排卵与月经周期丨医学英语视听学习

Ovulation & the menstrual cycle

排卵与月经周期 

To understand the various ways that medical science can assist reproduction, it is important to understand how the reproductive system functions in both sexes, because the cause of infertility often lies equally with both men and women. 

学习各种医学助孕方法前，了解两性生殖系统的功能非常重要，因为男、女性发生不孕不育的病因通常一样。

The main players in the female reproductive cycle are the pituitary gland, the ovaries, and the uterus. Their activities are closely coordinated. Each month one or other ovary releases a single egg, an event known as ovulation. 

女性生殖周期的主要参与者是脑垂体、卵巢和子宫。它们密切配合。一侧或另一侧卵巢每个月释放一个卵子，这一事件称为【排卵】。

It is brought about by a series of complex interactions between the pituitary gland, the ovaries, and the uterus. The pituitary gland is itself under the control of this small area of the brain, known as the hypothalamus. 

它是由垂体、卵巢和子宫之间一系列复杂的相互作用引起的。垂体受大脑内称为下丘脑的小区域控制。

A new menstrual cycle begins when the nerve cells of this center secrete a hormone called gonadotrophins-releasing hormone, GnRH, into the network of blood vessels which surrounds the pituitary gland. 

当下丘脑的神经细胞将一种称为【促性腺激素释放激素（GnRH）】的激素，分泌入垂体周围的血管网时，新的月经周期开始。

Stimulated by pulses of gonadotrophins-releasing hormone, cells in the pituitary glands secrete another hormone, follicle-stimulating hormone or FSH. 

在GnRH脉冲的刺激下，垂体细胞分泌另一种激素，即促卵泡生成激素（FSH）。

FSH travels in the bloodstream, reaching the ovaries, there it stimulates the formation and growth of an ovarian follicle in one or other ovary. The follicle consists of an egg, a number of surrounding cells which secrete estrogen hormones, and fluid. 

FSH随血液运行，到达卵巢，刺激一侧或另一侧卵巢中卵泡形成和生长。卵泡由一个卵子，许多分泌雌激素的周围细胞，以及液体组成。

FSH helps the egg to mature and prepares it for release. As the follicle matures, the hypothalamus increases secretion of GnRH, this in turn stimulates the pituitary to secrete a second hormone which acts on the ovary. This is luteinizing hormone or LH.

FSH有助于卵子成熟，为释放做准备。随着卵泡成熟，下丘脑增加GnRH的分泌，这反过来刺激垂体分泌作用于卵巢的第二种激素，即黄体生成激素（LH）。 

Toward the middle of the cycle, there is a sudden peak in the blood level of LH. This acts as the trigger for ovulation.

血液中的LH水平在月经中期忽然达到峰值。这是排卵的触发因素。

Within minutes of its release, the egg is guided by suction through the fringed opening of the outer end of the fallopian tube, starting it on a journey which will take five or six days as it passes down the tube and finally reaches the cavity of the uterus. 

在释放后的几分钟内，卵子在吸引力作用下，通过输卵管外端的边缘开口；然后开始通过输卵管，最终到达子宫腔内，这一过程需要 5 或 6 天。

Meanwhile, after the follicle ruptures, it is converted into this yellowish body known as the corpus luteum. Cells at the corpus luteum secrete the hormone progesterone, which brings about important changes in the lining of the uterus, preparing it for possible pregnancy. 

与此同时，卵泡破裂后，转化为黄体，黄体细胞分泌黄体酮激素，使子宫内膜发生一些重要改变，为怀孕做准备。

In fact, the lining of the uterus known as the endometrium undergoes changes in response to hormone levels during the cycle. 

事实上，子宫内膜在月经周期会随着激素水平的变化而变化。

In the first half of the cycle, known as the follicular phase, the developing follicle secretes increasing amounts of estrogen hormone, which encourages regeneration of the endometrium. 

在前半周期--卵泡期，发育中的卵泡分泌更多雌激素，促进子宫内膜再生。

After ovulation, there are important changes in the endometrium aimed at making it suitable to receive a fertilized egg. These changes are brought about by a secretion of progesterone from the corpus luteum. 

排卵后，子宫内膜发生重要改变，为孕育受精卵做准备，而这些变化由黄体分泌黄体酮引起。

The secretion of progesterone is maintained for several days, but if the egg is not fertilized in that time, the corpus luteum withers and falling levels of progesterone and estrogen trigger the shedding of the uterine lining as the menstrual flow. The cycle then starts again.

黄体酮分泌将维持数天，但是如果卵子在此期间未受精，黄体会萎缩；黄体酮和雌激素水平下降会触发子宫内膜脱落。然后，月经周期重新开始。

But if the egg is fertilized, no menstruation occurs. As the corpus luteum continues to function, secreting progesterone during the first three months of the pregnancy, thereafter numerous changes occur to support the developing embryo. 

但是如果卵子受精，则不会有月经。黄体继续发挥作用，在妊娠的前3个月分泌黄体酮，而此后发生的各种变化将支持胚胎发育。