妊娠PPT课件.ppt

妊娠ChapterFourGestation,第一节妊娠期LessonOneGestationPeriod妊娠：受精卵在母畜子宫内附植直至分娩的过程叫妊娠。Gestation:Aprocessthatthezygoteenclosedplantindamuterusuntildeliverycalledgestation.妊娠期：最后一次配种直至分娩为止所经历的时间。GestationPeriod:Thetimeexperiencedfromthelastmatingtodelivery.一、动物的妊娠期Partone.Gestationperiodoftheanimal,牛：280天9.5个月水牛：307天10个月Bovine:280days9.5monthsbuffalo:307days10months马：340天11个月马怀骡：330天11个月Horse:340days11monthsmule:330days11months驴：360天12个月羊：150天5个月Neddy:360days12monthssheep:150days5months猪：114天3个月狗：62天2个月Swein:114days3monthsDog:62days2months猫：58天2个月兔：30天1个月Cat:58days2monthsHare:30days1months怀孕期简易推算法Simplemethodsofestimatingpregnancy牛：配种月份减3，配种日期加10Bovine:themattingmonthdecrease3,themattingdate羊：加5，减2sheep:add5，decrease2猪：加4，减10Swein:add4，decrease10马：减1，加10Horse:decrease1，add10,二、影响妊娠期的因素Parttwo.Influencefactorsofgestation（一）遗传因素SectionOne.Geneticfactor（二）胎儿数目和性别因素SectionTwo.Fetalnumberandgenderfactors多胎怀胎数少时，妊娠期变长WhentheMultiplebirthsnumberisfew,pregnantgestationalgrowlonger单胎怀双胎，胎儿为雌性，青年母畜比老龄母畜妊娠期缩短。Ifthemonotocousanimalhadtwinsandthefetusisfemale,thegestationofyoungfemalelivestockisshorterthantheoldfemalelivestocks.（三）营养水平及疾病因素SectionThree.Nutritionlevelanddiseasefactors1.使妊娠期缩短的因素1.Factorsmakegestationshorten营养不良、慢性疾病、强应激。Malnutrition,chronicdiseasesandstrongstress.,2.使妊娠期延长的因素2.Factorsmakegestationlonger1）维生素A不足;1)vitaminAdeficiency;2）连续注射大剂量的孕激素；2)continuousinjectionhigh-doseprogestationalhormone;3）缺碘；3)lackofiodine;4）致畸植物误食。4)teratogenicplantswallowed.三、胎儿数目Partthree.Fetalnumber单胎动物：牛、马、绵羊、山羊Monotocousanimals:bovine,horses,sheep,goats多胎动物：猪、犬、猫Polytocousanimals:pigs,dogs,cats,第二节母体的妊娠识别LessonTwoMaternalrecognitionofpregnancy,一、妊娠识别Partone.Recognitionofpregnancy胚胎与母体子宫从免疫学、细胞生物学、内分泌学等方面相互作用的过程。Aprocessofembryosandthematernaluterusinteractfromimmunology,cellbiologyandendocrinologyaspects.二、妊娠建立Parttwo.Establishofpregnancy继妊娠识别后，母子产生信息和物质交换，妊娠得以维持的现象。Aphenomenonthattheinformationandmaterialexchangefrommotherandgenerateafterrecognitionofpregnancywhichmakesthepregnancymaintained.维持妊娠的主要激素是孕酮，来源于黄体和胎盘。Themainlyhormoneformaintainingthepregnancyisprogesterone,whichoriginatefromcorpusluteumandtheplacenta.,三、妊娠识别与建立的时间Partthree.Thetimeofrecognitionandestablishofpregnancy畜别妊娠识别妊娠建立genderoflivestockrecognitionofpregnancyestablishofpregnancy牛16-17d18-22dbovine16-17d18-22d羊12-13d16dsheep12-13d16d猪12d18dpig12d18d马14-16d36-38dhorse14-16d36-38d,四、动物妊娠识别机理PartFour.Mechanismofrecognitionofanimalpregnancy（一）反刍动物SectionOne.Ruminantanimals滋养层蛋白-1（IFN-，interferon-)通过抑制PGs分泌、OT和E受体合成，促进黄体孕酮的分泌，维持妊娠。