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..
Once fertilization occurs, the fertilized egg will travel the remaining way through the Fallopian tube to the uterus. Implantation is when the fertilized egg burrows into the uterine lining and begins to grow. Implantation usually occurs between eight and ten days after the egg is fertilized. So if you have a twenty-eight-day menstrual cycle and ovulate on the 14th day, implantation would occur somewhere between day twenty-two and twenty-four of your cycle. If your cycle is longer than that, implantation would occur between two and four days before you would expect your next menstrual period.