组织学与胚胎学11 消化管

DigestiveTract消化管Histology14layersinitswall.A.Mucosa粘膜

:segments.1.Epithelium上皮:Simplecolumnarorstratifiedsquamous.2.Laminapropria固有层:LCT,maycontainglandsandlymphatictissue.Mayprotrudetogetherwithepitheliumintothetractlumentoform

villi.I.Generalstructuresofdigestivetract:23.Muscularismucosa粘膜肌层:Innercircularandouterlongitudinallayerofsmoothmuscles.B.Submucosa粘膜下层:LCTcontaininglargernervefibers,bloodandlymphvessels.Maycontainsubmucosalglands.Mayprotrudetogetherwithmucosaintothetractlumentoform

plicae皱襞.C.Muscularis肌层(--externa):

Skeletalmusclesand/orsmoothmusclesarearrangedinto2~3layers.D.serosa浆膜:Serousmembrane.or

fibrosa纤维膜:fibrousmembrane.

3Schematicstructureofaportionofthedigestivetractwithvariouscomponentsandtheirfunction.4Generalstructureoforalmucousmembrane口腔粘膜Epithelium上皮:Laminapropria固有层:containsmallsalivarygland小唾液腺,richinCap,NE,SkeletalmuscleNomuscularismucosa无粘膜肌层感觉神经末梢丰富5Tongue舌Muccosa:lingualpapillae舌乳头:elevationsoftheepi.AndlaminarpropriaSkeletalmucles6Filiformpapillae:丝状乳头Numerous,presentoverTheentiresurface.Theepi.iskeratinizedFungiformpapillae菌状乳头Resemblemushrooms,irregularlyinterspreadamongthethefiliformpapillae.containscatteredtastebuds味蕾ontheiruppersurfaceCircumvallatepapillae轮廓乳头DistributedintheVregionintheposteriorportionofthetongue.

7菌状乳头丝状乳头结缔组织神经纤维味腺脂肪细胞图4C舌菌状乳头和丝状乳头光镜像8结缔组织未角化的复层扁平上皮环沟味蕾神经纤维味腺图4B舌轮廓乳头光镜像9Tastebud味蕾10味觉感受器，卵圆形小体，主要分布于菌状乳头和轮廓乳头，由三种细胞组成：

1.暗细胞

2.明细胞

3.基细胞：干细胞，可相继分化为暗细胞和明细胞味觉细胞；长梭形，游离面有微绒毛伸入味孔，基底面有突触11Teeth牙12A.Mucosa:Non-keratinizedstratifiedsquamousepithelium未角化的复层扁平上皮.B.Submucosa:Containsesophageal

mucusglands食管腺.Mucosaandsubmucosaprotrudetogetherintothelumen,forming7~10

longitudinalplicae皱襞,whichdisappearandreappeardependinguponthepassageoffood.II.Esophagus食管13C.Muscularis肌层:Skeletalinupper1/3,

mixed

inmiddlepartand

smooth

musclefibersinlower1/3part.Arrangedininnercircularandouterlongitudinallayer.D.Adventitia:Fibrous

membraneofLCT.纤维膜14Photomicrographofasectionofesophagus.Esophagusglandsareinthesubmucosa.15A.Mucosa:surfaceepitheliuminvaginatetoformgastricpit胃小凹.

1.Epithelialcells:Mainlycomposedofsurfacemucouscells,whicharesimplecolumnarwith

tightjunctions

amongthem.Havemucus-containingsecretorygranulesinupperpartofcytoplasm.SecreteinsolublemucuscontaininghighcontentofHCO3-.III.Stomach胃

16Notethesuperficalmucus-secretingepitheliumSurfaceepithelialcellsalsoformanimportantlineofdefenseduetotheirfunctioninmucusproduction,intracellulartightjunctions,whichprotectsmucosafrombeingerodedbyacid(pH=0.9~1.5)andenzymesinthelumenofstomach.

17Regionsofthestomachandtheirhistologicalstructure2.LaminapropriacomposedofLCT,Threetypesofglandscanbeidentified:

gastricorfundicgland胃底腺,

locatedoverthebodyandfundusofthestomach;

cardiacglands贲门腺,

locatednearthecardiacorfice,

and

pyloricglands幽门腺inthepyloricregion.18Eachofgastricglandsisdividedintoaneck、bodyandabaseportionandopensatgastricpit,andcontains5typesofcells:Thelaminaproperiaofthefundusandbodyisfilledwithbranched,tubulargastric(fundic)glands胃底腺,threetosevenofwhichopenintothebottomofeachgastricpit胃小凹.19图10胃底腺模式图胃小凹20a.chief(zymogenic)cells主细胞:predominateintheglandbases.Have

basophilicbase

cytoplasmandapical

cytoplasmcontainingsecretorygranules.胞质基部强嗜碱性，顶部有酶原颗粒21Photomicrographofthebasalportionofthegastricglandinthefundus.Chifecellshowredsecretorygranulesintheircytoplasm.22apicalmicrovilli.Thesecretorygranulesaremembrane-boundAsupranuclearGolgicomplexcontainsmitochondriaandtoughendoplasmicreticulum(RER)withfewribsomesinthebasalcytoplasm.EM:FunctionofChifecell:Secrete

inactive

pepsinogen胃蛋白酶原.23b.parietal(oxyntic)cells:壁细胞presentmainlyattheupperpartoftheglands.Larger,eachofthemcontains1~2nuclei.