Trophoblasticprotein-1(IFN-,interferon-)byinhibitingsecretionofPGsandsynthesisofOTandEreceptor,promotingsecretionofcorpusluteumprogesteronetomaintainpregnancy.（二）猪SectionTwo.Pigs滋养外胚层产生雌二醇和雌酮，转变成硫酸雌酮，使子宫内膜PGs合成减少，并阻止其进入子宫静脉，黄体得以维持。Nourishoutsidemesodermproduceoestrogenandfemaleketones,thenchangethemintosulfuricacidfemaleketones,makethesynthesisofendometrialPGsdecreasesandpreventsitintotheuterusvein,socorpusluteinismaintained.,（三）马SectionThree.Horses与猪相似。Similartothepig.（四）灵长类SectionFour.Primates囊胚的合胞体滋养层产生hCG，抑制溶黄物质的作用。ThesyncytialtrophoblastofblastosphereproducehCG,restrainthefunctionofthesubstancethatdissolveCorpusluteum.hCG是在排卵后7-10天可以从血浆中测出，因此可用作早孕诊断。hCGcanbemeasuredfromplasmain7to10daysafterovulation,soitcanbeusedtodiagnosingearlypregnancies.,第三节胚胎发育和胚泡附植LessonThreeEmbryonicdevelopmentandgerminalvesicleimplantation怀孕是精、卵受精发育成为新的个体起，到从母体子宫中娩出这段时间。需经过卵裂、形成囊胚、胚泡、胚胎着床，建立胎盘系统，最后形成完整的胎儿等一系列发育过程。Pregnancyisthetimestartfromthespermandovumarefertilizedtodevelopintoanewindividual,endatitdeliveredfromtheuterusofmatrix.Needtopasscleavage,formingblastocysts,germinalvesicle,embryoimplantation,establishtheplacentasystem,eventuallyformingcompletefetusandsoonaseriesofdevelopmentprocess.,一、胚胎早期发育PartOne.Earlyembryonicdevelopment,1卵裂球：1.blastomere合子形成后若干天内连续进行的间接分裂，称为卵裂。这时的胚胎称卵裂球。（见图）cleavageisthecontinuationofindirectsplitinseveraldaysafterzygoteformed.theembryosinthistimenamedblastomere.(chart)合子一边沿输卵管下移，一边开始分裂。Azygotemovedownalongthetubal,andbegantosplit.2桑椹胚：2.morula当卵子分裂为1632个细胞时，细胞形成一团形，很象桑椹故称。但仍在透明带包围之中。Whenovumsplitsinto16-32cells,cellsformingagroupform,muchlikethemulberrythereforecallsmorula.Butstillinsurroundedbysheertape.,图7小鼠附植前胚胎发育(引自MH.Kaufman,1995；陈大元,2000)Figure7miceembryonicdevelopmentbeforeimplanted(AccordingtoMH.Kaufman,1995;DayuanChen,2000).,3囊胚：3.blastosphere当桑椹胚中央出现空泡时，细胞出现分化：Whenemptybubbleappearsinthecentralofmorula,cellsbegantodifferentiation:外围：较小的细胞，含有吞噬细胞，称之“滋养层”细胞，是以后形成胎衣的部分。Peripheral:smallercells,containingphagocyticcells,calledthetrophoblasticcells,whichisformedpartofafterbirthlateron.内团：较大的细胞，称“胚结”，是以后形成胚胎的原始部分。Withingroup:largercells,calledembryotie,whichisformedtheoriginalpartofembryoslateron.,这种大小细胞的分化，始于16个细胞。也就是说8胞期之前细胞的分化所造成的异质性不明显，此时的任何一个细胞，通过胚胎分割均可形成一个独立的个体。16个细胞之后，细胞的异质性越来越明显，形成不同功能的细胞群。Thissizecelldifferentiationbeganin16cells.Thatistosaythatcelldifferentiationcausedheterogeneityisnotobviousbefore8cellperiod,atanyoneofthecellsinthistime,allcanformaseparateindividualsthroughtheembryonicsegmentation.After16cells,theheterogeneityismoreandmoreobvious,andformingadifferentfunctiongroupofcells.,4胚泡：4.germinalvesicle:囊胚的继续发育，内部的空泡充满液体，并不断增加，最后突破透明带，透明带消失，此时囊胚就变成了透明的泡状。