About 250 million sperm enter the vagina but most of them die within 30 minutes by deadly acids.
Uterotubal Junction and Fallopian Tube
Oh no they got away.
The rest of the sperm must travel through the cervix and try to get to the uterus without getting lost and dying.
The sperm have to navigate through the uterus and fallopian tube. The muscular contractions of the uterus will help the sperm swim. There are white blood cells that will try to kill the sperm.
Uterotubal Junction is the doorway to the fallopian tube. They are safe from the white blood cells. The sperm are provided with nourishment from the fallopian tube, so they cant stay alive for days.
The remaining sperm have to find the egg. The eggs releases chemicals that make the sperm swim faster. The sperm that makes contact with the "outer coat" of the egg has a bag of enzymes on it's head that explodes, which allows it to penetrate the "outer coat"of the egg.
The sperm and egg that connected travels down the fallopian tubes towards the uterus, cells begin dividing. 5 days later, the embryo breaks out of protective shell and implants in the wall of the uterus and begins growing.