|
怀孕
|
|
受精
|
|
|
|
受精：只有一个精子穿透卵子的外层。然后，精子的头和卵子的核融合，形成一个新细胞：受精卵。
Fertilization: Only one sperm cell penetrates the outer layer of the egg cell. The head of the sperm cell and the nucleus of the egg cell then unite and form a new cell: the zygote.
|
|
当卵子从卵巢释放出来时，它几乎立刻进入所毗邻的输卵管开口端。当她在输卵管内向子宫移动的时候，继续成熟，为与精子结合做好准备。数小时内，虽然卵子仍然位于输卵管的前1/3段，她却达到了成熟。如果受精将要发生的话，这恰恰是精子应该抵达的时候。精子与卵子能够结合的全部时间小于24小时。如果没有结合，卵子会死去和分解。可是，卵子迁移至输卵管时，可以很好地与性交数天后就已经到达输卵管并且留守的精子相结合。（已经发现，精子会在性交后于输卵管内存活达5天。）
|
|
Conception
|
|
Fertilization
|
|
When an egg is released
from one of the ovaries, it almost
immediately enters the open end of the
adjacent Fallopian tube. As it travels
down this tube toward the uterus, it
matures to become ready for the union
with a sperm cell. Within a few hours,
the egg reaches maturity while it is
still in the upper third of the
Fallopian tube. This is the time when
the sperm should arrive if a fertilization
is to occur. The
entire period in which egg and sperm can
unite is less than 24 hours.
If no such union takes place, the egg
dies and disintegrates. However, moving
into the Fallopian tube, the egg may
very well encounter live sperm cells
which have arrived and stayed there
following coitus several days before.
(Sperm cells have been found alive
inside Fallopian tubes up to five days
after coitus.)
|
