组织学与胚胎学-胚胎学2课件.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Germ disc form and differentiate,胚层的形成和分化,1、,Development of the bilaminar germ disc,（二胚层的形成,2,w）：,(1)二胚层,胚盘,（,bilaminar germ disc),。,上胚层,（,epiblast,）,下胚层（,hypoblast,）,羊膜腔（,amniotic cavity)，,卵黄囊(,yolk sac)。,羊膜腔,上胚层,下胚层,卵黄囊,体蒂,（,body stalk),(3)The formation of the yolk sac（卵黄囊形成）,初级卵黄囊,胚外中胚层的网状组织,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,(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 membrane,2、三胚层的形成(第3周）,(1),The primitive streak appears at the beginning of the third week(,原条的出现,3,w),原条,primitive streak,原结,primitive node,原凹,primitive pit,原沟,primitive groove,口咽膜,胚盘,脊索突,原结,原条,泄殖腔膜,中胚层,(2)The definitive endoderm（,内胚层）,and intraembryonic mesoderm（,胚内中胚层）,form through the primitive streak,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 understood,The fate of gastrulation epiblast cells can be predicted from their site of origin.,Study method:Cell tracing and cell lineage（,细胞系）,studies,(3)The notochord(,脊索),is produced by cells that ingress through the primitive node,Primitive pot(,原结）,The Notochordal process（,脊索突）,the notochordal plate（,脊索板）,the notochord,（脊索),意义：决定胚体中轴,诱导外胚层形成神经板,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：胚胎发育：第一周：植入,第二周：二胚层,第三周：三胚层,第四周：圆柱体,Meningohydroencephalocele(,脑积水脑膜脑突出）,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.,小结：,神经系统、脑垂体、松果体、,皮肤：表皮、附属结构,凹陷上皮：,口、鼻、肛门、外耳道、,膜迷路、角膜上皮、视网膜、晶状体,肾上腺髓质、腮腺上皮,(2),神经嵴,周围神经系统,肾上腺髓质,分化,外胚层分化,(3),表面外胚层,:,皮肤表皮及其附属器,2,、,mesoderm differentiate(,中胚层的分化)：,（,1,）,paraxial mesoderm(,轴旁中胚层)(,somites),体节，,第,5,周全部形成，共,42-44,对，分化为真皮，大部分中轴骨和骨骼肌。,（,2,）,intermediate mesoderm(,间介中胚层),位于体节外侧,，泌尿生殖系统发生的原基。,3,、,Endoderm differentiate(,内胚层的分化)：,随胚体的卷曲，内胚层形成,原始消化管,，,内胚层：,是消化系统、呼吸系统和中耳、甲状腺、,甲状旁腺、扁桃体、胸腺，膀胱和尿道等上皮的原基。,口咽膜,咽囊,前肠,肺芽,中肠,后肠,泄殖腔,围心腔,尿囊管,肛膜,五周人胚,四周人胚,围心腔,咽囊,胃,肝,中肠袢,后肠,肝隙室,五、胚胎外形的建立及演变,1,、胚体的形成,五周鳃弓全，视杯与听泡。,六周手指见，耳廓小苗苗。,七周体伸直，颜面形成了。,八周成人形，肢体头面俏。,三月分男女，四月能打闹。,五月爱运动，胎心可听到。,六月见指甲，皮红显发毛。,七月眼开合，八月睾丸掉。,九月体发福，十月生宝宝。,1名词解释：,Bilaminar germ disc Trilaminar germ disk Primitive streak,Notochord,Neural tube,2.,简述三胚层的形成及分化。,