l3 epithelium & glands (2)

7/24/2019 L3 Epithelium & Glands (2)

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Epithelium & GlandsGeneral Module (2010/2011)

Dr Syed Baharom Syed Ahmad Fuad

Faulty o! Mediine"ni#ersiti $e%noloi MA'A

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earnin *utomes

+ At the end o! this leture, students should -e a-le to.

de!ine the tissue & tissue types

desri-e the types, harateristis, distri-ution and

!untions o! epithelial tissue desri-e the lassi!iation o! lands -ased on

eorine and endorine seretion

desri-e the lassi!iation o! eorine lands -ased

on num-er o! ells (uni or multiellular) dut systems,seretory portion, type and mode o! seretion

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Epithelium & lands

+ ASS3F3A$3*4 *F E53$6E3A $3SS"E

+ 6A'A$E'3S$3S, F"4$3*4 &

D3S$'3B"$3*4

+ S5E3A3SED S$'"$"'E *F E53$6E3A

$3SS"E

+ ASS3F3A$3*4 *F E7*'34E GA4DS

+ E7*'34E A4D E4D*'34E GA4DS

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ells to $issues

+ As human -ody de#elops !rom sinle

to multiellular, ells speiali


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Tissues = groups of cells that are

similar in structure and function.

+ Epithelium o#erins

inins o! sur!aes

+ Connective Support

Bone, liaments,!at

+ Muscle Mo#ement

+ Nervous ontrol

Brain, ner#es,spinal ord

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The Four Basic TissuesThe Four Basic Tissues+

EpitheliumEpithelium Lining or glandular, intercellular space, junctions,

avascular

+ Connective tissueConnective tissue

intercellular space, vascularized

+ Muscle tissueMuscle tissue Elongated cells specialized for contraction (smooth,

seletal, cardiac!

+ Nervous tissueNervous tissue Elongated cells specialized to receive " send signals

(neurons!

#lial supportive cells

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harateristis o! Epithelial $issue

+Form ontinuous sheets (!it li%e tiles)+ Apial Sur!ae

All epithelial ells ha#e a top sur!ae that -orders anopen spae %no?n as a lumen

+ Basement Mem-rane

"nderside o! all epithelial ells ?hih anhors them toonneti#e tissue

+ A#asularity (a @ ?ithout)

a%s -lood #essels

4ourished -y onneti#e tissue

+ 'eenerate & repair ui%ly

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Funtion o! Epithelial $issue

+ $rotection S%in protets !rom sunliht & -ateria & physial

damae

+ %&sorption

inin o! small intestine, a-sor-in nutrients into-lood

+ Filtration

inin o! idney tu-ules !ilterin ?astes !rom -loodplasma

+ 'ecretion

Di!!erent lands produe perspiration, oil, diesti#een


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lassi!iation o!

Epithelial $issue

+ ell Shape

Suamous !lattened li%e !ishsales

u-oidal C u-es olumnar C olumns

+ ell ayers

Simple (one layer)

Strati!ied (many layers)+ 4amed !or the type o! ell at

the apial sur!ae

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lassi!iation o! Epithelium

+ 4um-er o! layers o! ells 'impleC one layer o! ells Eah etends !rom

-asement mem-rane to the !ree sur!ae

'tratifiedC more than one layer

$seudostratifiedC tissue appears to -e strati!ied,-ut all ells ontat -asement mem-rane so it is in!at simple

+ Shape o! ells

'uamousC !lat, saleCli%e Cu&oidalC a-out eual in heiht and ?idth

ColumnarC taller than ?ide

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lassi!iations o! Epithelia

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Epithelium is one o! the primary tissues $ypially it onsists o! ells that are losely

opposed to one another $he epithelial tissues are di#ided into t?o maor roups.

namely, the o#erin and linin epithelial mem-ranes and seond the landular

epithelium

o#erin & inin Epithelium

Simple Suamous

Simple u-oidal

Simple olumnar

5seudostrati!ied olumnar

Strati!ied Suamous 4on%eratini


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SIMPLE EPITHELIA

Simple squamous epithelium

Composed of a single layer of flat, scale- or plate-like cells.Nuclei are often flattened or ovoid and are located close to thecentre of the cells. The endocardium, serous membranes, blood vessels and

lymph vessels are typically lined by a simple squamous

epitheliumSimple cuboidal epithelium

Cells appear cuboidal in sections. Found in small ecretoryducts of many glands, follicles of the thyroid gland,

tubules of the kidney and on the surface of the ovaries.

