組織學與胚胎學課件(英文版)

IntroductiontoHumanEmbryology1.WhatisEmbryology？FertilizationInfantNinemonths(266daysor38weekstobeexact)intheuterusZygotePrenatalperiodGestationalperiod1.WhatisEmbryology？FertilizationInfantNinemonths(266daysor38weekstobeexact)intheuterusZygotePrenatalperiodGestationalperiod1.WhatisEmbryology？PrenatalperiodEmbryonicperiodFetalperiod1.WhatisEmbryology？PrenatalperiodEmbryonicperiodFetalperiod1.Itextendsfromfertilizationthrough8weeks2.Thedevelopingindividualiscalledanembryo.1.WhatisEmbryology？PrenatalperiodEmbryonicperiodFetalperiod1.Itextendsfromfertilizationthrough8weeks.2.Thedevelopingindividualiscalledanembryo.1.Itextendsfromweek9untilbirth.2.Thedevelopingindividualiscalledafetus.1.WhatisEmbryology？Embryologyisthestudyoftheformationanddevelopmentoftheembryo(orfetus)fromthemomentofitsinceptionuptothetimewhenitisbornasaninfant.Fertilizationthrough8weeksEachofthefirst3weeksischaracterizedbyspecificdevelopments.Week1startswithfertilizationandextendsthroughthefirstcelldivisionsthatproduceanembryowithonegermlayer.Embryonicperiod2-cellstage8-cellstage4-cellstage

morulaEarlyblastocystLateblastocystFertilizationthrough8weeksEachofthefirst3weeksischaracterizedbyspecificdevelopments.Week1startswithfertilizationandextendsthroughthefirstcelldivisionsthatproduceanembryowithonegermlayer.Week2producestwogermlayers.EmbryonicperiodFertilizationthrough8weeksEachofthefirst3weeksischaracterizedbyspecificdevelopments.Week3producesthreegermlayersandfoldsthoselayersintoarecognizablethreedimensionalbody.EmbryonicperiodFertilizationthrough8weeksEachofthefirst3weeksischaracterizedbyspecificdevelopments.Weeks4through8(month2)aretheperiodoforganogenesis.EmbryonicperiodAllthemajoreventsoforganformationandformationofbodyregionsoccurduringtheperiodoforganogenesis,whichiscompletedintheembryonicperiod.Fertilizationthrough8weeksWeek1anembryowithonegermlayer

Week2twogermlayers

Week3threegermlayersWeeks4through8(month2)organogenesisEmbryonicperiodMonth3tobirth

Themajoreventsthatoccurduringthefetalperiodinvolvegrowthinsize(hypertrophy)oforgansbyrapidincreaseincellnumber(hyperplasia),aswellasbiochemicalandfunctionalmaturation.Maturefunctionalstatusisnotachievedinmostorgansystemsuntilafterbirth.Fetalperiod2.WhyamedicalstudentshouldstudyEmbryology？1.Thissubjecttellsushowtheorgansofthebodydevelop.2.WhyamedicalstudentshouldstudyEmbryology？1.Thissubjecttellsushowtheorgansofthebodydevelop.2.Thisknowledgehelpsustounderstandmanycomplicatedfactsofadultanatomy.MidgutloopCephaliclimbCaudallimbMidgutloopCephaliclimbCaudallimbMidgutloopCephaliclimbCaudallimbCaudallimbSuperiormensentericartery2.WhyamedicalstudentshouldstudyEmbryology？1.Thissubjecttellsushowtheorgansofthebodydevelop.2.Thisknowledgehelpsustounderstandmanycomplicatedfactsofadultanatomy.3.Embryologyhelpsusunderstandwhysomechildrenarebornwithorgansthatareabnormal.Appreciationofthefactorsresponsibleformaldevelopmentassistsusinpreventing,ortreating,suchabnormalities.somemainbranchesofEmbryologyDescriptiveEmbryologyComparativeEmbryologyExperimentalEmbryologyChemicalEmbryologyMolecularEmbryologyReproductiveEngineeringTeratologyThetestisisthemalesexorganormalegonad.Theovaryisthefemalesexorganorgonad.Theyproducehighlyspecializedgametes.Malegametesproducedbythetestisarecalledspermatozoa.

