The vagina is the canal of muscle that begins behind the external female genitalia and extends to the cervix. This is also the tube through which babies are born in vaginal childbirth. The vagina is made of muscle and has a ridged surface. During sexual intercourse, the vagina produces moisture in preparation for penetration.
More About Vagina
Contrary to popular belief, the female genitalia includes several parts; the vagina is just one of the internal components of the female genitals. The vagina is elastic and typically six or seven inches in length. It ends at the cervix, which is at the bottom of the uterus. During vaginal childbirth, the cervix opens and the baby travels from the uterus, through the cervix, to the vagina and into the world.
During sex and stimulation, the glands located in the vagina produce lubrication to ease penetration. The first four inches or so of the vagina are especially sensitive to sexual stimulation. When a woman reaches orgasm, the muscles in the vagina contract.