章节大纲

  • 常规

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  • 男性生殖系统的职能

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    Colorful Sperm
    ::色彩多彩精度

    This false-color image shows real human . The tiny gametes are obviously greatly magnified in the picture, because they are actually the smallest of all human . In fact, human sperm cells are small, even when compared with sperm cells of other . Mice sperm are about twice the length of human sperm! Human sperm may be small in size, but in a normal, healthy man, huge numbers of them are usually released during each ejaculation . There may be hundreds of millions of sperm cells in a single teaspoon of semen . Producing sperm is one of the major functions of the male reproductive system .
    ::假色图像显示的是真实的人类。在图片中,微小的调子显然大大放大,因为它们实际上是所有人类中最小的。事实上,人类精子细胞很小,即使与其他人的精子细胞相比,也很小。 老鼠精子大约是人类精子长度的两倍。 人类精子可能体积小,但是在正常、健康的人中,每次射精时通常会释放大量精子。 精子细胞在精子的单一茶壶里可能存在数亿个精子细胞。 生精是男性生殖系统的主要功能之一。

    Sperm Anatomy
    ::Sperm 解剖学

    A mature sperm cell has several structures that help it reach and penetrate an egg . These are labeled in the drawing of a sperm shown .
    ::成熟的精子细胞有几个结构帮助它接触和穿透一个蛋。这些结构在显示精子的图画中贴有标签。

    • The head is the part of the sperm that contains the — and not much else. The nucleus, in turn, contains tightly coiled that is the male parent’s contribution to the genetic makeup of a zygote (if one forms). Each sperm is a haploid cell, containing half the chromosomal complement of a normal, diploid body cell.
      ::头部是精子的一部分,包含的是精子 — — 而不是其他的。 核心则包含紧凑的螺旋,即男性父母对zygote(如果只有一种形式的话)基因构成的贡献。 每一个精子都是一个杂交细胞,包含正常的浸泡体细胞的染色体配料的一半。
    • The front of the head is an area called the acrosome . The acrosome contains that help the sperm penetrate an egg (if it reaches one).
      ::头部的前部是一个叫做杂交区。 杂交区含有有助于精子插入蛋( 如果精子达到一个)的精子。
    • The midpiece is the part of the sperm between the head and the flagellum . The midpiece is packed with that produce the energy needed to move the flagellum.
      ::中间部分是头部和旗之间的精子部分,中间部分是产生移动旗所需能量的精子。
    • The flagellum (also called the tail) can rotate like a propeller, allowing the sperm to “swim” through the female reproductive tract to reach an egg if one is present.
      :伤心也称尾巴)可以像螺旋桨一样旋转,让精子通过雌性生殖道“游动”,在有蛋时到达蛋。

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    Each normal mature sperm cell has the structures labeled in this image.
    ::每个正常的成熟精子细胞 都有这个图象标注的结构

    Spermatogenesis
    ::子形起源

    The process of producing sperm is known as spermatogenesis . Spermatogenesis normally starts when a boy reaches , and it usually continues uninterrupted until death, although a decrease in sperm production generally occurs at older ages. A young, healthy male may produce hundreds of millions of sperm a day! Only about half of these, however, are likely to become viable, mature sperm.
    ::精子的产生过程被称为精子的产生过程。 精子的产生通常从男孩到达时开始,并且通常持续到死亡为止,尽管精子的生产通常在年长时会减少。 年轻健康的男性每天可能生产数亿精子,但其中只有大约一半有可能成为可行、成熟的精子。

    Where Sperm Are Produced
    ::精子生产地点

    Spermatogenesis occurs in the seminiferous tubules in the testes . Spermatogenesis requires high concentrations of testosterone . Testosterone is secreted by Leydig cells, which are adjacent to the seminiferous tubules in the testes.
    ::睾丸中半圆形管的产生过程发生在睾丸中的半圆形管中; 睾丸子的产生需要高浓度的睾丸激素; 睾丸激素由与睾丸中半圆形管相邻的莱迪格细胞秘而不宣。