Theblastospherecontinuedtodevelop,internalvacuolefilledwithfluid,andescalation,finallyitbreakthetransparentbelt,andtransparentbeltdisappear,nowblastospherebecomesatransparentbubbly.透明带消失后，胚泡仍在子宫中游离，通过吸收子宫乳中的营养而成活。野生动物由于野外条件不同，胚泡游离时间差异很大，决定了怀孕期长短。如水貂（37-91天）。afterTransparentbeltdisappeared,agerminalvesicleisstillfreeintheuterus,throughabsorbingnutritionfromthemilk-likeliquidinuterusandsurvive.Duetodifferentfieldconditionsforwildanimals,theirgerminalvesiclehasaverybigdifferenceinfreetime,thisdeterminesthelengthofpregnancy.Likeminks(37-91days).子宫乳成分：上皮细胞碎片、子宫腺分泌物、淋巴球、血球等。ingredientsofUterinemilk:debrisofepithelialcell,secretionofuterinegland,lymphocytes,bloodcell,etc.,5着床：5.nidation胚泡在子宫中的位置固定下来，并开始和子宫内膜发生组织上的联系，称为着床。Thegerminalvesiclespositionintheuteruscometostayandstartorganizationalcontactwithendometrial,calledthenidation.胚泡形成初期，在子宫内呈游离状态，以后一方面由于泡腔内液体增多，胚泡变大，在子宫内的活动受到限制，与子宫上皮的接触变得密切，与母体建立供求关系；另一方面，子宫乳不能满足生长需要而附植下来。着床是一个渐进过程。Atearlyofthegerminalvesicleforming,itisthefreestateintheuterus,Laterononehandbecauseofbubblechamberliquidincreasedandblastocystsgreaten,theactivityisrestrictedintheuterus,andcontactcloselywithuterineepithelia,thenestablishtherelationsbetweensupplyanddemandwithmaternal;Ontheotherhand,uterinemilkcannotsatisfiedtheneedsofgrowthandattachplantdown.Thenidationisagradualprocess.,动物胚胎着床时间ThetimeofAnimalembryonidation,牛：1215天Bovine:12-15days2832天开始到4045天完成；Startat28-32daysaccomplishto40-45days羊：1220天Sheep:12-20days1416天开始到2835天完成；Startat14-16daysaccomplishto28-35days猪：1012天Pig:10-12days1416天开始到2526天完成；Startat14-16daysaccomplishto25-26days马：6065天Horse:60-65days3540天开始到95105天完成；Startat35-40daysaccomplishto95-105days,动物胚胎着床部位ThepositionofAnimalembryonidation,子宫中最有利于发育的地方开始，如牛、羊，多在子宫角基部开始，向中部发展。因这里是子宫中动脉进入子宫的地方，血液供应最为丰富。Startattheplacemostfavorabletothedevelopmentintheuterus,suchasbovineandsheep,muchbeganinthebaseofthecornuauterianddevelopmenttothemiddlepart.Becausehereistheplacethattheuterinearteryentertotheuterus,bloodsupplyisthemostabundant.,第四节胎膜和胎盘LessonFourFetalmembraneandplacenta,一、胎膜PartOne.Fetalmembrane叫胚胎外膜，又叫“胎衣”、“胞衣”、“衣胞”等。Callembryonicoutermembranes,alsocalledafterbirth,secundina,amniaetc.胎膜主要指羊膜、尿膜、绒毛膜，其构造在不同的动物有很大的差异。Fetalmembranemainlyreferstotheamnioticmembrane,urinarymembrane,chorion,itsconstructionhaveagreatdifferenceindifferentanimals.,马、猪胎膜Fetalmembraneofhorsesandpigs,牛、羊胎膜囊Fetalmembranescapsuleofbovineandsheep,1羊膜：是靠近胎儿的一层膜。