What is the structure of testis? Information on testis and its functions for reproduction.
Testis; the male gonad, or reproductive organ, which produces both sperm cells and male sex hormones (androgens). Testes are found in all animals that reproduce sexually. Some lower animals, such as earthworms, have both male and female gonads.
In humans, the testes descend from the abdominal cavity into the scrotum before birth. This prenatal descent also occurs in monkeys, goats, pigs, sheep, horses, and bulls. In other mammals, such as rats, the testes descend right after birth, and in elephants, stags, and some rodents they descend at the mating season. In fish, amphibians, reptiles, and birds, the testes are normally located in the abdominal cavity.
The human testis is composed of seminiferous tuhules, whose development during adolescence is stimulated by a hormone from the anterior pituitary gland, and interstitial, or Leydig, cells, which when stimulated by another pituitary hormone produce androgens, the most important of which is probably testosterone. Spermatogenesis, the formation of sperm cells, occurs in the seminiferous tubules. The mature sperm are stored in the epididymis and are discharged along with other substances through the ureter during ejaculation.