    Sperm production in the seminiferous tubules is very sensitive to temperature. This may be the most important reason the testes are located outside the body in the scrotum . The temperature inside the scrotum is generally about 2 degrees Celsius (almost 4 degrees Fahrenheit) cooler than core body temperature. This lower temperature is optimal for spermatogenesis. The scrotum regulates its internal temperature as needed by contractions of the smooth muscles lining the scrotum. When the temperature inside the scrotum becomes too low, the scrotal muscles contract. The contraction of the muscles pulls the scrotum higher against the body, where the temperature is warmer. The opposite occurs when the temperature inside the scrotum becomes too high.
    ::在半圆形管状管状体中,脉冲生产对温度非常敏感。这可能是睾丸位于细胞囊体外的最重要原因。 阴囊内的温度一般比核心体温低2摄氏度( 接近4华氏度) 。 这种较低的温度对精子产生最合适。 阴囊调节其内部温度, 以脉囊内滑动肌肉收缩所需的速度。 当囊内温度过低时, 细胞肌肉收缩会收缩。 肌肉的收缩会拉高细胞体, 温度比较暖的体体体。 相反, 当囊内的温度变得太高时, 就会发生相反的情况 。

    Events of Spermatogenesis
    ::Spermato起源事件

    The chart below summarizes the main cellular events that occur in the process of spermatogenesis. The process begins with a diploid cell called a spermatogonium (plural, spermatogonia), and involves several cell divisions. The entire process takes at least ten weeks to complete, including maturation in the epididymis .
    ::下面的图表概述了在精子产生过程中发生的主要细胞事件。 这一过程始于一个叫做精子原子的浸泡细胞( 花生、 精子) , 涉及多个细胞分裂。 整个过程至少需要十周时间才能完成, 包括性交时的成熟。

    1. A spermatogonium undergoes to produce two diploid cells called primary spermatocytes . One of the primary spermatocytes goes on to produce sperm. The other replenishes the reserve of spermatogonia.
      ::一种精子原子经过,可产生两种叫做初级精子细胞的低液细胞,一种主要精子细胞继续产生精子,另一种补充精子细胞的储备。
    2. The primary spermatocyte undergoes I to produce two haploid daughter cells called secondary spermatocytes .
      ::主要的精子细胞经历我 生产两个小产细胞 叫做二级精子细胞细胞
    3. The secondary spermatocytes rapidly undergo meiosis II to produce a total of four haploid daughter cells called spermatids .
      ::二级精子细胞迅速经历二号肾上腺素综合症,共产生4个叫精子细胞的产卵细胞。
    4. The spermatids begin to form a tail, and their DNA becomes highly condensed. Unnecessary cytoplasm and are removed from the cells, and they form a head, midpiece, and flagellum. The resulting cells are sperm (spermatozoa).
      ::精子开始形成尾巴,它们的DNA被高度凝结。 没有必要的细胞图像被从细胞中取出,形成头部、中间部和花旗。 由此形成的细胞是精子(spermatozoa ) 。

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    Spermatogenesis includes one mitotic division and two meiotic divisions.
    ::直径起源包括一个水上部和两个水上部。

    As shown in the figure , the events of spermatogenesis begin near the wall of the seminiferous tubule — where spermatogonia are located — and continue inward toward the lumen of the tubule. Sertoli cells extend from the wall of the seminiferous tubule inward toward the lumen, so they are in contact with developing sperm at all stages of spermatogenesis. Sertoli cells play several roles in spermatogenesis:
    ::如图所示,精子产生事件开始于精子产卵管的墙壁附近,并继续向管子的润滑剂向内渗透。 塞尔托利细胞从半子产卵管的墙壁向润滑剂向内延伸,因此它们在精子产生的各个阶段都与精子的开发接触。 在精子产生的各个阶段,塞托利细胞在精子产生方面起着几种作用:

    • They secrete endocrine that help regulate spermatogenesis.
      ::它们分泌内分泌 有助于调节精子的产生
    • They secrete substances that initiate meiosis.
      ::他们秘密物质 引发肾上腺素中毒。
    • They concentrate testosterone (from Leydig cells), which is needed at high levels to maintain spermatogenesis.
      ::它们浓缩睾酮(来自莱迪格细胞),这是保持精子产生所需的高水平的睾酮。
    • They phagocytize the extra cytoplasm that is shed from developing sperm cells.
      ::他们把开发精子细胞的 多余的细胞托盘 划入了细胞元体中。
    • They secrete testicular fluid that helps carry sperm into the epididymis.
      ::他们秘密的睾丸液 有助于将精子带入肾上腺素中
    • They maintain a blood-testis barrier, so immune system cells cannot reach and attack the sperm.
      ::它们保持血液测试屏障, 所以免疫系统细胞无法接触和攻击精子。

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    Cross-section of a testis and seminiferous tubules
    ::睾丸和半圆形管的横切体

    Maturation in the Epididymis
    ::埃皮迪迪米斯的成熟

    Although the sperm produced in the testes have tails, they are not yet motile (able to “swim”). The non-motile sperm are transported to the epididymis in testicular fluid that is secreted by Sertoli cells with the help of peristaltic contractions. In the epididymis, the sperm gain motility , so they are capable of swimming up the female genital tract and reaching an egg. The mature sperm are stored in the epididymis until ejaculation occurs.
    ::虽然睾丸中产出的精子有尾巴,但它们还不是运动的(可以用“滚动 ” ) 。 非运动的精子被运到睾丸液中的粘合体。 睾丸液由塞托利细胞在静脉收缩的帮助下秘密保存在睾丸液中。 在显性收缩中,精子变得多姿多彩,因此它们能够游到女性生殖道上,到达一个蛋。成熟精子在射精之前储存在粘合体中。

    Ejaculation
    ::射精

    Sperm are released from the body during ejaculation, which typically occurs during orgasm. Hundreds of millions of mature sperm — contained within a small amount of thick, whitish fluid called semen  —  are propelled from the penis during a normal ejaculation.
    ::精液在射精期间从身体中释放出来,这通常发生在高潮期间,数亿成熟精子在正常射精期间从阴茎中推出,这些精子中含有少量叫作精液的密密密液,这些精子在正常射精期间从阴茎中推出。

    How Ejaculation Occurs
    ::如何射精潜水

    Ejaculation occurs when peristalsis of the muscle layers of the vas deferens and other accessory structures propel sperm from the epididymes, where mature sperm are stored. The muscle contractions force the sperm through the vas deferens and the ejaculatory ducts, and then out of the penis through the urethra . D ue to the peristaltic action of the muscles, t he ejaculation occurs in a series of spurts.
    ::当血管延后和其他附属结构的肌肉层穿透时,就会发生射精。 肌肉收缩迫使精子通过血管延后和输卵管,然后通过尿道从阴茎中流出。由于肌肉的渗透作用,射精在一系列的脉冲中发生。

    The Role of Semen
    ::精人的作用

    As sperm travel through the ejaculatory ducts during ejaculation, they mix with secretions from the seminal vesicles , prostate gland , and bulbourethral glands to form semen (see photo ). The average amount of semen per ejaculate is about 3.7 mL, which is a little less than a teaspoonful. Most of this volume of semen consists of glandular secretions, with the hundreds of millions of sperm cells actually contributing relatively little to the total volume.
    ::随着精子在射精过程中穿透阴道,它们与精液囊、前列腺和球形腺的分泌物混合,形成精液(见照片)。每个精液中精液的平均含量约为3.7毫升,略低于茶匙。大部分精液由腺分泌组成,而成百上千万的精子细胞实际上对体积的贡献相对较少。

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    This petri dish shows normal human semen in a typical ejaculate.
    ::这个小菜碟展示出正常的人体精液 在典型的射精中

