Section outline

  • Comparison of an egg surrounded by sperm, highlighting their size and shape differences.

    How is egg different from ?
    ::鸡蛋和鸡蛋有什么不同?

    Egg and sperm are both gametes , or reproductive cells . Notice how different they are, however. The egg is much larger than the sperm. The egg also does not have a tail. And the female only releases one egg at time, while the male releases millions of sperm at a time.
    ::鸡蛋和精子都是调子, 或者是生殖细胞。 注意它们有多么不同。 但是, 蛋比精子大得多。 蛋也没有尾巴。 雌性只释放一个蛋, 而雄性一次释放数百万个精子。

    Eggs and Egg Production
    ::鸡蛋和鸡蛋生产

    When a baby girl is born, her ovaries contain all of the eggs they will ever produce. But these eggs are not fully developed. They develop only after she starts having menstrual periods at about age 12 or 13. Just one egg develops each month. A woman will release an egg once each month until she is in her 40s. A girl is born with over a million eggs. They die off and by about 40,000 remain.
    ::当一个女婴出生时,她的卵子中包含了她们生下来的所有卵子。但是这些卵子还没有完全发育,只有在她12岁或13岁开始月经期之后才能发育。每个月只开发一个蛋。每个月,妇女将释放一个蛋,直到她40多岁。一个女孩出生后产卵超过100万个,死亡约40 000个。

    Eggs
    ::蛋蛋

    Eggs are very big cells. In fact, they are the biggest cells in the human female body. (How many egg cells are in the human male body?) An egg is about 30 times as wide as a sperm cell! You can even see an egg cell without a . Like a sperm cell, the egg contains a with half the number of chromosomes as other body cells. Unlike a sperm cell, the egg contains a lot of cytoplasm , the contents of the cell, which is why it is so big. The egg also does not have a tail.
    ::蛋是非常大的细胞。 事实上,蛋是人体女性体内最大的细胞。 (有多少蛋细胞在人体男性身体里? ) 蛋的宽度大约是精子细胞的30倍。 甚至可以看到没有精子细胞的蛋细胞。 蛋像精子细胞一样含有一半的染色体。 与精子细胞不同, 蛋含有大量的细胞, 细胞的内含, 这就是为什么它是如此大。 蛋也没有尾巴 。

    Egg Production
    ::鸡蛋生产

    Egg production takes place in the ovaries. It takes several steps to make an egg:
    ::卵蛋生产在卵巢中进行。

    1. Before birth, special cells in the ovaries go through (cell division), producing identical cells.
      ::在出生前,卵巢中的特殊细胞通过(细胞分裂),产生相同的细胞。
    2. The daughter cells then start to divide by . But they only go through the first of the two cell divisions of meiosis at that time. They go through the second stage of after the female goes through puberty.
      ::女儿的细胞开始分裂。但当时它们只经过两个细胞细胞中第一个细胞的细胞分裂。在雌性进入青春期后,它们进入了第二阶段。
    3. In a mature female, an egg develops in an ovary about once a month. The drawing below shows how this happens ( Figure ).
      ::在成年女性体内,卵子每月在卵巢中生长一次。下面的图示说明了这种情况是如何发生的(图 )。

    As you can see from the figure, the egg rests in a nest of cells called a follicle . The follicle and egg grow larger and go through other changes. The follicle protects the egg as it matures in the ovary.
    ::从图中可以看出,蛋藏在一个细胞巢中,叫做卵蛋。卵蛋和蛋长大,并经过其他变化。卵蛋在卵巢中成熟时会保护卵。

    After a couple of weeks, the egg bursts out of the follicle and through the wall of the ovary. This is called ovulation , which usually occurs at the midpoint of a monthly cycle. In a 28 day cycle, ovulation would occur around day 14. The moving fingers of the nearby fallopian tube  then sweep the egg into the tube. At this time, if sperm are present the egg can be fertilized.
    ::几周后, 卵从卵蛋中流出, 穿过卵巢的墙壁。 这被称为排卵, 通常在月周期的中点发生。 在28天的周期中, 排卵会在第14天左右发生 。 附近输卵管的移动手指 将卵排入管中。 此时, 如果有精子, 卵可以受精 。

    Egg development, follicle maturation, ovulation, and fertilization process in ovaries.

    This diagram shows how an egg and its follicle develop in an ovary. After it develops, the egg leaves the ovary and enters the fallopian tube. (1) Undeveloped eggs, (2) Egg and follicle developing, (3) Egg and follicle developing, (4) Ovulation. After ovulation, what remains of the follicle is known as the corpus luteum, which degenerates (5, 6).
    ::本图显示卵及其卵卵在卵巢中是如何发育的,卵子在发育后离开卵巢,进入输卵管。 (1) 未开发的蛋,(2) 卵和卵子的发育,(3) 卵和卵卵子的发育,(4) 排卵。排卵后,卵子的残留物被称为卵质润滑剂,其降解(5,6)。

    occurs if a sperm enters the egg while it is passing through the fallopian tube. When this happens, the egg finally completes meiosis. This results in two daughter cells that are different in size. The smaller cell is called a polar body . It contains very little cytoplasm. It soon breaks down and disappears. The larger cell is the egg. It contains most of the cytoplasm. This will develop into a child.
    ::当精子通过输卵管进入卵时,就会发生精子进入卵子的情况。一旦发生这种情况,卵子最终会完成 meiosisation。这导致两个女儿细胞的大小不同。较小的细胞被称为极体。它包含非常小的细胞体。它很快会分解并消失。更大的细胞是卵。它包含大部分细胞体。它会发展成一个孩子。

    Summary
    ::摘要

    • Eggs are female gametes that form in the ovaries and are released into the fallopian tubes.
      ::卵蛋是雌性色调,在卵巢中形成,并释放到输卵管中。
    • The eggs are formed before a baby girl is born, but these eggs are not fully developed.
      ::这些蛋是在女婴出生之前形成的,但这些蛋尚未充分发育。

    Explore More
    ::探索更多

    Use the resources below to answer the questions that follow.
    ::利用以下资源回答以下问题。

    Explore More I
    ::探索更多

    • Follicle Development  
      ::水晶开发
    1. What happens during ovulation? What happens to an egg after ovulation?
      ::排卵时会发生什么?排卵后蛋会怎么样?
    2. At what point is a zygote formed? How many chromosomes does a human zygote normally have?
      ::何时形成zygote?人类zygote通常有多少染色体?
    3. Where does implantation occur?
      ::植入在哪里发生?

    Explore More II
    ::探索更多情况二

    • Formation of Gametes  
      ::Gametes 的形成
    1. Is the primary oocyte diploid or haploid?
      ::主要的卵细胞浸泡液还是杂乱无章的?
    2. What structure forms from the primary oocyte? Is this structure diploid or haploid?
      ::从主卵细胞中得出何种结构形式? 这个结构是稀疏的还是杂交的?

    Review
    ::回顾

    1. Describe what happens during ovulation. When does this occur?
      ::描述排卵期间发生的情况。这是什么时候发生的?
    2. After ovulation, where does the egg go?
      ::排卵后,鸡蛋会到哪里去?
    3. Briefly describe egg production.
      ::简要描述鸡蛋生产。
    4. What is a polar body?
      ::什么是极体?