Strongacidophiliccytoplasm嗜酸性24

Thecellmembraneinvaginationsandtheirsurrounding

SER

constitutethe

tubulovesicularsystem微管泡系统(Restingstate)←→

Intracellularcanaliculi细胞内分泌小管linedby

microvilli(Activestate).largenumberof

mitochondria线粒体EM:25Electronmicrographofanactiveparietalcell.Notethemicrovilliprotrudingintotheintracellularcanaliculi细胞内分泌小管andtheabundantmitochondria线粒体.26Compositediagramofaparietalcell,showingtheultrastructuraldifferencesbetweenarestcell(left)andanactivecell(right).Notethatthetubulovescles(TV)inthecytoplasmoftherestingcellfusetoformmicrovilli(MV)thatfilluptheintracellularcanaliculi(IC)27FormationofHCl28Functionoftheparietalcell①ParietalcellsContaincarbonicanhydrase,碳酸酐酶iwhicharenecessaryforParietalcellstoSecretehydrochloricacid盐酸,hydrochloricacidturninactivepepsinogen胃蛋白酶原intoactivepepsin胃蛋白酶.

②secrete

intrinsicfactor内因子toprotectVitB12.ThecomplexofVitB12withintrinsicfactorisabsorbedbypinocytosisintothecellinileum回肠.29c.mucousneckcells:颈粘液细胞Locateattheneckofthegland.Secretesoluble

mucus

thatlinesandprotectstheepithelium.30Photomicrographofmucousneckcellsintercalatedbetweenparietalcells.Theyareirregularinshape,withthenuclusatthebaseofcellandthesecretorygranulesneartheapicalsurface.31图11胃底腺（示壁细胞）内分泌细胞主细胞颈粘液细胞壁细胞32d.endocrinecells:内分泌细胞

Argyrophilic嗜银性.Mainlylocateatthebaseofthegland.Secretepolypeptidecontaininghormonesthatcanregulatethefunctionofdigestivetract.

ECL细胞：分泌组胺，促进壁细胞泌酸D细胞：分泌生长抑素，抑制壁细胞G细胞：位于幽门腺，分泌胃泌素，促进壁细胞泌酸和胃肠粘膜增殖33Theendocrinecellscontain

basal

secretorygranules

andcanbedividedinto2types:

*opentype:cellsare

adjacent

tothelumenoftheglands.

*closetype:cellsare

separatedwiththelumenoftheglands.34

e.stemcells干细胞:mainlylocateneartheneckoftheglandbutfewinnumber.Thesecellshaveahighrateofmitosis;someofthemmoveupwardtoreplacethepitandsurfacemucouscells.Otherdaughtercellsmigratemoredeeplyintotheglandsanddifferentiateintoothercellsofthegastricgland.

增殖分化为表面粘液细胞和胃底腺细胞

3.Muscularismucosa:Innercircularandouterlongitudinallayerof

smoothmuscles内环外纵平滑肌

35胃粘膜的自我保护机制粘液-碳酸氢盐屏障（mucous-HCO3-barrier）（1）粘液层：不可溶性粘液凝胶

---隔离上皮与胃蛋白酶

---减慢H+向粘膜扩散（2）表面粘液细胞→HCO3-

→中和H+

→H2CO3碳酸酐酶

CO2

+H2O36B.Submucosa粘膜下层:LCTcontaininglargeblood,lymphvesselsandnerves.C.Muscularis肌层:Innerobliquelayer+middlecircularlayer+externallongitudinallayerof

smoothmuscles.内斜中环外纵Betweenthelayersofsmoothmusclesexistthe

nerveplexus肌间神经丛D.:Serousmembrane.浆膜37Theinnersurfaceofsmallintestinecanbegreatlyenlargedby:*plicaecirculares皱襞:madeupof

mucosaand

submucosa.*villi肠绒毛:madeupof

epithelium

and

laminapropria.*microvilli:associatedonlywiththe

epithelium.IV.Smallintestine:小肠381.Mucosa:粘膜

a.epithelium:上皮composedof4typesofcells.*absorptivecells:吸收细胞simplecolumnarandmostabundant.Cellshaveobscurecellboundariesanddistinctbasalnucleicontainingclearnucleoli.39Apexofeachcellisahomogeneouslayercalledthestriatedborder.纹状缘40Numerousmicrovilli微绒毛(striatedborder)arecoveredbycellcoats(glycocalyx)containingenzymes细胞衣：糖蛋白，含双糖酶、肽酶、胰蛋白酶、胰淀粉酶等Functionofabsorptivecells:Absorption.是消化吸收的部位