Simple columnar epitheliumCells are taller than they are !ide. Nuclei are located at thesame height !ithin the cells - usually close to the base of the cells."ines the internal surface of the gastrointestinal tract #$%T& from thecardia of the stomach to the rectum.

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Simple Suamous Epithelium

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'imple 'uamous Epithelium

Capillar) *all+ "E stain+ Magnification -../+

The lining of all &lood vessels morphologicall) is a simple

suamous epithelium, and usuall) is referred to as the endothelium+

'imple 'uamous EpitheliumBo*man0s capsule+ "E stain+ Magnification 1../+

%t increased magnification note the delicate thin c)toplasm of the

simple suamous epithelial cells and the presence of prominent

ovoid nuclei

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http://www.usc.edu/hsc/dental/ghisto/epi/c_1.html


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Simple squamous epitheliumSimple squamous epithelium

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RBCRBC

'imple 'uamous (Endothelium! EM micrograph

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Simple u-oidal Epithelium

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'imple Cu&oidal Epithelium2 3enal (idne)! tu&ules+ "E stain+ Magnification -../+ 'imple cu&oidal epithelium consists of a single la)er of cells, appear to &e as

*ide as the) are tall+The upper pointer locates the supporting &asalmem&rane for the simple cu&oidal epithelium, *hile the lo*er

pointer indicates a structure called the &rush &order+

The &rush&order is composed of structures called microvilli+

'imple Cu&oidal Epithelium 2 4idne) tu&ules+ Mallor)0s stain+ Magnification -../+

Notethe cellular morpholog), the &rush &order and the

&asal mem&rane supporting the simple cu&oidal epithelium21//2010 2=MBBS220


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'imple Cu&oidal Epithelium

idney tu-ules 5eriodi aidCShi!! reation Mani!iation 900 $he periodi aidCShi!! (5AS) reation detets the presene o! ertain lyoeni

muopolysaharides $he -rush -order o! the simple u-oidal epithelium is stained a dar% redC

purple, indiatin a positi#e 5AS reation

Simple u-oidal Epithelium i#er hepati ells 6&E stain Mani!iation 900

$he hepati ells o! the li#er appear morpholoially as a type o! u-oidal epithelium in

histoloi setions

Simple u-oidal Epithelium

Germinal epithelium o! the o#ary 6&E stain Mani!iation 900

A layer o! simple u-oidal epithelium o#ers the !ree sur!ae o! the o#ary Some no? use the

term u-oidal sur!ae epithelium21//2010 2>MBBS220


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Simple olumnar Epithelium

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'imple Columnar Epithelium

#all &ladder+ "E stain+ Magnification -../+

onitudinal setions o! simple olumnar epithelium re#eal ells that are tall, elonated,prismati in morpholoy, and ?ith an o#oid nuleus usually loated to?ard the -asal end o! the ell

Simple olumnar epithelial ells rest upon a thin -asement mem-rane


#all &ladder+ "E stain+ Magnification 1../+

*n the !ree sur!ae o! the tall olumnar ells the presene o! a dar%er stainin -and !ormin a

struture %no?n as the striated -order i%e the -rush -order in u-oidal ells, the striated -order is

omposed o! miro#illi


5uodenal area of the small intestine+ "E stain+ Magnification -../+

Sinle ro? o! tallCelonated prismati ells $he pointer on the le!t side o! the indiates the

striated -order, ?hile the larer pointer terminates in the muus plu o! a o-let ell

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Simple columnarSimple columnar

epitheliumepithelium

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Simple cuboidal epitheliumSimple cuboidal epithelium

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5seudostrati!ied iliated olumnar Epithelium

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ClassificationsClassifications Typical LocationsTypical Locations Major FunctionsMajor Functions

