1. You’ve heard of the birds, and also the bees
Compared to how they reproduce, our way’s a breeze
So here’s a little introduction, some mighty good instruction
About human reproduction.
We’ll start with the female—in ovulation
The ovary releases an egg, awaitin’ fertilization
In the Fallopian tube, a sperm can pierce the egg’s coat
The two nuclei fuse, and you’ve got a zygote
The zygote divides many times, forms a hollow ball (the blastocyst)
Which implants itself in the uterine wall
‘Til it’s eight weeks old, it’s an embryo
Grows through the fetal stage, and then it’s got to go
Through the cervix, vagina, then out into the air
And if your mother’s lucky, you’re not too hard to bear!
Now let’s back up a minute, and bring in the male
That provided that sperm, with a flagellum like a tail
In the seminiferous tubules of the testes millions of sperm cells are formed
They mature in the epididymus, but they can’t get too warm (the scrotum keeps the testes
~2oC below body temperature)
In ejaculation the epididymus contracts,
Sperm move through the vas deferens and urethra, then out—that’s a fact
But the volume from the testes isn’t that great
Semen’s mostly from the seminal vesicles (~60%) and the prostate (with a small contribution
from the bulbourethral [also called Cowper’s] gland)
‘Course the urethra’s in the penis—used for semen injection
In intercourse it’s filled with blood, it’s called an erection
Releasing semen in the vagina is just the beginning
For sperm to reach the egg, sperm has got to get swimming!
Through the cervix and the uterus to the Fallopian tube
Where the egg is fertilized—that’s how Mom and Dad made you.
Song – Reproductive system