Theprocessiscalledspermatogenesis.Femalegametesproducedbytheovaryarecalledova.Theprocessiscalledoogenesis.Spermatogenesisandoogenesisaretogethercalledgametogenesis.Chromosomes46chromosomesinasomaticcellofhumanThisisreferredtoasthediploid(double)number23chromosomesinagameteofhumanThisiscalledthehaploid(half)number23pairsofhomologouschromosomesonechromosomeofeachpairisderivedfromthemotherandtheotherfromthefatherChromosomestructureIndividualchromosomesdifferfromoneanotherintotallength,intherelativelengthofthetwoarmsandinvariousothercharacteristics.Classificationofchromosomesinthiswayiscalled

karyotyping.Karyotypingmakesitpossibleforustodetectabnormalitiesinchromosomenumberorinindividualchromosomes.SignificanceofChromosomesThetremendousvolumeofinformationisstoredwithinthechromosomesofeachcell.chromosomescontrolthedevelopmentandfunctioningofcells,bydeterminingwhattypesofproteinswillbesynthesizedwithinthem.Chromotidismadeuppredominantlyofanucleicacidcalleddeoxyribonucleicacid(orDNA),andallinformationisstoredinmoleculesofthissubstance.CellDivisionMultiplicationofcellstakesplacebydivisionofpre-existingcells.Celldivisionoccursthroughoutthelife.Thegeneticinformationwillbepassedontothedaughtercellsresultingfromthedivision.Twokindsofcelldivision:mitosis,meiosis.MitosisMeiosisSomaticcellsGametogenesisThenumberofchromosomesandthegeneticcontentinthedaughtercellsisidenticaltothoseinthemothercellThenumberofchromosomesinthedaughtercellsisreducedtohalfthenormalnumberThegeneticinformationinthevariousgametesproducedisnotidenticalMitosisTheperiodduringwhichthecellisactivelydividingis

thephaseofmitosis.Theperiodbetweentwosuccessivedivisionsiscalledtheinterphase.Mitosisisconventionallydividedintoanumberofstagescalledprophase,metaphase,anaphaseand

telophase.Ploiddesignatesthenumberofhomologouschromosomespresent:diploid(double),haploid(single).1N,2N,4Nrefertothenumberofcopiesofchromatidspresent,where1N=23.chromosomeschromatidsA462NB,C,D,E464NF46pairs4NG(onedaughtercell)462NMeiosismeiosisconsistsoftwosuccessivedivisionscalledthefirstandsecondmeioticdivisions.Duringtheinterphaseprecedingthefirstdivision,duplicationoftheDNAcontentofchromosomestakesplaceasinmitosis.Theprophaseofthefirstmeioticdivisionisprolongedandisusuallydividedintoanumberofstages.OogenesisandSpermatogenesisQuestions1.Describethestructureofatypicalchromosome？2.Accordingtothedifferencesinthelengthofthetwoarmsofeachchromatid,howmanytypesofchromosomesarethere?3.What’sthedifferencesbetweenmitosisandmeiosis?4.Theprocessofspermatogenesisandoogenesis.5.PreviewfertilizationandformationofgermlayersZonapellucidaGranulosacellsSecondaryoocyteindivisionPrimaryoocyteindivisionSecondaryoocyteandpolarbody1PolarbodyindivisionOvarianCycleAtpuberty,thefemalebeginstoundergoregularmonthlycycles.ThesesexualcyclesarecontrolledbytheHPG(Hypothalamus-Pituitary-Gonad)axis.GnRH,Gonadotropin,follicle-stimulatinghormone(FSH)luteinizinghormone(LH)/ICSH

Atthebeginningofeachovariancycle,15to20primary(preantral)folliclesarestimulatedtogrowundertheinfluenceofFSH.Undernormalconditions,onlyoneofthesefolliclesreachesfullmaturity,andonlyoneoocyteisdischarged;theothersdegenerateandbecomeatretic.Whenafolliclebecomesatretic,theoocyteandsurroundingfollicularcellsdegenerateandarereplacedbyconnectivetissue,formingtheinterstitialgland(corpusatreticum).