Types of EpitheliumTypes of Epithelium

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'T3%T6F6E5 E$6TEL6%

'tratified suamous epithelium

Strati!ied suamous epithelia #ary in thi%ness dependin on the

num-er o! ell layers present$hedeepest ells, ?hih are in ontat ?ith the

-asement mem-rane, areu-oidal orolumnar in shape $his layer is usually

named the-asal elllayer, and the ells are alled -asal ells Basal ells are

mitotially ati#e and replae the ells o! the epithelium$he -asal ell layer is

!ollo?ed -ylayers o! ells ?ith polyhedraloutlines lose to the sur!aeo! the

epithelium,ells -eomemore !lattenedAt the sur!aeo! the epithelium, ellsappear li%e !lat salesC similar to the epithelial ells o! simple suamous

epithelia

'tratified cu&oidal and columnar epithelia

are not ommonA t?oClayered u-oidal epitheliumis seen in the dutso! the s?eat lands

Strati!ied olumnar epitheliaare !ound in the eretory duts o! the

mammary land and the main eretory dut o! the lare sali#ary lands

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Strati!ied Epithelia

+ ontain t?o or more layers o! ells

+ 'eenerate !rom -elo?

+ Maor role is protetion+ Are named aordin to the shape o! ells

at apial layer

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Strati!ied Suamous Epithelium

+ Desription

Many layers o! ells suamous in shape

Deeper layers o! ells appear u-oidal or

olumnar

$hi%est epithelial tissue adapted !or

protetion

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+ Spei!i types

eratini


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+ Funtion 5rotets underlyin tissues in

areas su-et to a-rasion

+ oation

eratini


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Figure !"e21//2010 92MBBS220


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PSEUDOSTRATIFIED AND TRANSITIONAL EPITHELIA

Transitional epitheliumTransitional epithelium is found mainl) in the e/cretor) urinar) passages

(the renal cal)ces and pelvis, the ureter, the urinar) &ladder, and part

of the urethra!+ The shape of the cells varies*ith the degree of distension of the

organs+ 6t appears to &e formed &) man) cell la)ers in rela/ed state+The

most &asal cells have a cu&oidal or columnar shape+

There are several la)ers of pol)hedral cells, " a la)er of superficial cells,

*hich have a conve/, dome7shaped luminal surface+

6n the distended stateit consists of 879 la)ers of cu&oidal cells follo*ed

&) a superficial la)er of large, lo* cu&oidal or suamous cells+

$seudostratified columnar epithelium

%ll cells of this t)pe of epithelium are in contact *ith the &asement

mem&rane, &ut not all of them reach the surface of the epithelium+ The nuclei of cells are often located at different heights*ithin the

epithelium and give the epithelium a stratified appearance+

$seudostratified columnar epithelia are found in the e/cretor) ducts

of man) glands+

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$ransitional Epithelium


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$ransitional Epithelium

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Transitional epithelium

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Types of EpitheliumTypes of Epithelium


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ClassificationsClassifications Typical LocationsTypical Locations Major FunctionsMajor Functions

Types of Epitheliumyp p

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'$EC6%L C:T;L;#6C%L FE%T


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'$EC6%L C:T;L;#6C%L FE%T


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Epithelial Sur!ae Features

+ Apial sur!ae !eatures Miro#illi !inerCli%e etensions o! plasma

mem-rane

+ A-undant in epithelia o! small intestine and %idney

+ Maimi


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+ Etensions o! ell mem-rane (1C2m)

+ Some ontain atin

+ Funtion inrease sur!ae area !or a-sorption

+ -rush -order o! small intestine

mil%in ation o! atin+ atin !ilaments shorten miro#illi

pushin a-sor-ed ontents do?n into ell

Miro#illi

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+ irular !olds (pliae irularis)up to 10 mm tall

in#ol#e only muosa and su-muosa hyme !lo?s in spiral path ausin more ontat

Small 3ntestine C Sur!ae Area

+ illi are !inerli%e proetions 1

mm tall

ontain -lood #essels andlymphatis (lateal)

+ nutrient a-sorption

+ Miro#illi 1 miron tall

o#er sur!ae

-rush -order on ells -rush -order en


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ross Setion o! a Miro#illus

#ote$ actin microfilaments are found in center of each micro%illi!