    The secretions in semen are important for the survival and motility of sperm. They provide a medium through which sperm can swim. They also include sperm-sustaining substances, such as high concentrations of the sugar fructose, which is the main source of energy for sperm. In addition, semen contains many alkaline substances that help neutralize the acidic environment in the female vagina . This protects the DNA in sperm from being denatured by acid, and prolongs the life of sperm in the female reproductive tract.
    ::精子的分泌对于精子的生存和运动很重要,它们提供了精子可以游泳的媒介,还包括精子的维持物质,例如高浓度的糖蓝糖,这是精子的主要能量来源;此外,精子含有许多碱性物质,有助于消除女性阴道中的酸性环境;这保护精子中的DNA不会因酸而变硬,延长女性生殖道的精子寿命。

    Erection
    ::平平,平平,平平,平平,平平平,平平,平平,平平,平平,平平,平平,平平,平平,平平,平平,平平,平平,平平,平平,平平,平平平,平平,平平,平平,平

    Besides providing a way for sperm to leave the body, the main role of the penis in is intromission, or depositing sperm in the vagina of the female reproductive tract. Intromission depends on the ability of the penis to become stiff and erect, a state referred to as an erection. The human penis, unlike that of most other mammals , contains no erectile . Instead, in order to reach its erect state, it relies entirely on engorgement with of its columns of spongy tissue . During sexual arousal, the arteries that supply blood to the penis dilate, allowing more blood to fill the spongy tissue. The now-engorged spongy tissue presses against and constricts the veins that carry blood away from the penis. As a result, more blood enters than leaves the penis, until a constant erectile size is achieved.
    ::除了提供精子离开身体的方法外,阴茎的主要作用是内向,或将精子放入雌性生殖道的阴道中。内向取决于阴茎是否能够硬起来和勃起,一种被称为勃起的状态。与大多数其他哺乳动物不同,人体阴茎没有勃起的状态。相反,为了达到其勃起状态,它完全依靠凝固其海绵组织柱。在性振奋期间,为阴茎提供血液的动脉膨胀,允许更多的血液填充海绵组织。现在的凝固的海绵组织对从阴茎中携带血液的血管进行压紧和压紧。结果,血液进入阴茎的血管比离开阴茎的血管要多,直到达到固定的竖立体大小。

    In addition to sperm, the penis also transports urine out of the body.  These two functions cannot occur simultaneously. During an erection, the sphincters that prevent urine from leaving the bladder are controlled by centers in the brain so they cannot relax and allow urine to enter the urethra.
    ::除了精子之外,阴茎还会将尿液运出身体,这两个功能不能同时发生。在勃起时,阻止尿液离开膀胱的指环由大脑中心控制,这样它们就不能放松,不能让尿液进入尿道。

    Testosterone Production
    ::生产睾酮

    The final major function of the male reproductive system is the production of the male sex hormone testosterone. In mature males, this occurs mainly in the testes. Testosterone production is under the control of luteinizing hormone (LH) from the pituitary gland . LH stimulates Leydig cells in the testes to secrete testosterone.
    ::男性生殖系统的最后一个主要功能是生产男性性激素睾酮,在成年男性中,主要发生在睾丸中,睾丸酮的生产受来自垂体腺的润滑荷尔蒙(LH)的控制,LH刺激睾丸中的Leydig细胞进入睾丸内,以隐匿睾丸酮。

    Testosterone is important for male sexual at puberty. It stimulates maturation of the male reproductive organs , as well as the development of secondary male sex characteristics (such as facial hair). Testosterone is also needed in mature males for normal spermatogenesis to be maintained in the testes. Follicle stimulating hormone (FSH) from the pituitary gland is also needed for spermatogenesis to occur, in part because it helps Sertoli cells in the testes concentrate testosterone to high enough levels to maintain sperm production. Testosterone is also needed for proper functioning of the prostate gland. In addition, testosterone plays a role in erection, allowing sperm to  be deposited within the female reproductive tract.
    ::睾丸酮对于青春期男性的性行为很重要,它刺激了男性生殖器官的成熟,以及男性第二性特征的发育(如面部毛发),成熟男性也需要睾丸酮才能保持正常的精子产生;此外,睾丸激素刺激性激素(FSH)也是产生精子所必需的,部分原因是它帮助睾丸中塞托利细胞的睾丸激素浓度达到足以维持精子生产的水平;睾丸酮也是前列腺正常功能所必需的;此外,睾丸酮在勃起中发挥作用,允许精子沉入雌性生殖器官中。

