1 Transmission: neurons transmit these signals to pain-processing structures of the spinal cord and brain. 2  Modulation: the signals can be amplified or dampened at various points in the pathway to facilitate or inhibit transmission, thereby enhancing or reducing the sensation of pain.
The sperm usually fertilizes the egg in the Fallopian tubes. Then, the fertilized egg moves down to the uterus where it implants, causing pregnancy. The segment of the Fallopian Tube where fertilization commonly occurs is the ampulla..
In order for implantation to take place, ovulation and fertilization must occur first. Implantation happens early in the pregnancy stage after the fertilized egg (zygote) travels down the fallopian tube to the uterus and adheres to the epithelium, or uterine lining. It takes about eight to 10 days for the fertilized egg to travel to the uterus.