福建哪里有手工活:子宫日记（5）

   In the womb 5

      After growing for eight weeks, the embryo looks more like a tiny human and becomes known as a fetus which in Latin means offspring. She has reached an important milestone. Until now the embryo has been dependent on the nutrients she could extract from her yolk sac(卵黄囊), a floating balloon connected to the base of the umbilical cord(脐带). A human yolk sac is used briefly and then vanishes. It is believed that for the first few weeks, it generates nutrients and blood cells for the tiny embryo.

       生长八周之后，现在的胚胎看起来更加像一个小人儿了，这个时候的胚胎已经可以称为胎儿，拉丁语就是子孙的意思。胚胎生长到达了一个重要的里程碑。胚胎一直依靠卵黄囊里的营养物质生长，卵黄囊是一个连在脐带底部的小球。人类的卵黄囊用得时间很短，很快就会消失。科学家认为，在最初几周里它能为小小的胚胎提供养分和血细胞。

     By two months, the yolk sac becomes redundant and shrivels away. The crucial job of feeding and nurturing the fetus is completely taken over by the placenta(胎盘), which is embedded into the wall of the uterus at the end of the umbilical cord. It provides nutrients while filtering out waste. The placenta is the fetus’s life support system during her time in the womb. It’s a network of very fine blood vessels, reaching into the wall of the uterus. Like the roots of a tree sucking nutrients from the soil, it extracts everything the fetus needs from the mother’s bloodstream, food, oxygen, water, and it filters it before passing it into the fetus’s bloodstream.

       两个月的时候，卵黄囊就已经失去了作用，慢慢萎缩变小。为胚胎提供营养的重担现在全部落到了胎盘身上。胎盘位于脐带末端，深入子宫壁。胎盘提供营养物质并且过滤掉废弃物，它是胎儿在子宫中的支持系统。胎盘有着细小的毛细血管网，一直延伸到子宫壁。像树木的根从土壤中吸收养料一样，胎盘也从母亲的血液中吸收所有胎儿生长需要的营养物质，食物、氧气、水，并且在这些物质进入胎儿的血液前对它们进行筛选。

       Blood, enriched by the mother’s diet, travels through the umbilical cord into the fetal arteries. Everything the fetus doesn’t need or the waste products are siphoned(用虹吸管吸出) out by the placenta and passed back into the mother’s bloodstream.

       血液浓缩了母亲食物的精华，通过脐带进入胎儿的动脉。所有胎儿不需要的废物被胎盘吸收回去，并送回母亲的血液中。

       The placenta also filters out many harmful substances that may be in the mother’s bloodstream and could damage the fetus. But it can’t stop everything and the mother has to be careful with things like prescription drugs, alcohol and nicotine, which will pass directly to the fetus.

       胎盘能过滤掉很多母亲血液中对胎儿有害的物质，但是它不能阻止所有的有害物质。所以母亲在使用处方药、酒精和尼古丁时特别要当心，因为这些物质会直接进入胎儿体内。

       Some pregnant mothers have an instinctive reaction to avoid food or drink that could be harmful to the fetus. They may be revolted by the smell of alcohol or seafood, meat or mushrooms. The mother’s body is effectively controlling her intake of food, telling her what to avoid and instigating cravings to ensure her child gets what it needs.

       一些怀孕的母亲会有一些本能反应，拒绝吃可能对胎儿有害的食物和饮品，一闻到酒精或者海鲜、肉和蘑菇等就会感到恶心。怀孕的身体控制着母亲所吃食物的种类，告诉她要拒绝哪些食物、多吃哪些孩子需要的食物。

       The first trimester can be an uncomfortable time for the mother. Apart from its nurturing role, the placenta also controls pregnancy by producing hormones, and early on these hormones are what give some women morning sickness. One of these, progesterone(黄体酮), is secreted(分泌) throughout the term and prevents the mother from releasing more eggs. Others stop the mother’s immune system from rejecting the unfamiliar growth inside her.

       怀孕的头三个月对母亲来说是非常不舒服的一段时期。除了提供养分，胎盘也产生荷尔蒙来控制怀孕的全过程，但是这些荷尔蒙会让一些妇女有晨呕的症状。其中一种叫作黄体酮，它在整个怀孕期间都会一直分泌，可以阻止母亲产生新的卵子。其他荷尔蒙则阻止了母亲的免疫系统对体内陌生生命的出现而产生的免疫反应。

       Another week passes and the nervous system is developing fast, spreading connections throughout the body. Over the course of nine months, the nervous system generates an average of two and a half million neurons every minute. The fetus has been still so far, but now at about nine weeks, her whole body starts to twitch. Movement plays a crucial role in stimulating the growth of muscles and strengthening of joints.

       又过了一周，神经系统迅速发展，神经网络慢慢布满胎儿的全身。在九个月的胎儿发育过程中，神经系统平均每分钟大约要产生250万个神经元细胞。胎儿到目前为止还是安静的，但是大约九周后，她的身体会有小的搐动。运动对加速肌肉的生长和关节的合拢起着关键的作用。

        At this stage, the nerves may only extend from the muscles of the leg, for example, back to the spinal cord. The connection to the brain is still growing. So the brain isn’t controlling the fetus’s movements yet. They are still involuntary reflex spasms(痉挛). The heart isn’t controlled by the brain yet, either. It marches to its own beat and it’s been gaining speed since its first twitch to life in the third week.

       在这个阶段，神经可能只长到腿部的肌肉等部位，比如已经发展到了脊柱，大脑的神经系统还在生长。所以大脑还不能控制胎儿的运动，胎儿的运动只是一些无意识的痉挛。心脏也没有被大脑控制，它一直自己跳动着，而且从第三周有了生命后跳动的速度就变得越来越快。

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