组织学与胚胎学胚胎学_课件-体蒂.pdf

组织学与胚胎学胚胎学体蒂 e(body stalk)Actual sizeSyncytiotrophobl astConnecting stal kCytotrophobl astExtraembryonic mesodermTrophobl astic l acuna14-15 daysRemnants of primary yol k sac(exocoel omic cysts)(2)The amniotic cavity develops within the epiblastActual sizeSyncytiotrophobl ast Cytotrophobl ast/Amniotic cavity上胚层Epibl ast-下胚层Hypobl ast一Maternal capil l ary8 days(3)The formation of the yolk sac(卵黄囊 形成)初级卵黄囊On days 10 to 11,an acellular extraembryonic reticulum form between Heusers membrane and the cytotrophoblast胚外中胚层得网状组织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 heuser9s membrane 2、三胚层得形成（第3周）（1）The primitive streak appears at the beginning of the third week（原条得出现,3w）原条 primitive streak 原结 primitive node原凹 primitive pit原沟 primitive groove两胚层胚盘背面观外胚层 羊膜切缘口咽膜管索实中胚层原结原条I泄殖腔膜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2、确定头尾方向3、就是胚体得组织中心The definitive endoderm（内胚层）and intraembryonic mesoderm（胚内 中胚层）form through the primitive streak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12the ectoderm外胚层the mesoderm 中胚层the epiblast上胚层 definitive endoderm内胚层 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 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）.4i mr ail r+-t 亦山Intermediate mesodermLateral pl ate mesodermNotochordal processParaxial mesodermmesodermSpl anchnopl euric mesoderm17 days8 days、Paraxial mesodermIntermediate mesodermLateral pl ate mesodermFigure 3-8.Sections through a 1 7-day embryo showing the differentiation of the mesoderm on either side of the midl ine.A,Earl y on day 1 7Z the mesoderm has begun to differentiate into paraxial,intermediate,and l ateral pl ate mesoderm.B,Sagittal cutaway showing the rod I ike condensations of paraxial and intermediate mesoderm.The dotted l ine marks the pl ane of the two transverse sections.C,Later on day 1 7Z the l ateral pl ate begins to vacuol ate to form the rudiment of the intraembryonic coel om.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：圆柱体四、三胚层得分化 1、外胚层得分化(1)神经管形成:neural neural neural neuralplate神经板 groove神经沟 fold 神经褶 tube 神经管脑、脊髓前神经孔未闭 无脑儿后神经孔未闭 脊髓裂脊柱裂Meningohydroencephalocele（MR 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 tubeHeadless mice The development and maintenance of the“head organizing center55 requires the expression of the homeobox gene Lim-1 Knock out of Lim-1 results in headless miceFigure 4-12.Neural crest cel l s arising at the l ateral edges of the neural pl ate detach during neurul ation and migrate throughout the embryo to form many different tissues.(2)神经喳分化围神经系统肾上腺髓质(3)表面外胚层:皮肤表皮及其附属器 小结：外胚层 分化神经系统、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、mesoderm differentiate(中胚层得 分化)：(1)paraxial mesoderm(轴旁中胚层)一 (somites)体节,第5周全部形成,共4244对,分化为真皮,大部分中轴骨与骨骼肌。(2)intermediate mesoderm(间介中胚 层)位于体节外侧，泌尿生殖系统发生得原基。(3)lateral plate mesoderm(侧中胚 层)分两层 A:Parietal mesoderm（体壁中胚层）：分 化为体壁得肌肉、结缔组织、浆膜壁层。B:Ventral mes为内脏平滑肌、乡胚内体腔:形成彳 3、Endoderm differentiate（内胚层得 分化）：随胚体得卷曲，内胚层形成原始消化管，内胚层：就是消化系统、呼吸系统与中耳、甲状腺、甲状旁腺、扁桃体、胸腺,膀胱与尿道等上皮得原基。四周人胚口咽膜 咽囊/五周人胚A.体节前胚B.7体节胚C.14体节胚D.4周末胚左列为整体外观，右列为相应的矢状断面观三周三胚层,体节神经兆。四周圆筒状,头大尾尖小,U FV八、1、=但神经板