    Feature: My Human Body
    ::特质:我的人体

     

    If you’re a man and you use a laptop computer on your lap for long periods of time, you may be decreasing your fertility. The reason? A laptop computer generates considerable heat, and its proximity to the scrotum during typical use results in a significant rise in temperature inside the scrotum. Spermatogenesis is very sensitive to high temperatures, so it may be adversely affected by laptop computer use. If you want to avoid the potentially fertility-depressing effect of laptop computer use, you might want to consider using your laptop computer on a table or other surface rather than on your lap — at least when you log on for long computer sessions. Other activities that raise scrotal temperature and have the potential to reduce spermatogenesis including soaking in hot tubs, wearing tight clothing, and biking. Although the effects of short-term scrotal heating on fertility seem to be temporary, years of such heat exposure may cause irreversible effects on sperm production.
    ::如果你是一个男人,并且长期使用膝上型计算机,那么你可能会降低你的生育率。原因就是:膝上型计算机会产生相当高的热量,在典型使用期间,其接近阴囊导致阴囊的温度在阴囊内大幅上升。 光蛋的产生对高温非常敏感,因此可能会受到膝上型计算机使用的不利影响。 如果您想避免膝上型计算机使用可能造成的生育力抑制效应,那么你可能会考虑在一张桌子或其他表面而不是膝上使用你的膝上型计算机 — — 至少在你登录很长的电脑会话时是如此。 其他提高毛球温度并有可能减少精子生成的活动,包括在热浴缸中浸泡、穿紧身衣服和骑车。 尽管短期的手间取暖对生育能力的影响似乎是暂时的,但这种热暴露多年可能会对精子生产产生不可逆转的影响。

    Summary
    ::摘要

    • Parts of a mature sperm include the head, acrosome, midpiece, and flagellum. The process of producing sperm is called spermatogenesis. This normally starts during puberty, and continues uninterrupted until death.
      ::成熟精子的一部分包括头、 精质、 精质、 中子、 和。 精子的产生过程被称为精子产生过程。 这通常在青春期开始,并且持续到死亡为止。
    • Spermatogenesis occurs in the seminiferous tubules in the testes, and requires high concentrations of testosterone. Sertoli cells in the testes play many roles in spermatogenesis, including concentrating testosterone under the influence of follicle stimulating hormone from the pituitary gland.
      ::睾丸的发源地是睾丸中的微小管,需要高浓度的睾丸激素。 睾丸中的塞托利细胞在精子产生中起着许多作用,包括受肠泡刺激性胸腺激素影响而集中的睾丸激素。
    • Spermatogenesis begins with a diploid stem cell called a spermatogonium, which undergoes mitosis to produce a primary spermatocyte. The primary spermatocyte undergoes meiosis I to produce haploid secondary spermatocytes, and these cells in turn undergo meiosis II to produce spermatids. After the spermatids grow a tail and undergo other changes, they become sperm.
      ::子细胞起源于一种叫做精子原子的稀释干细胞,它会通过二次精子细胞生成。 主要的精子细胞会通过二次精子细胞生成,而这些细胞又会通过二次精子细胞生成。 在精子生长尾巴并发生其他变化后,它们会变成精子。
    • Before sperm are able to “swim,” they must mature in the epididymis. The mature sperm are then stored in the epididymis until ejaculation occurs.
      ::在精子能够“游泳”之前,它们必须在肾上腺素中成熟。 成熟精子随后储存在肾上腺素中,直到射精。
    • Ejaculation is the process in which semen is propelled by peristalsis in the vas deferens and ejaculatory ducts from the urethra in the penis. Semen is a whitish fluid that contains sperm and secretions from the seminal vesicles, prostate gland, and bulbourethral glands. These secretions are important for sperm survival and motility.
      ::精液是一种精液,含有精液、精液、前列腺和球形的分泌物。这些精液对于精子的生存和运动很重要。
    • Besides ejaculating sperm, another reproductive role of the penis is intromission, which is depositing sperm in the female vagina. This requires the penis to become stiff and erect, a state referred to as an erection. Erection usually occurs with sexual arousal as the columns of spongy tissue inside the penis become engorged with blood.
      ::除了精子射精外,阴茎的另一个生殖作用是内向,即将精子放入女性阴道。这就要求阴茎僵硬和勃起,被称为勃起。 阴茎中的海绵组织柱在血液中凝结时,通常会发生性刺激。
    • Leydig cells in the testes secrete testosterone under the control of luteinizing hormone (LH) from the pituitary gland. Testosterone is needed for male sexual development at puberty, and to maintain normal spermatogenesis after puberty. It also plays a role in prostate function and penis's ability  to become erect.
      ::睾丸蛋白质素(LH)控制下的睾丸激素(LH)控制下的睾丸激素(LH),男性在青春期的性发育需要睾丸激素,在青春期后保持正常的精子产生,在前列腺功能和阴茎勃起能力方面也起着作用。

