外教讲解地道美语 第246期:生命的奇迹

A:   Continuing with our class, today we are going to study briefly the miracle of life. Many of you may think you already know how babies come to be, but I am sure that some of the things that we will be talking about today may surprise you. Billy ，can you turn on the projector please?  Thanks.  Ok, does anyone know what this is?

B:   Looks like a goat head to me!

A:   Nice try, but this is a woman’s womb which contains her uterus and ovaries.  The ovaries are packed with eggs and each month during the middle of the menstrual cycle, the ripest one will be  sucked up by one of the fallopian tubes.  This is called ovulation and the exact time of ovulation  depends on the length of your cycle. In an average 28 day cycle, ovulation will most likely happen between the 12th and 15th days, counting day 1  as the first day of your last period.

B:   That’s amazing! So each month, the woman produces these eggs and then waits for them to be  fertilized?

A:   Actually, every woman is already born with over four hundred thousand eggs! Some will start dying off immediately and others released during her fertile period.

B:   What about the guys? I know they produce sperm and stuff.

A:   That’s right!  The man’s body has a tiny factory that produces sperm twenty four hours a day! Each ejaculation will release about a hundred million sperm so the factory is always pretty busy.  The sole purpose of a sperm’s life is to fertilize the woman’s egg.

B:   So, then we basically need to put one-and-one together so we can have babies right?

A:   Yes, the man will have an orgasm during intercourse and ejaculate sperm and semen. Now this  is where the race begins and all those millions of sperm will race and swim from the cervix, through the uterus to the fallopian tubes. This could take anywhere from forty five minutes to twelve hours! Not all of them make it, since some go the wrong way and get lost or simply die. Many will actually  reach the egg but only one will penetrate it and fertilize it.  Once this happens, the egg instantly changes and creates a protective shield once the sperm is safely inside.

B:   And then? That’s it?

A:   Well,  the egg will be fertilized within about  24 hours of its release.  The genetic material from the sperm combines with the genetic material in the egg to create a new cell that will rapidly start dividing. The woman is not actually pregnant until that bundle of new cells, known as the embryo, travels the rest of the way down the fallopian tube and attaches itself to the wall of her uterus.  Any other questions? Then let’s move on.