uterus

The human reproductive organs. In the female, gametes called ova are released regularly in the ovaries after puberty. The Fallopian tubes carry the ova to the uterus or womb, in which the fetus will develop. In the male, sperm is produced inside the testes after puberty; about 10 million sperm cells are produced each day, enough to populate the world in six months. The sperm duct or vas deferens, a continuation of the epididymis, carries sperm to the urethra during ejaculation.

Hollow muscular organ of female mammals, located between the bladder and rectum, and connected to the Fallopian tubes above and the vagina below. The embryo develops within the uterus, and in placental mammals is attached to it after implantation via the placenta and umbilical cord. The lining of the uterus changes during the menstrual cycle to prepare it for pregnancy. In humans and other higher primates, it is a single structure, but in other mammals it is paired.

In fertilization a sperm fuses with an ovum and produces a zygote. The zygote sinks into the lining of the uterus. It then grows a placenta which brings the fetus's blood close to the mother's blood so that the fetus can obtain oxygen and nutrients. The outer wall of the uterus is composed of smooth muscle, capable of powerful contractions (induced by hormones) during childbirth.