呈透明状，包围胎儿形成羊膜腔；1.Amnioticmembrane:Itisalayeroffilmnearthefetus.InAtransparentshape,surroundedthefetusandformedamnioticcavity;,2尿膜：可分内外两层，内层与羊膜相粘连，外层与绒膜相粘连；2.Urinarymembrane:Itcanbedividedintotwolevelstheinsideandoutside,theinnerlayerconglutinatedwiththeamnioticmembrane,theouterlayerconglutinatedwiththechorion.3绒毛膜：是胎膜的最外层，表面有绒毛，是形成胎盘的基础。3.Chorion:Itistheoutermostlayerofthefetalmembranes,thesurfaceisvillous,itisthebasisofformingtheplacenta.,4尿膜羊膜：由羊膜和尿膜相互粘连而成。马属动物完整包着胎儿，而在牛、羊、猪胎儿的背侧，无尿膜羊膜。4.Urinaryandamnioticmembrane:Itismutualadhesionbyamnioticmembraneandurinemembrane.Thehorseanimalsiscompletelysurroundthefoetus,whilebovine,sheep,pigssareindorsalofthefoetus,andithasnourinarymembrane.5羊膜绒毛膜：由羊膜和绒毛膜粘连在一起而成。马无此膜。猪的羊膜绒毛膜上密布绒毛，而在牛、羊羊膜绒毛膜上是相对于子宫角弯上或其一侧的一条没有绒毛丛或毛丛很少的区域。5.Amnioticmembraneandchorion:Itisadhesiontogetherbyamnioticmembraneandchorion.Thehorsewithoutthisfilm.Pigsamnioticmembraneandchorionhasdenselyvilli,whileinbovineandsheepsamnioticmembraneandchorionisaareawhathasnofloccusorfloccusrarelywhichwasrelativetotheuteruscorneroritsside.6尿膜绒毛膜：由尿膜和绒毛膜粘连而成。6.Urinarymembraneandchorion:Itisadhesionbyurinarymembraneandchorion.7羊膜腔：含有羊水。7.Amnioticcavity:containamnioticfluid.8.尿膜腔：含有尿水。8.Urinarymembranechamber:containurinaryfluid.,（一）卵黄囊：由内胚层、脏中胚层和滋养层构成。是胚胎发育早期提供营养的器官（起原始胎盘的作用）。SectionOne.Yolksac:Itisconstitutesbytheendoderm,visceralmesodermandtrophoblast.Itistheorgansthatprovidenutritioninearlyofembryonicdevelopment(roleasoriginalplacenta).（二）羊膜囊：羊膜由外胚层（滋养层）和体壁中胚层构成，出现在卵黄囊发育之后，一般在妊娠后13-16天形成。SectionTwo.Amnioticsac:Amnioticmembraneisconstitutesbyectoderm(trophoblastic)andthesomaticmesoderm,whichappearsaftertheyolk-sacdevelopment,andformscommonlyat13-16daysaftergestation.,（三）尿膜囊：尿膜囊壁由中胚层的血管层覆盖在内胚层上构成的。尿膜囊是沿着脐带并靠近卵黄囊由后肠发育而来的一个外囊。SectionThree.Urinarymembranesac:Urinarymembranebursawallisconstitutesbymesodermalvascularlayercoveringtheendoderm.Urinarymembranesacisalongtheumbilicalcordandclosetotheyolk-sacanditisaoutsidesacthatdevelopsbyposteriorintestine.（四）绒毛膜囊：由外胚层和体壁中胚层构成。SectionFour.Chorionicsac:Itisconstitutesbyectodermandsomaticmesoderm.（五）脐带：由卵黄囊残迹和卵黄管和延伸而成，是连接胎儿和胎盘的纽带。SectionFive.Umbilicalcord:Itisextendbytheremnantsofyolk-sacandyolktube,anditislinktoconnectthefetusandplacenta.,二、胎水PartTwo.Placentalfluid,是羊膜腔里的羊水和尿膜腔内的尿水总称。Itisagenerictermsofamnioticfluidintheamnioticcavityandurinaryfluidintheurinarymembranecavity.1羊水1.Amnioticfluid来源：羊膜柱状上皮细胞的分泌物；胎儿唾液腺的分泌物。Sourc:Thesecretionofcolumnarepithelialcellinamnioticmembrane;Thesecretionofthesalivaryglandsinthefetus.颜色：透明粘液状，后期稍带浊白色。Color:transparentmuciform,latewithslightlyturbidwhite.