We're off to the sun, where we're going to fertilize it! We have to pass through the solar system first, though!
By Sydney Fitzpatrick and Lyvia Migliaccio
We've reached the vagina, now we have to make our way through the cervix!
Oh no! I'm lost in a passageway and I'm dying!
During intercourse, millions of sperm exit the penis through ejaculate and enter the vagina.
This is the vagina. Approximately 250 million sperm begin their journey here, but only one will finish. 90% of them die within 30 minutes of entering the vagina.
We're relaxing until the egg is released!
In the cervix, about 60,000 sperm must navigate through to the uterus. They swim single file through small channels in the cervical canal. Many die after getting stuck or lost in one of the thousands of passageways.
The sperm have now reached the uterus with approximately 3,000 of them left. the sperm have to find their way to the uterotubal junction and pass through the fallopian tube. The hardest part of passing through the uterus is fighting off the white blood cells also known has Leukocytes.
I know, and once we get there, we have time to relax and decompress while waiting for the egg
Wow, these white blood cells are crazy! We need to find the fallopian tube!
About 10-30 sperm remain. They are now safe from attacks by white blood cells, or Leukocytes. Sperm are provided with nourishment, and may stay alive for hours, or even days! During fertilization the remaining sperm race to find the egg in the fallopian tube. A single sperm will reach the egg, or ova, and once inside, will deliver 23 chromosomes to pair with the 23 chromosomes from the ova.
Look, there's the egg! I'm going to get there first!
The fertilized egg, or zygote, travels back down the fallopian tube and into the uterus, where the cells begin to divide. On the fourth day, the bundle of cells is named a blastocyst. 5 days later, the embryo breaks out of the outer shell and implants to the wall of the uterus, where it will grow into a baby.