The endometrium evolved to make implantation difficult so that only the healthy embryos could survive.

子宫膜经演化， 使得着床难以进行因此，只有健康的胚胎能够生存。

If fertilization does happen, then the new embryo snuggles into the endometrium for gestation — but the uterus is only receptive to implantation for a short time, about a week after ovulation.

如果受精确实发生了，那么新胚胎会依偎在子宫膜中怀孕——但是子宫只接受着床很短的时间，大约在排卵后一周。

Because the egg has not been fertilized, the uterus lining called the endometrium is not needed, and hence it breaks down and is lost through the vaginal canal with some blood.

因为卵子没有受精，子宫膜就不被需要了，因此它会解，随着一些血液通管流。

During puberty, the monthly menstrual and ovarian cycles begin, which is when the endometrium, or inner lining of the uterus, goes through cyclic changes in response to the ovarian hormones.

在青春期，月经和卵巢周期开始出现，此时子宫膜（或子宫衬）对卵巢激素作出反应，发生周期性变化。

The endometrium evolved to make implantation difficult

子宫膜不断演化 使得着床变得困难。

If fertilization doesn't occur, the spiral arteries collapse, and the superficial layers of the endometrium die.

如果卵子没有受精，螺旋动脉将会收缩，子宫膜的表层也会因此凋亡。

Estrogen is produced by the ovaries and causes the uterus, lining the endometrium, to thicken again after menstruation so that it is ready to receive an embryo.

雌激素是由卵巢产生的，它使子宫膜在月经后再次变厚，以便为胚胎的形成做好准备。

The rising estrogen levels in the follicles stimulate the regeneration of the endometrium, building a cushy, well-vascularized habitat for another potential fertilized egg to call home.

卵泡中雌激素水平的上升刺激子宫膜的再生，为另一个潜在的受精卵建立一个舒适、血管发达的栖息地。

And if fertilization didn't happen, the corpus will stop producing progesterone, and the endometrium will start to shed its functional layer. And it starts all over again.

如果没有受精，体将停止产生黄体酮，子宫膜将开始脱落其功能层。一切又重新开始了。

And that's the first phase of the uterine, or menstrual cycle — the series of changes that the endometrium goes through every 28 days or so, in response to changing hormone levels, and in coordination with the ovarian cycle.

这是子宫的第一阶段，或者说月经周期——子宫膜每 28 天左右经历的一系列变化，这些变化是对激素水平变化的响应，并与卵巢周期相协调。

In the uterus, for example, they found one specific fibroblast subtype, S11, that only lived in the inner lining, the endometrium.

例如在子宫中，他们发现了一种特定的成纤维细胞亚型S11，这种细胞仅存在于膜（子宫膜）中。

The embryo engages in a complex, exquisitely timed hormonal dialogue that transforms the endometrium to allow implantation.

胚胎参与一场复杂而精确计时的激素对话，将子宫膜转变为适合着床的状态。

Previous studies have consistently shown associations between adiposity, excess weight, and increased risk of certain cancers, so endometrium, kidney, and gall bladder for women, breast in post-menopausal women, and colon in men.

以前的研究一致表明肥胖、超重和某些癌症风险增加之间存在关联，因此女性的子宫膜、肾脏和胆囊、绝经后女性的乳房和男性的结肠。

There, it requires another three or so days to implant firmly into the endometrium, the inner lining of the uterus.

在那里， 还需要大约三天的时间才能牢固地植入子宫膜，即子宫的膜层。

During the follicular phase of the menstrual cycle, the endometrium thickens in case fertilization occurs, during the luteal phase, spiral arteries emerge to bring more nutrients to support the thick endometrium.

在月经周期中的卵泡期，子宫膜会变厚，有助于受精；黄体期，螺旋动脉产生可以为增厚的子宫膜提供更多养。