胚胎






发育到第五个星期（或怀孕后第七个星期）的人类胚胎


胚胎（法语：Embryo）是专指有性生殖而言，是指精子和卵子合成为合子之后，经过多次细胞分裂和细胞分化后形成的有发育成生物成体的能力的雏体。它指的是发育生物学最早的阶段。


有性繁殖的生物体裡，一旦精子使卵子受孕，卵子就变成受精卵，并同时拥有精子和卵子的DNA。植物、动物、部分原生物中，受精卵会自发细胞分裂，并形成一个多细胞的生物体。胚胎指的就是这个发展形成过程的最初阶段，从受精卵开始第一次分裂，到下一阶段发展开始前。



參見


  • 動物胚胎發生


外部链接




  • 人类发展图表英


  • 胚胎比较画廊英


  • 人类胚胎發展英














前一状态
人类生命状态
下一状态

受精卵
胚胎
胎儿





维基共享资源中相关的多媒体资源：胚胎



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