'a!! ho!e !e"t in the ty'ani$ 'e'brane 8&i$/!y hea!s.
http://www.britannica.com/science/secretory-otitis-mediahttp://www.britannica.com/science/common-coldhttp://www.britannica.com/science/secretory-otitis-mediahttp://www.britannica.com/science/common-cold


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&"RO$OTITIS !"DI&

Aero(otitis 'e#ia is a ain"&! tye o" hearing !oss that $an res&!t "ro' an inabi!ity

to e8&a!i:e the air ress&re in the 'i##!e(ear $avity -hen a s#en $hange in

a!tite o$$&rs% as 'ay haen in a rai# #es$ent in a oor!y ress&ri:e# air$ra"t.

A!!ergies or a ree)isting hea# $o!# 'ay inhibit an in#ivi#&a!@s abi!ity to e8&a!i:e%

-hi$h is a$$o'!ishe# by ya-ning or s-a!!o-ing to oen the e&sta$hian t&be.The

ty'ani$ 'e'brane be$o'es shar!y retra$te# -hen the air ress&re be$o'es !ess

-ithin than -itho&t% -hi!e the oening o" the t&be into the &er art o" the throat

be$o'es resse# tight!y together by the in$rease# air ress&re in the throat% so that

the t&be $annot be oene# by s-a!!o-ing. A severe sense o" ress&re in the ear is

a$$o'anie# by ain an# a #e$rease in hearing. So'eti'es the ty'ani$

'e'brane r&t&res be$a&se o" the #i""eren$e in ress&re on its t-o si#es. More

o"ten% the ain $ontin&es &nti! the 'i##!e ear "i!!s -ith "!&i# or the 'e'brane is

s&rgi$a!!y &n$t&re#. Us&a!!y aero(otitis 'e#ia ro#&$e# #&ring a "!ight is o" a

te'orary nat&re an# #isaears o" its o-n a$$or#.

7ON7LUSION
http://www.britannica.com/science/ear-squeezehttp://www.britannica.com/science/eustachian-tubehttp://www.britannica.com/science/ear-squeezehttp://www.britannica.com/science/eustachian-tube


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Our ear has three 'ain arts0 o&ter% 'i##!e an# inner.-e &se a!! o" the' in hearing.

So&n# -aves $o'e in thro&gh yo&r o&ter ear. They rea$h yo&r 'i##!e ear% -here

they 'a/e yo&r ear#r&' vibrate. The vibrations are trans'itte# thro&gh three tiny

bones% $a!!e# ossi$!es% in yo&r 'i##!e ear. The vibrations trave! to yo&r inner ear% a

snai!(shae# organ. The inner ear 'a/es the nerve i'&!ses that are sent to thebrain. Yo&r brain re$ogni:es the' as so&n#s. The inner ear a!so $ontro!s ba!an$e.

REEREN7E


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1. 9. i;aya/&'aran nair an# P.I Pa&!% *++B> Ani'a! hysio!ogy an#

biote$hno!ogy% A$a#e'ia &b!i$ations.

*. 9.9.Chas/aran> Ani'a! Physio!ogy an# En#o$rino!ogy% Man;&sha

&b!i$ation.

4. ---.-i/ee#ia.$o'.
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human physiology related to ear