组织学与胚胎学 胚胎学2.ppt

Germdiscformanddifferentiate胚层的形成和分化主讲人:苏衍萍1、Developmentofthebilaminargermdisc(二胚层的形成,2w):(1)二胚层胚盘(bilaminargermdisc)。上胚层(epiblast)下胚层(hypoblast)羊膜腔(avity),卵黄囊(yolksac)。羊膜腔上胚层下胚层卵黄囊体蒂(bodystalk)(2)avitydevelopswithintheepiblast上胚层下胚层(3)Theformationoftheyolksac(卵黄囊形成)初级卵黄囊胚外中胚层的网状组织Ondays10to11,anacellularextraembryonicreticulumformbetweenHeuser’(4)Thehypoblastgivesrisetotheextraembryonicendodermthatlinestheprimaryyolksac(5)avityisproducedinconjunctionwiththedevelopmentoftheextraembryonicmesoderm(6)Thedefinitiveyolksacisformedbyanewwaveofcellsthatmigratefromthehypoblastanddisplaceheuser’smembrane2、三胚层的形成(第3周)(1)Theprimitivestreakappearsatthebeginningofthethirdweek(原条的出现,3w)原条primitivestreak原结primitivenode 原凹primitivepit原沟primitivegroove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胚盘脊索突原结原条泄殖腔膜中胚层