11.66 精子
Section outline
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How many sperm does it take to fertilize an egg ?
::给鸡蛋施肥需要多少精子?It might only take one sperm to fertilize an egg, but that sperm is not alone. Hundreds of millions of sperm can be released during sexual intercourse.
::精子可能只需要一个精子来施肥卵,但精子并不孤单。 数以亿计的精子可以在性交中释放出来。Sperm and Sperm Production
::精精和精生产Sperm ( Figure ), the male reproductive cells , are tiny. In fact, they are the smallest cells in the . What do you think a sperm cell looks like? Some people think that it looks like a tadpole . Do you agree?
::男性生殖细胞Sperm (图) 很小。 事实上, 它们只是其中最小的细胞。 你认为精子细胞长什么样? 有些人认为它像。 你同意吗?This drawing of a sperm shows its main parts. What is the role of each part? How do you think the shape of the sperm might help it swim?
::这幅精子图显示了精子的主要部分。 每个部分的作用是什么? 你觉得精子的形状能帮助它游泳吗?Sperm
::精精度A sperm has three main parts:
::精子有三个主要部分:-
The head of the sperm contains the
. The
nucleus
holds the
of the cell. The head also contains
enzymes
that help the sperm break through the
of an egg.
::精子的头部包含 。 核心控制着细胞。 头部也包含酶, 帮助精子穿透卵子 。 -
The midpiece of the sperm is packed with
mitochondria
.
Mitochondria
are
in cells that produce
energy
. Sperm use the energy in the midpiece to move.
::精子的中间体装满了米托乔恩德里亚,米托贡德里亚是产生能量的细胞。斯珀姆利用中间体的能量移动。 -
The tail of the sperm moves like a propeller, around and around. This tail is a long
flagella
that pushes the sperm forward. A sperm can travel about 30 inches per hour. This may not sound very fast, but don’t forget how small a sperm is. For its size, a sperm moves about as fast as you do when you walk briskly.
::精子的尾巴像螺旋桨一样到处移动。 这个尾巴是把精子推向前进的长旗子。 精子每小时可以行走约30英寸。 这听起来可能不太快,但不要忘记精子的大小。 对于精子的大小,其移动速度要像你走路时那样快。
Sperm Production
::精子生产To make sperm, cells start in the testes and end in the epididymis . It takes up to two months to make sperm. The steps are explained below:
::为了制造精子,细胞从睾丸开始,到肾上腺素结束。精子需要两个月的时间才能产生精子。步骤说明如下:-
Special cells in the testes go through
(cell division) to make identical copies of themselves.
::睾丸中的特殊细胞通过(细胞分部)制成相同的本子。 -
The copies of the original cells divide by
, producing cells called
spermatids
. The spermatids have half the number of
chromosomes
as the original cell. The spermatids are immature and cannot move on their own.
::原始细胞的复制件除以 , 产生被称为精子细胞的细胞。 精子的染色体数量是原始细胞的一半。 精子是不成熟的, 无法自行移动 。 -
The spermatids are transported from the testes to the epididymis. Involuntary muscular contraction moves the spermatids along.
::精子从睾丸转移到肾上腺素,非自愿肌肉收缩会让精子随波逐流。 -
In the
epididymis
, spermatids slowly grow older and mature. They grow a tail. They also lose some of the
cytoplasm
from the head. It is here that the spermatids mature, becoming sperm cells.
::在突触中,精子慢慢变老成熟。 它们长长尾巴。 它们还从头部中失去了一些细胞。 正是在这里,精子成熟,成为精细胞。 -
When sperm are mature, they can “swim.” The mature sperm are stored in the epididymis until it is time for them to leave the body.
::当精子成熟时,它们可以“游泳 ” 。 成熟精子储存在肾上腺素中,直到它们离开尸体的时候。
Sperm leave the epididymis through the vas deferens . As they travel through the vas deferens, they pass by the prostate and other glands. The sperm mix with liquids from these glands, forming semen . The semen travels through the urethra and leaves the body through the penis . A teaspoon of semen may contain as many as 500 million sperm!
::精液与这些腺的液体混合,形成精液。精液穿过尿道,然后通过阴茎离开身体。精液中的精液可能含有多达5亿精子!Summary
::摘要-
Sperm are male gametes that form in the testes and mature in the epididymis.
::精子是雄性游戏游戏 形成在睾丸中 成熟在肾上腺素中 -
The head of the sperm contains the nucleus, the midpiece is packed with mitochondria, and the tail moves like a propeller.
::精子的头部含有核, 中间体装满了米托孔德里亚, 尾部像螺旋桨一样移动。
Review
::回顾-
How many cells make up a sperm?
::有多少细胞组成精子? -
List the three main parts of a sperm.
::列出精子的三个主要部分。 -
What mostly make up the midpiece of a sperm? Why is this section important?
::精子的中间部分是什么? -
What is the function of the tail of a sperm?
::精子尾巴的功能是什么? -
Explain why sperm production is not completed when spermatids have been produced.
::解释为何在生产精子时精子生产没有完成。
-
The head of the sperm contains the
. The
nucleus
holds the
of the cell. The head also contains
enzymes
that help the sperm break through the
of an egg.
