组织学与胚胎学胚胎学-PPT.pptx

组织学与胚胎学胚胎学体蒂体蒂l(body stalk)(2)The amniotic cavity develops within the epiblast上胚层上胚层下胚层下胚层(3)The formation of the yolk sac(卵黄囊形成)初级卵黄囊初级卵黄囊胚外中胚层得网状组织胚外中胚层得网状组织On days 10 to 11,an acellular extraembryonic reticulum form between Heusers membrane and the cytotrophoblast、下胚层形成次级卵黄囊下胚层形成次级卵黄囊(4)The hypoblast gives rise to the extraembryonic endoderm that lines the primary yolk sac(5)The chorionic cavity is produced in conjunction with the development of the extraembryonic mesoderm(6)The definitive yolk sac is formed by a new wave of cells that migrate from the hypoblast and displace heusers membrane2 2、三胚层得形成、三胚层得形成(第第3 3周周)(1)The primitive streak appears at the beginning of the third week(原条得出现原条得出现,3,3w)w)原条原条 primitive streak原结原结 primitive node原凹原凹 primitive pit 原沟原沟 primitive groove两胚层胚盘背面观两胚层胚盘背面观原条外胚层羊膜切缘口咽膜内胚层口咽膜口咽膜胚盘胚盘脊索突脊索突脊索突脊索突原结原结原条原条泄殖腔膜泄殖腔膜中胚层中胚层Significance:The appearance of the primitive streak establishes the longitudinal axis and thus the bilateral symmetry of the future adult and decide embryo orientation 1、确定了中轴确定了中轴2 2、确定头尾方向、确定头尾方向 3 3、就是胚体得组织中心就是胚体得组织中心(2)The definitive endoderm(内胚层内胚层)and intraembryonic mesoderm(胚内胚内中胚层中胚层)form through the primitive streak12大家应该也有点累了，稍作休息大家有疑问的，可以询问和交流大家有疑问的，可以询问和交流大家有疑问的，可以询问和交流大家有疑问的，可以询问和交流the ectoderm外胚层the mesoderm中胚层definitive endoderm内胚层the epiblast上胚层The primitive streak retreats and disappears,and the caudal eminence gives rise to caudal structures of the body、(15-26day)The mechanics of gastrulation are not well understoodThe fate of gastrulation epiblast cells can be predicted from their site of origin、Study method:Cell tracing and cell lineage(细胞系细胞系)studies(3)The notochord(脊索)is produced by cells that ingress through the primitive nodePrimitive pot(原结原结)The Notochordal The Notochordal process(process(脊索突脊索突)the notochordal the notochordal plate(plate(脊索板脊索板)the notochordthe notochord(脊索脊索)意义意义:决定胚体中轴决定胚体中轴 诱导外胚层形成神经板诱导外胚层形成神经板 椎间盘中髓核。椎间盘中髓核。The ultimate fate of the notochord is debated、Mesoderm is excluded from the buccopharyngeal and cloacal membrances、小结小结:胚胎发育胚胎发育:第一周第一周:植入植入 第二周第二周:二胚层二胚层 第三周第三周:三胚层三胚层 第四周第四周:圆柱体圆柱体四、三胚层得分化四、三胚层得分化1、外胚层得分化、外胚层得分化(1)神经管形成神经管形成:neural plate neural plate 神经板神经板 neural groove neural groove 神经沟神经沟 neural fold neural fold 神经褶神经褶 neural tube neural tube 神经管神经管 脑、脊髓脑、脊髓前神经孔前神经孔 未闭未闭 无脑儿无脑儿后神经孔后神经孔 未闭未闭 脊髓裂脊髓裂 脊柱裂脊柱裂 Meningohydroencephalocele(脑积脑积水脑膜脑突出水脑膜脑突出)This anomaly may form through defective ossification of the occipital bone and probably is not a consequence of defective closure of the neural tube、Headless mice、The development and maintenance of the“head organizing center”requires the expression of the homeobox gene Lim-1、Knock out of Lim-1 results in headless mice、Fig 4-12小结小结:神经系统、脑垂体、松果体、神经系统、脑垂体、松果体、皮肤皮肤:表皮、附属结构表皮、附属结构 凹陷上皮凹陷上皮:口、鼻、肛门、外耳道、口、鼻、肛门、外耳道、膜迷路、角膜上皮、视网膜、晶状体膜迷路、角膜上皮、视网膜、晶状体 肾上腺髓质、腮腺上皮肾上腺髓质、腮腺上皮(2)(2)神经嵴神经嵴 周围神经系统周围神经系统 肾上腺髓质肾上腺髓质 分化外胚层外胚层分化分化(3)表面外胚层表面外胚层:皮肤表皮及其附属器皮肤表皮及其附属器2、mesoderm differentiate(mesoderm differentiate(中胚层得中胚层得分化分化):):(1)paraxial mesoderm(paraxial mesoderm(轴旁中胚层轴旁中胚层)(somites)somites)体节体节,第第5周全部形成周全部形成,共共42-44对对,分化为真皮分化为真皮,大部分中轴骨与骨骼肌。大部分中轴骨与骨骼肌。(2)intermediate mesoderm(intermediate mesoderm(间介中胚层间介中胚层)位于体节外侧位于体节外侧,泌尿生殖系统发生得原泌尿生殖系统发生得原基。基。(3)lateral plate mesoderm(lateral plate mesoderm(侧中胚层侧中胚层)分两层分两层A:Parietal mesoderm(A:Parietal mesoderm(体壁中胚层体壁中胚层):):分化分化为体壁得肌肉、结缔组织、浆膜壁层。为体壁得肌肉、结缔组织、浆膜壁层。B:Ventral mesoderm(B:Ventral mesoderm(脏壁中胚层脏壁中胚层):分化分化为内脏平滑肌、结缔组织与浆膜脏层。为内脏平滑肌、结缔组织与浆膜脏层。胚内体腔胚内体腔:形成体腔。形成体腔。体节体节21天天3、Endoderm differentiate(Endoderm differentiate(内胚层得内胚层得分化分化):):随胚体得卷曲随胚体得卷曲,内胚层形成原始消化管内胚层形成原始消化管,内胚层内胚层:就是消化系统、呼吸系统与中耳、甲状腺、就是消化系统、呼吸系统与中耳、甲状腺、甲状旁腺、甲状旁腺、扁桃体、胸腺扁桃体、胸腺,膀胱与尿道等上皮得原基。膀胱与尿道等上皮得原基。口咽膜口咽膜咽囊咽囊前肠前肠肺芽肺芽中肠中肠后肠后肠泄殖腔泄殖腔围心腔围心腔尿囊管尿囊管肛膜肛膜五周人胚四周人胚围心腔围心腔咽囊咽囊胃胃肝肝中肠袢中肠袢后肠后肠肝隙室肝隙室五、胚胎外形得建立及演变五、胚胎外形得建立及演变1、胚体得形成、胚体得形成三周三胚层三周三胚层,体节神经兆。体节神经兆。四周圆筒状四周圆筒状,头大尾尖小头大尾尖小,外形似豆芽外形似豆芽,头尾腹侧靠。头尾腹侧靠。神经沟神经沟轴旁中轴旁中胚层胚层间介中间介中胚层胚层 生肾节生肾节体节体节神经褶神经褶体壁体壁中胚层中胚层轴旁中轴旁中胚层胚层神经管神经管脏壁中脏壁中胚层胚层羊膜腔羊膜腔神经板神经板