Granulosaandthecalcellsproduceestrogensthat(a)causetheuterineendometriumtoenterthefollicularorproliferativephase;(b)causethinningofthecervicalmucustoallowpassageofsperm;(c)stimulatethepituitaryglandtosecreteLH.Atmid-cycle,thereisanLHsurgethat(a)causesoocytestocompletemeiosisIandinitiatemeiosisII;(b)stimulatesproductionofprogesteronebyfollicularstromalcells(luteinization);(c)causesfollicularruptureandovulation.OvulationTheprocessthatthematurefolliclerupturesandthesecondaryoocyte,zonapellucida,coronaradiataandfollicularfluidarereleasedfromtheovaryiscalled～.Time:ovulationtakesplaceataboutthemiddleofthecycle.OvulationThefateofthesecondaryoocyteafterovulationDegenerationundergoesifnofertilizationoccurs.Iffertilizationhappens，thesecondmeiosisisfinished,andtheovumforms.FATE1FATE2Afterovulation,granulosacellsremaininginthewalloftherupturedfollicle,togetherwithcellsfromthethecainterna,arevascularizedbysurroundingvessels.UndertheinfluenceofLH,thesecellsdevelopayellowishpigmentandchangeintolutealcells,

whichformthecorpusluteumCorpusLuteumGRANULOSALUTEINCELLSTHECALUTEINCELLS

Cellsofcorpusluteum

GranulosaluteinC：progesteroneandrelaxinThecaluteinC：estrogenProgesterone,togetherwithestrogen,causestheuterinemucosatoentertheprogestational

orsecretorystage

inpreparationforimplantationoftheembryo.FateofcorpusluteumCorpusluteumofmenstruation

→corpusalbicansCorpusluteumofpregnancy→corpusalbicansCorpusalbicansRelationoffimbriaeandovary.Fimbriaecollecttheoocyteandsweepitintotheuterinetube.Fertilization---Fertilizationistheprocessinwhichthemaleandfemalegametes(spermandovum)unitetogiverisetoazygote.---place:intheampullaoftheuterinetubeConditionsoffertilization:1)

maturationofoocyte2)maturationofspermatozoa:2-3weeksintheductusepididymisacquiresomemotilitydecapacitationfactor:existinepididymis,toinhibitthereleaseofacrosomeenzymes

capacitationfactor:secretedbyepi.cellsofoviduct,capacityofreleasingacrosomeenzymescapacitationofspermatozoa

3)qualityandquantityofspermatozoa:normal:3-4ml,100,000,000/ml,abnormal:<1.5ml;or<10,000,000/ml;abnormalsperm>30%;mobility<70%4)

meetingofspermandovumsperm:<4daysovum:<2daysprocessesoffertilization:

1)

acrosomereaction:A.hyaluronicacidase:dissolvecoronaradiataB.interactwithZP3(receptorglycoprotein,existinzonapellucida)molecules,releaseacrosin:dissolvezonapellucidathensomespermatozoaenterperivitellinespace

2)onlyonespermatozoonfusewithmembraneoftheovum:nucleusentercytoplasmoftheovum

corticalreaction:corticalgranules(locatedincytoplasmofovum)arereleasedintoperivitellinespace,andcausezonareaction:changeofZP3moleculesinzonapellucide3)formationofzygote(fertilizedovum)A.secondarymeiosiscomplete:formsecondpolarbodyB.malepronucleusfusewithfemalepronucleustorestore2Nchromosomessignificanceoffertilization:1)anewlifebegin(initiationofcleavage)2)restorationofthediploidnumberofchromosomes3)determinationofthesexofthenewindividual:ovum(22+X)+X-bearingspermatozoon=girlovum(22+X)+Y-bearingspermatozoon=boyBlastocystformation

and

implantation

2-cellstage8-cellstage4-cellstage

morulaEarlyblastocystLateblastocyst1)cleavageandblastocystformation①cleavage:mitosisofthezygote---blastomere:cellsfromcleavage30h:2cells40h:4cells72h:12-16cells–morulaformation②formationofblastocyst:by5thday,blastomerereachto107,smallspaceappearbetweenthemblastocoele:filledwithliquidtrophoblastinnercellmass(embryoblast

)polartrophoblastinnercellmassblastocoeletrophoblastZonapellucidaPolartrophoblastEarlyblastocystlateblastocyst

2)

