nal fertilization, and depends on the integrated action of hormones, the nervous system, and the reproductive system. Gonads are sex organs that produce gametes. Male gonads are the testes, which produce sperm and male sex hormones. Female gonads are the ovaries, which produce eggs and female sex hormones. The Male Reproductive SystemTestes are suspended outside the abdominal cavity by the scrotum, a pouch of skin that keeps the testes close or far from the body at an optimal temperature for sperm development. Seminiferous tubules are inside each testis, and are where sperm are produced by meiosis. About 250 meters (850 feet) of tubules are packed into each testis. Spermatocytes inside the tubules divide by meiosis to produce spermatids that in turn develop into mature sperm.SpermatogenesisSperm production takes place in the testes. The testes are in the scrotum. The scrotum is a sac located outside of the males body. Since sperm can develop only in an environment with a temperature that is about 3C lower than normal body temperature, the exterior position of the scrotum provides an ideal location.Located within each testis, a fine network of highly coiled tubes are the production facilities for sperm. Sperm are produced through the meiosis of cells lining these tubes. Meiosis produces haploid cells. One cell divides by meiosis and produce four cells that mature into sperm. In human males, the production of mature sperm takes about 74 days. A sexually mature male can produce about 300 million sperm per day, each of his life. A sperm is highly adapted for reaching and penetrating the female egg. It can live for about 48 hours inside the female reproductive tract. A sperm is composed of a head, a midpiece, and a tail. The head contains the nuclear material and is covered by a cap containing enzymes that facilitate penetration of the egg. A number of mitochondria are found in the midpiece; they provide energy for locomotion. ...
