消化、呼吸系统的发生.ppt

组织胚胎学课件七年制英文医学班专用,中国医科大学基础医学院组胚英文教学组,Chapter24Developmentofdigestiveandrespiratorysystem,*digestiveandrespiratorysystemderivedfromprimitivegut/foregut/midgut/hindgut-epi.ofdigestiveandrespiratorysystemderivedfromendoderm-CTandMTofdigestiveandrespiratorysystemderivedfromsplanchnicorvisceralmesoderm,1.Developmentofdigestivesystem,1)derivativesofpharyngealpouch-pharyngealpouch:/outpocketingsofendodermalliningoftheprimarypharynx(extendsfromthebuccopharyngealmembranetothetracheobronchialdiverticulum)/5pairs,-derivativesofpharyngealpouch:Firstpharyngealpouch:-distalportion:widenintoasac-likestructure-middleearcavity,thebranchialmembraneformtympanicmembraneoreardrum-proximalpart:remainnarrowtoformthepharyngotympanicorEustachiantube,Secondpharyngealpouch:-distalportion:obliterated-remainingpartproliferateandformprimordiumofthepalatinetonsil,Thirdpharyngealpouch:-dorsalportion:differentiatesintoinferiorparathyroidgland-ventralpart:cellsdifferentiatesandformtwocellcords,fusewitheachotherbehindthethoraxtogiverisetothepromordiumofthethymus,Fourthpharyngealpouch:-dorsalportion:formssuperiorparathyroidgland-ventralportion:degeneratesFifthpharyngealpouch:-givesrisetotheultimobranchialbody,immigrateintothyroidanddifferentiateintoparafollicularcells,*developmentofthyroidgland-thyroidprimordium:bythe4thweek,endodermalproliferationofthefloorofprimitivepharynx,thendescendsinfrontoftheprimitivepharynxasabilobeddiverticulum-thyroglossalduct:anarrowcanalconnectingprimitivepharynxwiththyroidprimordium,bythe6thweek,becomessolidanddisappears.,-foramencaecum:-thyroglossalcystandfistula:acysticremnantofthethyroglossalduct,maybefoundatanypointalongthemigratorypathfollowedbythethyroidgland;sometimesathyroglossalcystisconnectedtotheoutsidebyafistulouscanal,calledthyroglossalfistula,2)developmentofesophagusandstomachdevelopmentofesophagus-derivedfromprimitivegutextendingfromthelaryngotrachealdiverticulumtostomach-withthedescentoftheheartandlungs,itlengthensrapidly-muscularcoat,formedbysurroundingmesenchyme/striatedinuppertwo-thirds/smoothinlowerone-third,developmentofstomach-by4thweek,appearsasafusiformdilationofforegut,-greaterandlessercurvatures:bythe5thweek,posteriorpartofstomachgrowfasterthantheanteriorportion-by7-8thweek,aroundthelongitudinalaxis,thestomachcarriesouta90clockwiserotation,itsleftsidetofaceanterior,-rotationaroundthetransverseaxis,thecaudal(pyloric)endofthestomachmovesupwardandtotheright;thecephalic(cardiac)endmovesdownwardandtotheleft,developmentofintestinea.midgutderivatives:-duodenumformation:/formedbyterminalpartofforegutandthecephalicpartofthemidgut/“C”-shapedventrally,rotatestotheright,-midgutloop:by5thweek,midgutgrowrapidlytoforma“U”-shapedloop,itsapexconnectswithyolksacbywayofthenarrowvitellineduct/cephaliclimb/caudallimb,-physiologicalumbilicalherniation:duringthe6thweek,midgutloopgrowrapidly,entertheumbilicalcoelum-extra-embryoniccoelom(inumbilicalcord),-by6-8thweek,midgutlooprotates90aroundanaxisformedbythesuperiormesentericarteryinacounterclockwisedirection,movecephaliclimbtoright,caudallimbleft,-caecalswelling:aconicaldilationofthecaudallimb,formcaecumandappendix,-by10thweek,midgutloopreturntotheabdominalcavity,simultaneouslyrotates180inacounterclockwisedirection,movecephaliclimbtoleft,caudallimbright,-cephaliclimb:developintojejunumandmostpartofileum,-caudallimb:terminalpartofileum,caecum,appendix,2/3transversecolon,b.hindgutderivatives-giveriseto1/3transversecolon,descendingcolon,sigmoid,-cloaca:dilationofterminalpartofhindgut,connectwithallantois,closedbycloacalmembrane,-urorectalseptum:by6-7thweek,mesenchymabetweenhindgutandallantoisproliferatesandformatransverseridge,dividedthecloacaintourogenitalsinusandanorectalcanal,-urogenitalsinus:ventralportionofcloaca,developsintobladderandurethra-anorectalcanal:dorsalportionofcloaca,developsintorectumanduppersegmentofanaltube,3)developmentofliverandpancreasdevelopmentofliverandgallbladder-hepaticdiverticulum:bybeginningof4thweek,endodermalproliferationofendoftheforegut,-hepaticdiverticulumextendsintotheseptumtransversumanddividesintoalargecephalicandasmallcaudalpart-cephalicpartcellsproliferatetogiverisetohepaticcordandbileduct-cysticdiverticulum(caudalpart):developintogallbladderandcysticduct,-thepairedvitellineveinsandumbilicalveinformhepaticsinusoids-atabout6thweek,bloodstemcellimmigrateintoliverfromyolksac,hemopoiesisbegin,developmentofpancreas-dorsalpancreaticbudandventralpancreaticbud:bytheendof4thweek,arisefromtheendodermofcaudalpartoftheforegut-dorsalpancreas,ventralpancreas:pancreaticbudscellsproliferatetogiverisetoacinusandducts,-theventralpancreasrotatestoright-dorsaldirectionandfusewithdorsalpancreas-theventralpancreasformstheinferiorpartoftheheadofthepancreas;dorsalpancreasformsotherpartofpancreas,-mainpancreaticduct,togetherwiththecommonbileduct,enterstheduodenumatthesiteofthemajorpapilla,4)congenitalmalformationsofthedigestivetractatresiaorstenosisofdigestivetract:causedbyfailureofrecanalizationorimproperrecanalization,mostlyinesophagusandduodenum,congenitalumbilicalhernia:causedbyincompleteclosureofthecentralpartoftheabdominalwall,theviscerareturntotheabdomenbutherniatedagainduringthefetalperiod,umbilicalfistulaandMeckeldiverticulum:-umbilicalfistula:resultsfrompersistenceofapatentvitellineduct,meconiumormucusmaybefoundattheumbilicus-vitellinesinus:resultswhenasmallportionofductremainsandopensontotheskin-vitellinecyst:resultswhenintermediatepatentleaves,-vitellineligament:vitellineductpersistasafibrouscord,willcauseintestinalobstruction-Mcekelsdiverticulum:causedbypersistenceofashorelengthofthevitellineduct,thatremainsattachedtoileum,congenitalaganglionicmegacolon:resultsfromtheabsenceofganglioncelloftheparasympatheticganglia,whichcausefailureofthedistalsegmenttomovetheintestinalcontentsonward,imperforateanus,rectalatresiaandrectalfistula:-imperforateanus:resultsfromfailureruptureofanalmembrane,-rectalatresia:duetoafailureoftheanalpittodevelopordeviationoftheurorectalseptumindorsaldirection-rectalfistula:associatewithanimperforateanus,betweentherectumandthevaginaorurinarybladderorurethra,abnormalrotationoftheintestinalloop:nonrotationorreversedrotationofthemidgutatresiaofthegallbladderandbileducts:resultsfromfailureofvacuolizationoftheepithelialcordsorreopen,annularpancreas:ventralpancreaticbudgiverisetotwobranches,whichrotatetheduodenuminanoppositedirection,theduodenumiscompletelysurroundedbypancreatictissue,2.developmentofrespiratorysystem,1)developmentoflarynx,tracheaandlung-laryngotrachealgroove:bythebeginof4thweek,shallowgroovefromtheventralwalloftheforegutcaudaltothehypobranchialeminence-laryngotrachealdiverticulum:laryngotrachealgroovedeparatedfromforegutbytheesophagotrachealseptum,-lungbud:bytheendof4thweek,laryngotrachealdiverticulumformstwolateraloutpocketings.Bythe5thweek,therightlungbudd