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..
Normally, an egg is fertilized in the fallopian tube and becomes implanted in the uterus. However, if the tube is narrowed or blocked, the fertilized egg may never reach the uterus. Sometimes the fertilized egg then implants in tissues outside of the uterus, resulting in an ectopic pregnancy.