Implantationdefinition:theprocessinwhichtheblastocystisembeddedinendometriumoftheuterustime:beginonthe5th–6thday;finishonthe11th–12thdayplace:fundusandbodyofuterus

process:zonapellucidedisappear→polartrophoblasttouchtheendometrium→secreteproteolytase→dissolvetheendothelium→embeddedintoendometrium→coagulationplugsealthespace*trophoblastbecomeintotwolayerswhenblastocystisembeddingintoendometriumsyncytiotrophoblastcytotrophoblastendometriumColumnarepitheliumA7.5-dayhumanblastocyst,partiallyembeddedintheendometrialstroma.Thetrophoblastconsistsofaninnerlayerwithmononuclearcells,thecytotrophoblast,andanouterlayerwithoutdistinctcellboundaries,thesyncytiotrophoblast.Theembryoblastisformedbytheectodermandendoderm.Theamnioticcavityappearsasasmallcleft.ectodermendodermdecidualresponseofendometriumstromacell→predecidualcell→decidualcell(cellbecomelargerandrichinglycogenandlipiddroplets)endometrium→decidua:deciduabasalisdeciduacapsularisdeciduaparietalisConditionsofimplantation:

-endometriumisinsecretoryphase

-morulareachthecavityofuterusontime

-zonapellucidedisappearsintimeRelationshipbetweentheembryoandtheendometriumDeciduacapsularisembryovaginacervixUterinecavityDeciduaparietalisDeciduabasalisFormationanddifferentiationoftrilaminargermdisc1.formationofepiblastandhypoblast

:

Bythe8thday,theinnercellmassdifferentiatesintotwolayersofcells

epiblast(columnar)hypoblast(cuboidal)bilaminargermdiscAmnioniccavityepiblasthypoblastBilaminargermdisc---epiblast:primaryectodermamnioticcavity:amnioticfluidroof:amniogeniccellsfloor:epiblast---hypoblast:primaryendodermhypoblast→Heuser’smembrane→primaryyolksacAmnioniccavityepiblasthypoblastBilaminargermdiscExtra-embryonicmesodermPrimaryyolksacBodystalkExtra-embryoniccavityExtra-embryonicmesodermPrimaryyolksacsecondaryyolksac

extra-embryonicmesoderm→extra-embryoniccavity(chorioniccavity)--viscerallayer--parietallayer/secondaryyolksac:yolksac---bodystalk(connectingstalk):formedbyextra-embryonicmesoderm2.formationofmesoderm:intheearlyofthe3rdweek---primitivestreak:cellsofepiblastproliferatetoformalongitudinalarrangedcellcord*determinationofheadandtailofgermdisc2.formationofmesoderm:intheearlyofthe3rdweek---primitivestreak---primitivenode(primitiveknot)2.formationofmesoderm:intheearlyofthe3rdweek---primitivestreak:---primitivenode(primitiveknot)---primitivepit(blastopore)---mesoderm:intra-embryonicmesoderm---endoderm:hypoblastcellsarereplacedbyepiblastcells---ectoderm:epiblastchangedthenameintoectoderm

bytheendofthe3rdweek

trilaminargermdisc:endoderm+mesoderm+ectoderm

---headprocess→notochordaltube→notochord---buccopharyngealmembrane---cloacalmembranenotochord3.differentiationoftrilaminargermdisc4th–8thweeks---differentiation:samecellswhichareprimordialandinmuturedifferentiateintodifferentcellswhichhavespecificstructureandfunction---induction:sometissueseffectthedifferentiation,anddeterminethedifferentiatingorientationofanothertissue(1)

differentiationofectoderm:from18th–19thdays---neuralplate:neuro-epithelium(neuralectoderm):pseudostratifiedcolumnarepi.neuralplateNotochord(1)

differentiationofectoderm:from18th–19thdays---neuralplate---neuralgroove---neuralfoldNeuralgrooveNotochordNeuraltubeAnteriorandposteriorneuropores---neuraltube:→CNS/anteriorneuropore:closedby25thdays/posteriorneuropore:closedby27thdays---neuraltube:CNS---neuralcrest:twolinesofcellcords→ganglions(2)differentiationofmesoderm:17thdayNeuralgrooveIntermediatemesodermLateralmesoderm

paraxialMesodermendoderm---paraxialmesodermsomite:20thdays,3pairs/perday,42-44pairsbytheendof5thweeks-sclerotome:→bone,cartilage-dermatome:→dermisandhypodermis-myotome:→skeletalmuscleIntermediatemesodermNeuralcanalSomiteendodermIntraembryoniccavity---intermediatemesoderm:→kidneyandreproductivesystem---lateralmesoderm:Intra-embryoniccoelom:→bodycavityparietalorsomaticmesoderm:→muscle,CT,parietallayerofpleura,peritoneumandpericardiumvisceralorsplanchnicmesoderm:→muscle,CTofdigestivetract,viscerallayerofpleura,peritoneumandpericardiumParietalmesodermvisceralmesodermIntra-embryoniccavity3.differentiationofendoderm:

primitivegut:→digestive,respiratoryandurinarysystem

foregutmidguthindgutCloacalmembraneoropharyngealmembrane1.Embryonicperiodis

A.fromfertilizationtotheendofweek2

B.fromfertilizationtotheendofweek8

C.fromweek3totheendofweek8D.fromweek5totheendofweek8E.fromweek9untilbirth2.Howlongwillanindividualstayintheuterusofitsmother?