羊水量：牛：56升马：37升羊:0.41.2升只猪：40150毫升只Contentofamnioticfluid:Bovine:5-6litresHorse:3-7litersSheep:0.4-1.2litres/onlyPig:40-150milliliter/only,成分：Ingredients:混有脱落细毛，上皮，灰白色的胎饼（猪没有）。Mixwithfalloffsoftfur,epithelium,gray-whiteembryocake(pigsdonothavethem).含有微量激素，包括PRL、OT。Containtracesofhormones,includingPRL,OT.蛋白酶、淀粉酶、脂解酶。Protease,amylase,lipidsolutionenzymes.蛋白质、果糖、脂肪、盐类。Protein,fructose,fat,salt.,2尿水2.Urinaryfluid来源：膜柱状上皮细胞分泌胎儿尿液（在胚胎的脐孔和脐带逐渐形成时，尿膜腔借脐尿管与膀胱相通，脐尿管也包括在脐带内）Sourc:Secretedbycolumnarepithelialcell;Thefetalurine(whentheumbilicalholeandumbilicalcordisgraduallyformedintheembryo,urinarymembranecavityisinterlinkedwithbladderthroughurachus,andurachusisalsoincludedinumbilicalcord).颜色：尿色Color:Urinarycolor含量：牛：415升马：818升羊：0.51.5升只猪：100240亳升只Content:Bovine:4-15litresHorse:8-18litersSheep:0.5-1.5litres/onlyPig:100-240retainedlitres/only成分：白蛋白、果糖、尿素Ingredients:albumin,fructose,urea,3胎水的作用PartThree.Theeffectofplacentalfluid缓冲作用：使胎儿的身体各部位受压均匀，不致造成畸形。Bufferaction:makeeachpartsofthefetalbodypressureevenly,withoutcausingdeformity.缓和子宫外来压迫、撞击：也可以防止一部分胎盘、子宫壁及脐带受到胎儿压迫，而使血液供给障碍。Easeforeignoppressionandbumpofuterine:alsocanpreventpartofoppressionthatplacenta,uterinewallandumbilicalcordsufferfromfetus,andmakeobstaclesofthebloodsupply.羊水可以防止胎儿与周围组织的粘连。Amnioticfluidcanpreventtheadhesionofthefetusandthesurroundingtissue.分娩时，子宫壁的收缩，可将胎水推压到松软的子宫颈管，从而帮助扩大子宫颈管的作用。Whenparturited,theuterinewalliscontracted,anditwillpushpressplacentalfluidtoloosecervicalcanal,thushelpexpandtheeffectofcervicalcanal.天然润滑剂作用：以利胎儿产出。Effectofnaturallubricants:easytothefetaloutput.,三、胎盘PartThree.Placenta,胎盘通常指尿膜绒毛膜和子宫粘膜发生联系所形成的构造。Placentausuallyreferstothestructurethatformedbythecontactsofurinarymembrane,chorinandtheuterinemucosa.分：胎儿胎盘尿膜绒毛膜的绒毛部分母体胎盘子宫粘膜部分Divideinto:fetalplacentathevillipartofurinarymembraneandchorion.Maternalplacentathepartofuterinemucosa各自分布自己的血管到自己的胎盘部分，并不直接相通。Theydistributedtheirownbloodvesselstotheirownplacentalpart,andnotdirectlyinterlinked.,（一）胎盘的分类SectionOne.Classifyofplacenta,1按照形态分1.Accordingtotheform（1）弥散型胎盘(1)Diffuseplacenta整个尿膜绒毛膜表面均覆盖有绒毛，绒毛伸入子宫内膜腺窝形成胎盘。电镜下,绒毛滋养层上皮细胞核成圆形,核仁大。粗面内质网发达，线粒体丰富。Thewholesurfaceofurinarymembraneandchorionarecoveredwithfluff,andthefluffstretchintoendometrialglandularnestandformedtheplacenta.Underelectronmicroscopy,fluffytrophoblasticepithelialcellsnucleusisroundnessandnucleoliisbig.Roughendoplasmicreticulumisdevelopedandmitochondriaisrich.代表动物:猪、马、骆驼、鲸、海豚等。Representativeanimal:pigs,horses,camels,whales,dolphins,etc.,特点：绒毛和腺窝联系虽是紧密的，但不牢固，绒毛在分离时，不牵连子宫粘膜。Features:Thoughthecontactofvilliandglandularnestisclosely,itisnotfirm.Whenthevilliisinseparation,itdontinvolveduterinemucosa.