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ilia


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ilia+ 6airli%e proesses C10m lon

sinle, nonmotile ilium !ound on nearly e#ery ell Sensory in inner ear, retina and nasal a#ity

+ Motile ilia -eat in ?a#es

po?er stro%es !ollo?ed -y reo#ery stro%es

Chloride pumps produce

saline la)er at cell

surface+ Floating mucuspushed along &) cilia+

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Fiure 811a

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Fiure 811

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Fiure 812a

Muus traps Hstu!!,I ilia mo#es the Hstu!!I out o! the ?ay Best eample is

pseudostrati!ied iliated olumnar epithelial ells o! the upper respiratory

trat and the male urethra

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5seudostrati!ied iliated olumnar epithelium21//2010 ;8MBBS220


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Epithelium. Glandular

+ A land is one or more ells that ma%es and seretesan aueous !luid

+ $?o types o! lands !ormed -y in!oldin o! epithelium.

Endocrine. no ontat ?ith eterior o! -ody ductless produe

hormones (pituitary, thyroid, adrenals, panreas) E/ocrine. open to eterior o! -ody #ia duts (s?eat, oil)

+ Eorine lands lassi!ied either -y struture or -y the

method o! seretion

+ lassi!ied -y struture "niellular. goblet cells Multiellular. s?eat, oil, pituitary, adrenal

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Multiellular Eorine Glands

+ lassi!ied on the -asis o! types o!duts or mode o! seretion

+ $ypes o! duts

Simple. duts ?ith !e?

-ranhes ompound. duts ?ith many

-ranhes

+ 3! duts end in tu-ules orsaCli%e strutures. acini5anreas

+ 3! duts end in simplesas. alveoliuns

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#L%N5'll ti ! ll h ! ti i ti


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are ells or areations o! ells ?hose !untion is seretion

Eorine landsrelease the seretory produt #ia duts ?hile

Endorine landsrelease their seretory produt (typially hormones) into the

etraellular spae !rom ?hih it enters the -loodstream

Both endorine and eorine lands are deri#ed !rom epithelialassi!iation o! Eorine Glands

Eorine lands may -e lassi!ied aordin to ell num-er, and/or the shape and

-ranhin pattern o! their seretory portions and duts

"niellular Glands

onsist o! a sinle seretory ell e o-let ells Go-let ells serete the

lyoprotein muin, ?hih -y the upta%e o! ?ater is on#erted into a slimy

su-stane, muus

Multiellular lands

$he simplest !orm o! a multiellular land is a seretory epithelial sheath

sur!ae epithelium onsistin entirely o! seretory ells (e the epithelium

linin the innersur!ae o! the stomah, ?here the muous seretion

protets the stomah ?all !rom the aidi ontents o! the stomah) *ther multiellular landsha#e their seretory portion em-edded in the

onneti#e tissue underlyin the epithelium $he seretion is either

dishared diretly !rom the seretory portion onto the epithelium or reahes

the epithelium #ia a dut system

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$he seretory portion may ha#e a #ariety o!


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shapes Seretory ells may !orm tubes

in tu-ular lands, aini in ainar lands or

al#eoli in al#eolar lands

$he panreas is atu-uloCainar land, in ?hih eah setion o!

the seretory system has a speiali


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#landular epithelium#landular epithelium

E&ocrine'( ducts

Endocrine

'(o ducts

)cinar Tubular Tubuloacinar)cinar Tubular Tubuloacinar

Simple

CompoundCompound

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* based on* based onProduct(s) released (serous, mucous, mixed)Product(s) released (serous, mucous, mixed)


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Sublingual +arotid Submandibular

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'ecretor) Mechanisms


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$he seretory ells an release their seretory

produts -y one o! three mehanisms

6n Merocrine secretion#esiles open onto the sur!ae o! the ell, and theseretory produt is dishared !rom the ell ?ithout any !urther loss o! ell

su-stane

6n %pocrine secretion part o! the apial ytoplasm o! the ells is lost toether?ith the seretory produt $he ontinuity o! the plasma mem-rane is restored -y

the !usion o! the -ro%en edes o! the mem-rane, and the ell is a-le to aumulatethe seretory produt ane? eaporine s?eat lands, the mammary lands and

the prostate

6n olocrine secretionthe -rea%do?n and dishare o! the entire seretory ellese-aeous lands o! the s%in

