1、 业精于勤荒于嬉 行成于思毁于随 【医学生物PPT，欢迎收藏分享】豆丁网友 1中国医科大学中国医科大学基础医学院基础医学院组胚组胚英文教学组英文教学组Formation and differentiation of trilaminar germ disc1. formation of epiblast and hypoblast : By the 8th day, the inner cell mass differentiates into two layers of cells epiblast (columnar) hypoblast (cuboidal)bilaminar germ
2、discAmnionic cavityepiblasthypoblastBilaminargerm disc-epiblast: primary ectoderm amniotic cavity: amniotic fluid roof: amniogenic cells floor: epiblast- hypoblast: primary endoderm hypoblast Heusers membrane primary yolk sacAmnionic cavityepiblasthypoblastBilaminargerm discExtra-embryonic mesodermP
3、rimary yolk sacBody stalkExtra-embryoniccavityExtra-embryonic mesodermPrimary yolk sacsecondary yolk sac extra-embryonic mesoderm extra-embryonic cavity (chorionic cavity) -visceral layer -parietal layer/secondary yolk sac: yolk sac-body stalk (connecting stalk): formed by extra-embryonic mesoderm2.
4、 formation of mesoderm: in the early of the 3rd week-primitive streak: cells of epiblast proliferate to form a longitudinal arranged cell cord * determination of head and tail of germ disc2. formation of mesoderm: in the early of the 3rd week-primitive streak-primitive node (primitive knot)2. format
5、ion of mesoderm: in the early of the 3rd week-primitive streak:-primitive node (primitive knot)-primitive pit (blastopore)-mesoderm: intra-embryonic mesoderm-endoderm: hypoblast cells are replaced by epiblast cells-ectoderm: epiblast changed the name into ectoderm by the end of the 3rd week trilamin
6、ar germ disc: endoderm + mesoderm + ectoderm -head processnotochordal tube notochord-buccopharyngeal membrane-cloacal membranenotochord3.differentiation of trilaminar germ disc 4th 8th weeks-differentiation: same cells which are primordial and inmuture differentiate into different cells which have s
7、pecific structure and function-induction: some tissues effect the differentiation, and determine the differentiating orientation of another tissue(1) differentiation of ectoderm: from 18th 19th days-neural plate: neuro-epithelium (neural ectoderm): pseudostratified columnar epi.neural plateNotochord
8、(1) differentiation of ectoderm: from 18th 19th days-neural plate-neural groove-neural foldNeural grooveNotochordNeural tubeAnterior and posterior neuropores-neural tube: CNS /anterior neuropore: closed by 25th days /posterior neuropore: closed by 27th daysanencephalySpina bifida-neural tube: CNS-ne
9、ural crest: two lines of cell cordsganglions(2)differentiation of mesoderm: 17th dayNeural grooveIntermediatemesodermLateral mesoderm paraxialMesoderm endoderm-paraxial mesoderm somite: 20th days, 3 pairs/per day, 42-44 pairs by the end of 5th weeks -sclerotome: bone, cartilage -dermatome: dermis an
10、d hypodermis -myotome: skeletal muscleIntermediatemesodermNeural canalSomite endodermIntraembryonic cavity-intermediate mesoderm: kidney and reproductive system-lateral mesoderm:Intra-embryonic coelom: body cavityparietal or somatic mesoderm: muscle, CT, parietal layer of pleura, peritoneum and peri
11、cardiumvisceral or splanchnic mesoderm: muscle, CT of digestive tract, visceral layer of pleura, peritoneum and pericardiumParietal mesodermvisceralmesodermIntra-embryoniccavity3. differentiation of endoderm: primitive gut: digestive, respiratory and urinary system foregutmidguthindgutCloacal membraneoropharyngeal membrane