A.18weeks

B.28weeks

C.38weeks

D.48weeks

E.58weeksBC3.Whatispenetratedbyaspermatozoonduringtheprocessoffertilization

A.oogonium

B.primaryoocyte

C.secondaryoocyteD.primaryfollicleE.primordialfollicle4.Whichproteinisreceptorofspermatozoaonthezonapellucida?

A.ZP1

B.ZP2

C.ZP3

D.ZP4

E.ZP5C

C5.Thetimeofimplantationis

A.from1st-2nddayto7th-8thday

B.from3rd-4thdayto9th-10thday

C.from5th-6thdayto11th-12thdayD.from7th-8thdayto13th-14thdayE.from9th-10thdayto15th-16thday6.Whichstructureisnotbelongtoearlyblastocyst?

A.trophoblast

B.zonapellucida

C.innercellmass

D.blastocoele

E.endodermC

E

7.Whichisnotcorrectaboutimplantation

A.blastocystwillbeimbeddedintheendomytrium

B.zonapellucidadisappears

C.polartrophoblastsecretesproteinaseD.endomytriumisinproliferativephaseE.thereisacorpusluteumofpregnancyintheovary8.Themostcommonpositionofimplantationis

A.mucusofuterinetube

B.mucusofampullaryportionofuterinetube

C.ovary

D.mucusofcervixofuteru

E.mucusofbodyofuterusD

E

Fetalmembranesandplacentaareauxiliarystructuresoftheembryoandfetus.Theyhavefunctionsofprotection,nutrition,respirationandexcretion.Someofthemcanproducehormonetomaintainthepregnancy.Aftertheinfantisborn,fetalmembranesandplacentawillseparatefromuterusandbeextrudedoutofbody.ChorionAmnionYolksacAllantois(allantoicdiverticulum)UmbilicalcordFetalmembranes1.chorion:trophoblastextra-embryonicmesoderm

Primaryvilli:acentralcoreofcytotrophoblastcoveredbyalayerofsyncytiotrophoblast.Adoiningvilliareseparatedbyanintervillousspace.cytotrophoblastsyncytiotrophoblastintervillousspaceextra-embryonicmesoderm

capillarybloodvesseldeciduasecondaryvilli:Aninnerlayerextra-embryonicmesoderm

AnintermediatelayercytotrophoblastAnouterlayersyncytiotrophoblastcytotrophoblastsyncytiotrophoblastintervillousspaceextra-embryonicmesoderm

capillarybloodvesseldecidua

tertiaryvilli:arelikesecondaryvilliexceptthatextra-embryonicmesodermdifferentiateintocapillariesandCT.cytotrophoblastsyncytiotrophoblastintervillousspaceextra-embryonicmesoderm

capillarybloodvesseldeciduaformationofcytotrophoblasticshellformationofcytotrophoblasticshellformationofcytotrophoblasticshell2.Yolksac:---bloodisland:primitivebloodcell-derivedfromextra-embryonicmesodermonthewallofyolksac---primordialgermcell:derivedfromendodermofyolksac3.Amnion:---amnioticmembrane:amnioticepi.+extra-embryonicmesoderm---amnioticfluid:/secretedbyamnioticepi./slightbasicfluid:1000-1500ml-polyhydramnios:>2000ml,abnormaldigestivesystemorCNS-oligohydramnios:<500ml,abnormalurinarysystem/function:-intra-environment-protecting-preventingfromadherence-washgermtract4.Allantois(allantoicdiverticulum)

---allantoicA:paired,→umbilicalA---allantoicV:pairedright:degenerateleft:umbilicalV5.Umbilicalcord---cylindricalstructure---surface:amnioticmembrane---cord:mucousCT,umbilicalA,V,yolksacandallantois---40-60cmlong,1.5-2.0cminD--->80cm,or<35cm---thestructurebywhichexchangeofmaterial