$here are t?o additional mehanisms -y ?hih seretory ells an release their

produts ipid solu-le su-stanes may di!!use outo! the seretory ell (e steroid

hormone produin endorine ells) $ransporters (mem-rane proteins) may

ati#ely mo#ethe seretory produt aross the plasma mem-rane (e the aid

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* based on* based on Method of SecretionMethod of Secretion


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based on based onMethod of SecretionMethod of Secretion

,olocrine Merocrine )pocrine

-'hole cells. -%esicles. -cell parts.

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'T3


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$he entire gland is surrounded by alayer of denseconnective tissue'the capsule.Connective tissue sheets #septa&etend from the capsule into the secretory tissueand subdivide the gland into a number of lobes. Thinner connective tissue septasubdivide thelobes into a number of lobules.

Reticular connective tissuesurrounds and supports the secretory units of theglands #alveoli, acini etc.& and the initial parts of the ecretory ducts .

Blood and ly!" vessels#and nerves penetrate the capsule and form adelicate net!ork bet!een the secretory units and the initial parts of the duct

system.

T"e ain e$cretory ductconveys the secretory product to one of the eternalsurfaces of the body.Lo%ar ductsare are large branches of the main duct !hich etend to the lobes ofthe gland.Interlo%ar ducts are found in the connective tissue surrounding the lobes.%nterlobar ductsbranch and give rise to %nterlobular ducts, !hich are found in theconnective tissue surrounding the individual lobules of the gland. (ranches of theinterlobular ducts enter the lobules and are no! called %ntralobular ducts.The terminal branches of the duct system, !hich connect intralobular ducts !iththe secretory units of the gland, are called %ntercalated ducts.

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'$EC6%L6'%T6;N' ;F TE L%TE3%L %N5 B%'%L '


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'$EC6%L6'%T6;N' ;F TE L%TE3%L %N5 B%'%L ' ti


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Epithelial Cell >unctions

Three t)pes of cell junctions2

8 ;ccluding junction2lin% ells to !orm an impermea-le

-arrier Also alled tiht untion9 %nchoring junctions2lin% ellsto pro#ide mehanial

strenth $heylin% the ytos%eletono! the ells -oth to

eah other and to underlyin tissues

Desmosomesonnet the intermediate !ilamentnet?or% o! adaent ellsJell de#eloped in

strati!ied suamous epithelium o! the s%in

6emidesmosomesonnet the intermediate !ilament

net?or% o! ells to etraellular matri

? Communicating junctions2allo? moleules to mo#e-et?een ells ell to ell ommuniationorKap untionL

A untional ompleonsists o! se#eral types o! epithelial ellattahments

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Mem-rane untions. $iht untion


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e - a e u t o s t u t o

+ 3nteral proteins o!

adaent

ells !use toether

+ ompletely enirle theell

and !orm an adhesion belt.+ Form an impermeable

junction.+ ommon near apial

reion

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Mem-rane untions. Desmosome


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Mem-rane untions. Desmosome

Linker proteinsetend !rom

plaue li%e teeth o! a


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Mem-rane untions. Gap untion

+ Connexonproteins are

transCmem-rane

proteins+ 5resent in eletrially

eita-le tissues (heart,

smooth musle)

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' !


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'e!erenes

+ Noun B, o?e S, et al, eds (200;) JheaterLsFuntional 6istoloy :thed hurhill i#instone

+ Eroshen%o, 5 (200>) di F3ioreLs Atlas o! 6istoloy, 11th

ed ippinott, Jilliams & Jil%ins

+ http.//ell-ioutm-edu/miroanatomy/epithelia/pratieOpratialOeamhtm

+ http.//???la-anh-u?aeduau/m-190/

+ A pa%aes. Anatomedia C General Anatomy

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$han% youP

syed-aharomQsalamuitmedumy

08::2112=

l3 epithelium & glands (2)

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