41Theinnersurfaceofsmallintestinecanbegreatlyenlargedby:

*plicaecirculares:madeupofmucosaandsubmucosa.X3.*villi:madeupofepitheliumandlaminapropria.X10.*microvilli:associatedonlywiththeepithelium.X20.Togethertheseprocessesareresponsiblefora600-foldincreaseintheintestinalsurface,resultinginatotalareaof200M2.42gobletcells杯状细胞:secretemucus.protectandlubricatetheliningoftheintestine.43endocrinecells内分泌细胞:releasetheirsecretorygranulesandthehomonesmayexertparacrine(local)orendocrine(blood-borne)effects.

44stemcells:干细胞structuresandfunctionsaresimilartothatinstomach.Thesecellsundergomitosisinordertodifferentiatedintoandreplaceothercell-typesofthesmallintestinalgland.位于绒毛根部，小肠腺开口处，较小，柱状；增殖分化，更新上皮细胞45b.laminapropria:固有层CTcontaininglymphatictissues.

protrudesintothelumentogetherwithepitheliumtoformfinger-likevilli.肠绒毛46VilliarecoveredbyepitheliumandcontainfenestratedCap有孔毛细血管networktotransportglucoseandaminoacids,Thelymphvesselsinvilliareknownascentrallacteals中央乳糜管,whichwilltransportlipid.,afewsinglesmoothcells平滑肌responsiblefortherhythmicmovementofvilliwhichareimportantforabsorption.47smallintestinalglands小肠腺48*

smallintestinalglandshavesimilarcellcompositionstothatofepithelium.*Paneth’scells潘氏细胞

:situateatthebottomofglands,withacidophilicsecretorygranulesintheirapexofcytoplasmandrichRERinbasalcytoplasm.SecreteZn2+andlysozymesfordigestingbacteria,49Paneth’scell:Notethelargesecretorygranules50Photographofthebasalportionoftwoglandsofthesmallintestine.Notetheenteroendocrinecell,Paneth’scell,gobletcell,andacellinmitosis.51c.muscularismucosa:innercircularandouterlongitudinallayerofsmoothmuscles.2.Submucosa:LCTcontaininglargeblood,lymphvesselsandnerves.3.Muscularis:Innercircularandouterlongitudinallayerofsmoothmuscles.Thenerveplexus(intramuralganglia)existbetweenthe2layers,responsibleforintestinewring.4.:Serousmembrane.浆膜52Agroupofneuronsandsatellitecellsconstitutingacomponentofthemyenteticpleuxbetweentwosmoothmusclelayers.53.Duodenum

十二指肠

:insubmucosa:isolatedlymphoidnodules.Initssubmucosaexisttheduodenalglands十二指肠腺thatsecretebasicmucus.Villiareleaf-shaped.Fibrousmembraneexistsbehindtheduodenum.54Jejunum空肠

:submucosacontainsisolatedlymphoidnodules.孤立淋巴小结55Ileum回肠:insubmucosaexisttheaggregated

lymphoidnodules集合淋巴小结

knownasPeyer’spatches.Villiarefingerlikeshapes.

Microfoldcells

(Mcells)existintheepitheliumprojectionthatcoversthePeyer’spatches,wherenovillusandglandcanbefound.56Mcellsarespecializedantigenpresentingcellsthatarederivedfromepithelialcells.Mcellhasincompletebasallaminaandlargebasalinvaginationcontainingmacrophagesandlymphocytes,57Mcellscanendocytoseantigensandtransportthemtotheunderlyingmacrophagesandlymphoidcells,whichthenmigratetoothercompartmentsoflymphoidsystem,whereimmuneresponsestoforeignantigensareinitiated.58十二指肠空肠回肠环行皱襞较高、多高、多矮、少小肠绒毛较高、多高、多短、少叶状长指状短锥形杯状细胞较少较多多十二指肠腺有无无淋巴小结孤立孤立集合

小肠三段的比较59Characteristics:Anabsenceofplicaeandvilli无环行皱襞和绒毛Anepitheliumcontaininglargenumbersofgobletcells.杯状细胞非常丰富Well-developed,long,deepandclosely-packedintestinalgland.大肠腺发达，直而密外纵行肌三处增厚形成结肠带Absorptionofwater,formationofthefecalmass,andproductionofmucus.Largeintestine大肠6