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..
Among many animals, such as mammals, fertilization occurs inside the body of the female. Among fish, eggs are fertilized in the water. Among plants, fertilization of eggs occurs within the reproductive structures of the parent plant, such as the ovules of gymnosperms and angiosperms. See Note at pollination. The process of making soil more productive of plant growth, as by the addition of organic material or fertilizer.