human reproductive system summary

Sperm, male reproductive cell, produced by most animals. With the exception of nematode worms, decapods (e.g., crayfish), diplopods (e.g., millipedes), and mites, sperm are flagellated; that is, they have a whiplike tail. In higher vertebrates, especially mammals, sperm are produced in the testes.

Androgen, any of a group of hormones that primarily influence the growth and development of the male reproductive system. The predominant and most active androgen is testosterone, which is produced by the male testes. The other androgens, which support the functions of testosterone, are produced

Estrogen, any of a group of hormones that primarily influence the female reproductive tract in its development, maturation, and function. There are three major hormones—estradiol, estrone, and estriol—among the estrogens, and estradiol is the predominant one. The major sources of estrogens are the

Testis, in animals, the organ that produces sperm, the male reproductive cell, and androgens, the male hormones. In humans the testes occur as a pair of oval-shaped organs. They are contained within the scrotal sac, which is located directly behind the penis and in front of the anus. In humans each