Developmental Biology 蛙类的囊胚腔的形成:第一次分裂后两个子细胞的动物 极端相接触,产生一个裂缝,它将扩大成为囊胚腔。 囊胚腔的作用:有利于原肠作用期细胞的移动、防止囊 胚腔上下细胞的过早交流。 Figure 10.3 Formation of the blastocoel in a frog egg. (A) First cleavage furrow, showing a small cleft, which later develops into the blasto- cocl. (B)8-cell embryo showing a small blastocoel (arrow) at the junction of the three cleavagefurrows From Kalt 1971; photographs courtesy of M. R. Kalt
Developmental Biology 蛙类的囊胚腔的形成：第一次分裂后两个子细胞的动物 极端相接触，产生一个裂缝，它将扩大成为囊胚腔。 囊胚腔的作用：有利于原肠作用期细胞的移动、防止囊 胚腔上下细胞的过早交流
Developmental Biology 螺旋型全卵裂:均采经线裂。第三次分裂前,卵裂球内 的纺锤体转动45度,然后向动物极方向出芽小卵裂球。其后 的大卵裂球以同样方式产生一大一小子分裂球,而小分裂球 只生成小卵裂球。 形成的囊胚无囊胚腔。 (A) View trom animal poke polar boy. itm Md- orth cew. re is langur thuan the oth divided into large and small spirally rented cells (Inn Craig and Morell oll Clavate is dextral. (A)8-cell stage, posh, curtesy of the author) (B) Sideview Spiral clevage of the molluse Taches color. The mitotic spindles, sketched in viewed (A)from the animal pole and the early stages, divide the cells (B)from one side. In(B). the cells unequally and at an angle to the vertical derived from the A blastomere are in and horizontal axe
Developmental Biology 螺旋型全卵裂：均采经线裂。第三次分裂前，卵裂球内 的纺锤体转动45度，然后向动物极方向出芽小卵裂球。其后 的大卵裂球以同样方式产生一大一小子分裂球，而小分裂球 只生成小卵裂球。 形成的囊胚无囊胚腔
Developmental Biology 旋转型全卵裂 哺乳动物的早期卵裂发生在输卵管中。 2-cell stage Zona pellucida Uterus First cleavage Figure 5.18 Development of a human embryo from Oviduct fertilization to implantation Compac- Morula/no tion in human embryos takes place at day 4, when it is at the 10-cell stage. The Blastocyst ③然 egg"hatches"from the zona upon reaching the uterus, and the zona prob ry ably prevents the cleaving cells from Early stage of Fertilization sticking to the oviduct rather than trav- implantation Ovulation eling to the uterus. (After Tuchman Duplessis et al., 1972.)
Developmental Biology 旋转型全卵裂 哺乳动物的早期卵裂发生在输卵管中
Developmental Biology 哺乳动物旋转型全卵裂:第1次为经线裂,其后的2个卵 裂球各采不同的卵裂方式 早期卵裂球的卵裂不同步,可产生奇数细胞的胚胎。 Cleavage Cleavage Cleavage Figure 5. 19 lane I Cleavage lane I Comparison of early cleavage in(A) plane IIA echinoderms(radial cleavage) and (B) mammals(rotational cleavage Nematodes also have a rotational form of cleavage, but they do not form the blasto- cyst structure characteristic of mammals Details of nematode cleavage will be given in Chapter 13. (After Gulyas, 1975) Clava plane lIB (A)ECHINODERM (B)MAMMAl (Sea urchin (Rabbit)
Developmental Biology 哺乳动物旋转型全卵裂：第1次为经线裂，其后的2个卵 裂球各采不同的卵裂方式。 早期卵裂球的卵裂不同步，可产生奇数细胞的胚胎
Developmental Biology 哺乳动物卵裂球的 compaction:发生第三次卵裂后不久 Figure 5. 20 The cleavage of a single mouse embryo cell stage.(E)Morula. (F) Blastocyst in vitro. (A)2-cell stage. (B)4-cell stage (From Mulnard, 1967, courtesy of ). G (C)Early 8-cell stage. (D)Compacted 8 Mullard)
Developmental Biology 哺乳动物卵裂球的compaction:发生第三次卵裂后不久