The tiny oocyte moves along the fallopian tube.

微小的卵母细胞沿输卵管运动。

But right around birth, the oocytes stop developing — they get stuck in the first stage of meiosis.

但是在出生的时候，卵母细胞停止发育——它们卡在裂的第一阶段。

After ovulation, the secondary oocyte makes a very quick journey through the peritoneal space and lands in the fallopian tube.

排卵之后，次级卵母细胞会快速地通过腹膜，最后落入输卵管。

The truth is, most sperm never reach an oocyte.

事实是，大多精永远无法到达卵母细胞。

The ovaries contain follicles, which contain oocytes, which are immature eggs and surrounding cells.

卵巢中含有卵泡，卵泡中含卵母细胞，这是未熟的卵及其周围的细胞。

The secondary oocyte stops in metaphase of meiosis 2, and waits for fertilization as the menstrual cycle transitions into the luteal phase.

次级卵泡会在第二次裂中期停止裂，并且在卵泡期向黄体期转换的时候等待受精。

To do this, the primary oocytes have to complete meiosis 1, and in a person's lifetime only about 400 successfully do that.

要变就必须要经历第一次裂，而一个人的一生中大概只有400个初级卵母细胞可以做到。

Those enzymes are the key to getting through the oocyte's protective outer layers.

这些酶是穿过卵母细胞保护外层的关键。

If fertilization occurs - meaning if a sperm meets the secondary oocyte - then the corpus luteum continues making progesterone until the placenta forms.

如果这时候受精，精遇到次级卵母细胞，黄体会持续地泌黄体酮，直到胎盘形。

This tells the secondary oocyte to get ready to complete its second meiotic division.

这告诉次级卵母细胞准备完第二次裂。

The primary oocyte has 46 chromosomes, but eventually it has to turn into a gamete with only 23 chromosomes.

初级卵母细胞有46条染色体，但是最终会变只有23条染色体的。

The first part is the fimbriae which are the finger-like projections that surround the ovary and guide the secondary oocyte into the fallopian tube.

首先经过的是输卵管的伞部，呈指状突起，围着卵巢，并且可以引导次级卵母细胞进入输卵管。

Because once a path is cleared, a lucky sperm can wiggle against the now-exposed oocyte membrane until it locks onto another set of sperm-binding receptors.

因为一旦路径被清除，幸运的精可以在暴露的卵母细胞膜上摆动，直到它锁定到另一组精结合受体上。

Once it's past that, it runs into the zona pellucida, a layer of glycoprotein that covers the oocyte's plasma membrane.

一旦过了这个阶段，它就进入透明带，覆盖卵母细胞质膜的一层糖蛋白。

Meanwhile, the primordial follicle turns into a primary follicle, meaning that the follicular cells that surrounding the primary oocyte develop into granulosa cells.

与此同时，围初级卵母细胞的滤泡细胞化为颗粒细胞，使始基卵泡变为初级卵泡。

The first stage lasts from infancy to puberty, and during this stage the primary oocyte remains stuck in the prophase step of meiosis 1.

第一阶段从婴儿期到青春期，初级卵母细胞还停留在第一次裂的前期。

These two phases are separated by ovulation, which is when the follicle ruptures and releases an oocyte that is ready to be fertilized.

这两个阶段被排卵开，排卵即：卵母细胞被卵泡排出，准备好受精。

That's when the nearly 2 centimeter sized follicle ruptures and releases the tiny secondary oocyte into the fallopian tube.

此时将近2cm的卵泡破裂，向输卵管释放出次级卵泡。

Among the most important are the sertoli cells inside the tubes, which nourish developing sperm cells, sort of like how female follicle cells help oocytes.

其中最重要的是管内的支持细胞，它滋养发育中的精细胞，有点像女性卵泡细胞如何帮助卵母细胞。

In fact, sometimes only a dozen or so of the original millions make it through all those trials to actually reach an oocyte.

事实上，有时候几百万个卵母细胞中只有一打左右通过了所有这些试验最终得到了卵母细胞。