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怀孕
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卵裂
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卵裂：
通过细胞分裂，受精卵发育成桑葚胚，然后发育成囊胚。
Segmentation:
The zygote, by cell division, grows into a morula an then into a
blastocyst.
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受精以后数小时内，也就是精子的细胞核与卵子的细胞核融合以后，所形成的这个受精卵开始内部的分裂过程。首先，它分裂成2个细胞，然后是4个、8个、16个……等等，随着每分裂一次，细胞数量加一倍。这种细胞的分裂或受精卵的分裂称为卵裂。卵裂把受精卵转换成称为桑葚胚的细胞团，它在显微镜下看起来象桑葚果。桑葚胚慢慢地沿输卵管向下、朝子宫移动，到达那里约需3天。到这个时候，它已经发育成一个叫囊胚的中空细胞球了。
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Conception
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Segmentation
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Within a few hours after fertilization, i.e. after the nucleus of the sperm has united with the nucleus of the egg, the result of their union, the zygote, begins a process of internal division. First, it divides into two cells, then four, eight, sixteen, and so on, doubling the number with each new division.
This process of cell division or cleavage in the zygote is called segmentation. It transforms the zygote into a cluster of cells called
morula which, seen through a microscope, resembles a mulberry. The morula slowly moves down the Fallopian tubes toward the uterus, where it arrives after about three days. By this time, it has developed into a hollow ball of cells called
blastocyst.
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