男性生殖发育

What changes happen during puberty?
::青春期发生什么变化?

A lot changes during this time. A boy has to start shaving, his voice deepens, he gets taller, as well as a few other changes.
::在此期间发生了许多变化。一个男孩必须开始刮胡子,他的声音越深,他越高,还有其他一些变化。

Sexual Development in Males
::男性的性发育

The only obvious difference between boys and girls at birth is their reproductive organs . However, even the reproductive organs start out the same in both sexes.
::男孩和女孩在出生时的唯一明显差别是生殖器官,但是,即使生殖器官在两性中开始也是一样的。

Development Before Birth
::出生前发育

In the first several weeks after , males and females are essentially the same except for their . Females have two X chromosomes (XX), and males have an X and a Y chromosome (XY). Then, during the second month after fertilization, genes on the Y chromosome of males cause the secretion of testosterone . Testosterone stimulates the reproductive organs to develop into male organs. (Without testosterone, the reproductive organs always develop into female organs.) Although boys have at birth, the organs are immature and not yet able to produce or secrete testosterone.
::在生育后的头几个星期,男性和女性基本相同,但女性除外。女性有2个X染色体(XX),男性有1个X和1个Y染色体(XY)。然后,在授精后第二个月,雄性Y染色体上的基因导致睾酮分泌。睾酮刺激生殖器官发展成雄性器官。 (没有睾酮,生殖器官总是发展成雌性器官。 )尽管男孩在生育时是非成熟的,但器官尚不能产生或分泌睾酮。

Puberty and Its Changes
::结核病及其变化

The reproductive organs grow very slowly during childhood and do not mature until . Puberty is the period during which humans become sexually mature. In the U.S., boys generally begin puberty at about age 12 and complete it at about age 18.
::生殖器官在童年时期发育非常缓慢,直到......才成熟。 胚胎是人类性成熟的时期。 在美国,男孩一般在12岁左右开始青春期,18岁左右完成青春期。

What causes puberty to begin? The hypothalamus in the brain “tells” the pituitary gland to secrete that target the testes . The main pituitary hormone involved is luteinizing hormone (LH) . It stimulates the testes to secrete testosterone. Testosterone, in turn, promotes and growth. It brings about most of the physical changes of puberty, some of which are shown in Figure . In addition to the changes shown below, during puberty male facial hair begins to grow, the shoulders broaden, and the male voice deepens. 
::是什么原因导致青春期的开始?大脑“洞穴”中脑部的下丘脑,即垂垂垂的腺,可以对睾丸进行隐秘。主要的垂垂体激素是润滑荷尔蒙(LH)。它刺激睾酮的睾丸,进而促进和成长。它带来青春期的大部分物理变化,其中一些变化在图中显示。除了下文显示的变化外,在青春期男性面部毛发开始生长,肩部扩大,男性声音深化。

Adolescent Growth Spurt
::青少年增长净化

Another obvious change that occurs during puberty is rapid growth. This is called the adolescent growth spurt . In boys, it is controlled by testosterone. The rate of growth usually starts to increase relatively early in puberty. At its peak rate, growth in height is about 10 centimeters (almost 4 inches) per year in the average male. Growth generally remains rapid for several years. Growth and of occur toward the end of the growth spurt in height. Muscles may continue to develop and gain strength after growth in height is finished.
::青春期期间出现的另一个明显变化是快速增长。这被称为青少年成长加速。在男孩中,由睾丸酮控制。在青春期,增长率通常开始相对较早地增长。在高峰期,平均男性的高度增长率约为每年10厘米(近4英寸),平均男性的年增长率约为每年10厘米(近4英寸 ) 。几年来,增长普遍保持快速。增长和接近高度增长的末期。肌肉在高度增长完成后可能继续发展和增长。

Summary
::摘要

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• The male reproductive system forms before birth but does not become capable of reproduction until it matures during puberty.
  ::男性生殖系统在出生前形成,但在青春期发育成熟之前不能生育。
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• Puberty lasts from about ages 12 to 18 years and is controlled by hormones.
  ::12至18岁的婴儿患有肺结核,受荷尔蒙控制。

Review
::回顾

播放段落
1. What happens to a developing baby that lacks testosterone?
   ::一个没有睾丸激素的发育中的婴儿会怎么样?
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2. List three physical changes that occur in males during puberty.
   ::列出男性在青春期发生的三种身体变化。
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3. Explain how and why boys change so much during puberty.
   ::解释为什么男孩子在青春期变化如此之大。