故：较易发生流产，尤在怀孕早期；分娩时，绒毛膜易脱离，如果胎儿排出缓慢，易发生窒息；胎儿排出快，很少发生胎衣不下。So:Itismoreeasilyhappentoabortespeciallyinearlypregnancy;Whenparturited,chorioniseasilytobreakaway.Ifthefetusexpulsedslowly,itiseasilyhappentostifle;Ifthefetusexpulsedfast,itseldomoccursretentionofafterbirth.,（2）子叶型胎盘(2)Cotyledonstypeplacenta,子宫粘膜上只有子宫阜部分与相应的绒毛发生联系。尿膜绒毛上的绒毛亦分别集中形成许多绒毛丛（形成胎儿子叶）。Itwasonlyuterinepartcontactswiththecorrespondingvilliontheuterinemucosa.Thevilliontheurinarymembranearealsoonthecentralizedandformsmanyvilliplexus(formedthefetalcotyledons).无论牛或羊，子叶之外的区域不与绒毛发生任何联系（联系则为病理状态）。Whetherbovineorsheep,theareasoutsidecotyledonshasnotanycontactwithvilli(Ifcontact,itispathologicalstatus).,电镜下，绒毛表面细胞呈柱状/不规则形，核球形，核仁大，细胞游离面有微绒毛。巨细胞体积大，核仁明显，胞质丰富，可分泌绒毛促性腺激素。Underelectronmicroscopy,fluffysurfacecellsarecolumnarorirregularform,nuclearisspherical,nucleoliisbig,thefreesurfaceofthecellshavemicrovilli.Giantcellhasbigvolumeandnucleoliisobvious,cytoplasmisrich,itcansecretefluffygonadotropins.代表动物：牛、羊属于此类。Representativeanimal:bovineandsheeparebelongtothiskind.,子叶型胎盘的特点Thecharacteristicsofthecotyledonstypeplacenta,流产要比弥散型胎盘发生少；Ithaslessabortionthandiffuseplacenta;联系紧密，产程长也不会造成缺氧而发生窒息；Therelationisclosely,soifthestagesoflaborislong,itwontbehappennedtostiflecausedbyhypoxia;胎衣排出较慢，胎衣不下的比率较高。Afterbirthexpulsedslowly,sotheratiooftheretentionofafterbirthishigher.,（3）带状胎盘(3)Thezonaryplacenta,胎儿绒毛膜上的绒毛集中于绒毛膜中央在尿膜绒毛膜上形成环带状，子宫内膜上也形成相应的带母体胎盘。Thevilliofthefetalchorionhasfocusedonthecentraofthechorionandformedaringbandingintheurinarymembraneandchorion,anditalsoformedthecorrespondingbandingofthematernalplacentaontheendometria.特点：Characteristics:分娩时母体胎盘组织脱落，子宫血管破裂，故有出血现象。Thehemorrhagewillappearbecausewhenparturition,theplacentatissueabscissfromthematrixandthevesseloftheuterinerupture.代表动物：狗、猫。Representativeanimals:Thedogandcat.,犬带状胎盘zonaryplacentaofdog,（4）盘状胎盘(4)Discoidplacenta,绒毛膜上的绒毛在发育过程中逐渐集中，局限于一圆形区域。（绒毛直接侵入子宫内膜血窦中，毛上皮由细胞滋养层和合胞体滋养层构成）呈盘状，故称盘状胎盘。Thevillusonchorionconcentratetoonecircleareagradullyduringdevelopment.(Thevillusinvadeintoendometriumsinusoiddirectly,theepitheliumcomposedofcytotrophoblastandplasmoditrophoblast)Itlookslikeadisk,thereforecallsdiscoticplacenta.代表动物：见于啮齿类和灵长类动物，如兔、鼠和人。Representativeanimals:Therodentandprimatesuchasrabbits,mouse,andhuman.,2.按母体血液和胎儿血液之间的组织层次分2.Accordingtotheleveloforganizationbetweenthemotherandchild,（1）上皮绒毛膜型由子宫上皮细胞和绒毛膜滋养层细胞接触形成。物质交换经六道屏障:(1)Epithelia-chorialtypeItisformedbythecontactofuterineepithelialcellandchoriontrophoblasts.Tofulfilledtheinterchangeofmaterial,theymustacrosssixbarriers:a.