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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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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
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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
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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
'imple Columnar Epithelium
#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
'imple Columnar Epithelium
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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Strati!ied Suamous Epithelium
+ Spei!i types
eratini
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Strati!ied Suamous Epithelium
+ Funtion 5rotets underlyin tissues in
areas su-et to a-rasion
+ oation
eratini
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Strati!ied Suamous Epithelium
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) $ransporters (mem-rane proteins) may
ati#ely mo#ethe seretory produt aross the plasma mem-rane (e the aid
produin parietal ells o! the astri lands)21//2010 9MBBS220
* based on* based on Method of SecretionMethod of Secretion
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based on based onMethod of SecretionMethod of Secretion
,olocrine Merocrine )pocrine
-'hole cells. -%esicles. -cell parts.
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'T3
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$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
21//2010 =MBBS220
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
21//2010 >MBBS220
Mem-rane untions. Desmosome
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80/86
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)
21//2010 =1MBBS220
7/24/2019 L3 Epithelium & Glands (2)
82/86
21//2010 =2MBBS220
7/24/2019 L3 Epithelium & Glands (2)
83/86
21//2010 =8MBBS220
7/24/2019 L3 Epithelium & Glands (2)
84/86
21//2010 =9MBBS220
' !
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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
21//2010 MBBS220 =:
7/24/2019 L3 Epithelium & Glands (2)
86/86
$han% youP
syed-aharomQsalamuitmedumy
08::2112=
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