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..
Deep inside the woman, in her ovaries, one egg develops each month. From the man's testes, through his penis, millions of sperm enter the woman's vagina. Here, they begin their travel toward the egg. Only one sperm can enter an egg. When one does, fertilization occurs. Genetic material from the male and from the female combine, to create the first cell of an offspring. The fertilized egg migrates to the uterus where it develops into a fully formed fetus over a period of about 40 weeks. Then, a baby is born.