子宫内膜上皮endometrialepithelium.b.子宫内膜结缔组织endometrialconnetivetissuec.子宫血管内皮endometrialvascularepitheliumd.胎儿绒毛膜上皮fetuschorionicepitheliume.绒毛膜间充质（结缔组织）connectivetissuef.绒毛膜血管内皮chorionvascularendothelium代表动物：猪和马。Representativeanimals:Theswineandhorse.,（2）上皮结缔绒毛膜型由子宫结缔组织（子宫上皮在妊娠4个月以后变性消失）和绒毛膜接触形成。物质交换只经过五道屏障.(2)epithelialconnectiveChorionic-typeItisformedbythecontactofuterusconnectivetissue(whichwilldisappearafter4monthgestation)andchorion.Itonlyneedfivebarrierstofinishtheinterchangeofmaterial.代表动物：反刍动物。Representativeanimals:Theruminant（3）内皮绒毛膜型由子宫血管内皮和绒毛接触形成。物质交换经过四道屏障.(3)TheendotheliochorialtypeItisformedbythecontactofendometrialvascularepitheliumandvillus.Theinterchangeofmaterialneedtoacrossfourbarriers.代表动物：犬、猫。Representativeanimals:Thedogandcat（4）血液绒毛膜型胎儿绒毛直接侵入母体血液血池内形成。物质交换只经过三道屏障.(4)Bloodepithelia-chorialtypeFetalcotyledoninvadeintomatrixblooddirectly.Theinterchangeofmaterialonlyneedtoacrossthreebarriers.代表动物：啮齿类和灵长类。Representativeanimals:Therodentandprimate,（二）胎盘的生理作用SectionTwo.Thephysiologicalactionofplacenta,胎盘担负着胎儿的消化、呼吸和排泄器官的作用，而且还有内分泌机能。Theplacentashoulderthefunctionofdigestion,breathing,excretionandalsothatofincretion.1胎盘的隔（屏）障作用：1.Thebarrierfunctionoftheplacenta:母子之间物质交换，通过胎盘，具有选择作用。即除了单纯性弥散作用外，还能加速弥散或主动转运作用。Withthehelpoftheplacenta,motherandchildcanfulfilltheinterchangeofmaterial.Theinterchangeofmaterialisselectivebecauseithasnotonlythediffusionfunctionbutalsotheactivetransportfunction.简单的物质可以直接通过胎盘：水、Nacl、Cu、I、VB和VC等；Thesimplerkindofmattercantransittheplacentadirectly:suchaswater,NaCl,Cu,I,VB,Vcandsoon;,某些物质不能直接通过，须经过生化改造后才能通过：Thefollowingmaterialcannottransittheplacentadirectlywithoutthebiochemicalalterations:脂肪脂肪酸甘油蛋白质氨基酸葡萄糖（母体主要糖类）胎盘转化为果糖（胎儿血糖的7080）。LipidFattyacid+GlycerinProteinAminoacidGlucose(mainlythecarbohydrateinmatrix)transformintofructosethroughplacenta(7080bloodsugaroffetus),逆渗透梯度通过胎盘：母体血液中的浓度明显低于胎儿血液。Transittheplacentareversetheosmosisgradient:Theconcentrationofmaterialinbloodofmatrixismuchlowerthanthatoffetus.如钙、磷，如果饲料中含量太低，母体骨髓中的钙、磷即受损耗，易产生孕畜截瘫；Suchascalciumandphosphorus.Thematrixiseasytohavetheparaplegiabecausethecalciumandphosphorusiseasytobelosedwhenthereisnotenoughcalciumandphosphorusinforage.蛋白质：通过分解为氨基酸，后逆浓度梯度进入胎盘Protein:Afterbeingresolvedintoaminoacid,itransittheplacentareversetheosmosisgradient.不能通过屏障的：VA、VD、VE等脂溶性维生素。Thefollowingfat-solublevitaminsuchasVA,VD,VEisunabletotransittheplacenta.,氧气易通过胎盘进入胎儿，二氧化碳则相反易通过胎盘排出；因为，胎盘pH较低，母体氧化血红蛋白进入胎盘很易离析，胎儿血红蛋白对氧有更大的亲和力。胎儿血液与二氧化碳的亲和力要比母体血液低。Oxygencantransittheplacentaintofetuseasily,carbondioxide,on