human reproductive system summary

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Below is the article summary. For the full article, see human reproductive system.

Organs of the human reproductive system. In a male, the scrotum, a pouch of skin, is divided into two sacs, each containing a testis and its associated epididymis. Tubules within the testes contain sperm cells at different stages of development. As sperm leaves the testes, it passes into the epididymis, a highly coiled tube that serves as a reservoir for sperm. The vas deferens, a duct leading out from the epididymis, joins with the duct of the seminal vesicles as it passes through the prostate gland to form a single tube (ejaculatory duct) that opens into the urethra, the tube that conveys both sperm and urine out through the penis. In a menstruating woman, a follicle containing an egg matures each month in either of two ovaries. Ovulation occurs as the mature follicle ruptures and releases an egg, which is drawn into the ovary's associated fallopian (uterine) tube, which contains a fringe of fingerlike projections (fimbriae). Fertilization usually occurs in the fallopian tube as the egg travels to the uterus. Successful implantation of a fertilized egg in the uterus results in development of an embryo. The vagina, a muscular tube that leads to the uterus, allows sperm to pass into the uterus and serves as a passageway for the fetus during childbirth.

human reproductive system, Organ system by which humans reproduce. In females, the ovaries sit near the openings of the fallopian tubes, which carry eggs from the ovaries to the uterus. The cervix extends from the lower end of the uterus into the vagina, whose opening, as well as that of the urethra (see urinary system), is covered by four folds of skin (the labia); the clitoris, a small erectile organ, is located where the labia join in front. The activity of the ovaries and uterus goes through a monthly cycle of changes (see menstruation) throughout the reproductive years except during pregnancy and nursing. In males, the testes lie in a sac of skin (the scrotum). A long duct (the vas deferens) leads from each testis and carries sperm to the ejaculatory ducts in the prostate gland; these join the urethra, which continues through the penis. In the urethra, sperm mixes with secretions from the seminal vesicles, prostate gland, and Cowper gland to form semen. In early embryos, the reproductive systems are undetermined. By birth the organs appropriate to each sex have typically developed but are not functioning. They continue to grow, and at puberty their activity increases and maturation occurs, enabling sexual reproduction.

sperm 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 Summary

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

pathways in the biosynthesis of steroid hormones

estrogen Summary

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

Human male testis, epididymis, and ductus deferens.

testis Summary

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