    Review
    ::回顾

    1. List parts of a mature sperm.
    ::1. 列出成熟精子的组成部分。

    2. What is spermatogenesis? When does it occur?
    ::2. 精子起源是什么?何时发生的?

    3. Where does spermatogenesis take place? State one role of Sertoli cells in spermatogenesis.
    ::3. 在哪里产生精子?Sertoli细胞在精子产生中的作用之一。

    4. Summarize the steps of sperm production, naming the cells and processes involved.
    ::4. 概述精子生产的步骤,点出所涉及的细胞和过程。

    5. What must happen to sperm before they are able to “swim”?
    ::5. 精子在能够 " 游泳 " 之前必须发生什么情况?

    6. What is ejaculation?
    ::6. 什么是射精?

    7. Describe semen and its components.
    ::7. 描述精液及其成分。

    8. Define intromission. How is it related to erection?
    ::8. 内向定义:与勃起有何关系?

    9. Explain how erection occurs.
    ::9. 解释如何勃起。

    10. What cells secrete testosterone? What controls this process?
    ::10. 什么细胞秘密睾酮?什么控制这个过程?

    11. Identify functions of testosterone in males.
    ::11. 确定雄性睾酮的功能。

    12. Which of the following cells are haploid? Choose all that apply.
    ::12. 下列哪个单元格是杂交单元格? 选择所有适用单元格。

    a. spermatids
    ::a. 精子

    b. spermatogonia
    ::b. 精子蛋白

    c. primary spermatocytes
    ::c. 初级精子细胞

    d. secondary spermatocytes
    ::d. 二次精子细胞细胞

    e. mature sperm
    ::e. 成熟精子

     

    13. Describe one way in which Leydig and Sertoli cells work together to maintain spermatogenesis.
    ::13. 说明莱迪格和塞尔托利细胞为保持精子产生而共同工作的一种方式。

     

    14. True or False:  When it is cold outside the body, the scrotal muscles relax.
    ::14. 真实或假:身体外面寒冷时,阴毛肌肉放松。

     

    15. True or False:  During an erection, the arteries and veins of the penis dilate.
    ::15. 真实或假:在勃起期间,阴茎的动脉和静脉膨胀。

    Explore More
    ::探索更多

    There are many lifestyle factors that affect the quality of a man's sperm. Learn more here:
    ::影响男性精子质量的生活方式因素很多。

    Watch this video to learn more about spermatogenesis:
    ::观看这段影片以了解更多精子起源: