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aboutabout 2525--cmcm --longlong muscularmuscular tubetube

functionfunction :: forwardingforwarding swallowedswallowed foodfood fromfromthethe pharynxpharynx downdown intointo thethe stomachstomach

itsits lumen islumen is starstar --shapedshaped ,, duedue toto thethelongitudinallongitudinal reservereserve foldsfolds

thethe typicaltypical structurestructure of of thethe alimentaryalimentary canalcanal

appearsappears inin thisthis segmentsegment

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epitheliumepithelium ((laminalamina epithelialisepithelialis mucosaemucosae ):):stratifiedstratified ,, nonkeratinizednonkeratinized squamoussquamousepitheliumepithelium atat itsits entireentire lengthlength

laminalamina propriapropria mucosaemucosae comprisescomprises cardiaccardiacesophagealesophageal glandsglands ((glandulaeglandulae oesophageaeoesophageaecardiacaecardiacae )) inin itsits beginingbegining andand terminalterminalportionsportions ;; thesethese glandsglands resembleresemble thethe cardiaccardiacglandsglands , hence, hence thethe namename

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cardiaccardiac esophagealesophageal glandsglands produceproduce neutralneutral mucin,mucin,whichwhich protectsprotects thethe cellscells againstagainst thethe possiblepossible refluxrefluxof of gastricgastric juice juiceinin thethe laminalamina propriapropria ,, therethere areare scatteredscattered lymphaticlymphaticelementselements ,, frequentlyfrequently inin thethe vicinityvicinity of of thethe excretoryexcretoryductsductslaminalamina muscularismuscularis mucosaemucosae isis composedcomposed of of mainlymainlylongitudinallongitudinal smoothsmooth musclemuscle cellscells

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isis thrownthrown intointo longitodinallongitodinal foldsfolds ,, just just likelikemucousmucous membranemembranetherethere areare mixedmixed oror purelypurely mucousmucous smallsmall

salivarysalivary glandsglands ,, whichwhich areare calledcalled esophagealesophagealglandsglands properproper ((glandulaeglandulae oesophageaeoesophageaepropriaepropriae ))

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beanbean --shaped hollow muscular organ of theshaped hollow muscular organ of thegastrogastro --intestinal tract involved in the secondintestinal tract involved in the secondphase of digestionphase of digestion

itit hashas fourfour anatomicalanatomical partsparts :: cardiacardia , fundus,, fundus,bodybody andand pyloruspylorusitit hashas threethree histologicalhistological distinctdistinct partsparts : (1): (1)cardiacardia , (2), (2) thethe fundusfundus andand thethe bodybody havehave thethe

samesame histologicalhistological propertiesproperties , (3), (3) pyloruspylorus

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simplesimple columnarcolumnar epitheliumepithelium invaginatesinvaginatesintointo thethe laminalamina propriapropria ,, therebythereby itit makesmakesgastricgastric pitspits ((foveolaefoveolae gastricaegastricae ))

thethe tubulartubular glandsglands ((cardiaccardiac --,, fundicfundic -- andandpyloricpyloric glandsglands )) of of stomachstomach emptyempty intointo thethebottombottom of of thethe gastricgastric pitspitsthethe epithelialepithelial cellscells produceproduce thick thick ,, neutralneutral

mucinmucin ,, whichwhich protectsprotects thethe cellscells themselvesthemselvesfromfrom highlyhighly acidicacidic gastricgastric juice juice

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looseloose connectiveconnective tissuetissue ,, whichwhich maymay containcontainmanymany lymphocyteslymphocytesallall thethe gastricgastric glandsglands areare locatedlocated inin thisthis laminalamina

inin thethe threethree histologicalhistological portionsportions of of thethestomachstomach thethe glandsglands displaydisplay somewhatsomewhatdifferentdifferent morphologymorphology ;; theirtheir productsproducts areare alsoalsodifferentdifferent

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aa laminalamina muscularismuscularis mucosaemucosaewellwell --developeddeveloped ,, usuallyusually isis composedcomposed of of twotwo sublayerssublayersof of smoothsmooth musclemuscle cellscells

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looseloose coonectingcoonecting tissuetissue ,, containingcontainingbloodblood vesselsvessels

lymphaticslymphatics

lymphocyteslymphocytessolitarysolitary fatfat cellscells

macrophagesmacrophages

mastmast cellscells

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containscontains smoothsmooth musclemuscle cellscellscomposedcomposed of of sublayerssublayers ::

outermostoutermost sublayersublayer :: discontinuousdiscontinuous ;; comprisecomprise mainlymainlylongitudinallylongitudinally orientedoriented smoothsmooth musclesmuscles cellscells ,, whichwhich maymay

bebe absentabsent fromfrom areasareas withinwithin thethe pyloricpyloric portionportionmiddlemiddle sublayersublayer :: circularlycircularly arrangedarranged smoothsmooth musclemuscle cellscells ,,wellwell --developeddeveloped throughoutthroughout thethe stomachstomach ;; thethe middlemiddlesublayersublayer isis greatlygreatly enhancedenhanced inin thethe pyloricpyloric portionportion ,, wherewhereitit isis calledcalled pyloricpyloric sphinctersphincter musclemuscle

innermostinnermost sublayersublayer :: obliqueoblique bundlesbundles of of smoothsmooth musclemusclecellscells maymay occuroccur

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TheThe stomachstomach isis anan intraperitonealintraperitoneal organorgan .. ItsItsoutermostoutermost mainmain layerlayer isis aa serousserous membranemembraneof of looseloose coonectivecoonective tissuetissue andand mesotheliummesothelium

towardstowards thethe peritonealperitoneal cavitycavity ..

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locatedlocated inin thethe laminalamina propriapropria ,, whichwhich arearedifferentdifferent inin thethe histologicalhistological portionsportions ::

cardiaccardiac glandsglands

fundicfundic glandsglandspyloricpyloric glandsglands

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branchedbranched tubulartubular glandsglandsseveralseveral glandsglands openopen intointo oneone gastricgastric pitpithavehave segmentssegments

inin thethe upperupper segmentsegment (( neck neck ))neck neck mucousmucous cellscellsundifferentiatedundifferentiated stemstem cellscells

inin thethe middlemiddle andand lowerlower segmentssegments ((principalprincipalsegmentsegment ))

H ClH Cl --producingproducing parietalparietal cellscellschief chief cellscells ,, whichwhich secretesecrete pepsinogenpepsinogenenteroendocrineenteroendocrine cellscells

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inin thethe pyloricpyloric regionregion ,, thethe gastricgastric pitspits arearedeeperdeeper thanthan inin thethe otherother onesonesthethe pyloricpyloric glandsglands areare branchedbranched tubulartubular

glandsglands

withwith

curvedcurved

endsends

thethe secretorysecretory cellscells stainstain lightlylightlytheythey produceproduce mucinmucin andand antibacterialantibacteriallysozymelysozyme

enteroentero --endocrineendocrine cellscells areare alsoalso presentpresent

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