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How the reproductive system works

The female reproductive system.

Your reproductive system: On the inside

Your reproductive system — all the parts of your body that help you reproduce, or have babies — is quite amazing. From the time you’re born, you likely have hundreds of thousands of eggs. And right inside you is a perfect place for those eggs to meet with sperm and grow a whole human being! Let’s take a look at what’s going on inside a young woman’s reproductive system.

The ovaries are two small organs. Before puberty, it’s like the ovaries are asleep. During puberty, the ovaries start to get active. They make more estrogen and other hormones, which are body chemicals. The hormones cause body changes, like growing breasts. They also spark the start of your menstrual cycle, causing you to get your period (usually in about two or three years). Once a month, the ovaries will release one egg (ovum). This is called ovulation.

The egg moves along a fallopian tube, which connects the ovary to the uterus. The uterus — or womb — is where a baby would grow. It takes several days for the egg to get to the uterus.

As the egg travels, estrogen causes the lining of the uterus (called the endometrium) to become thick with blood and fluid. This makes the uterus a good home for a baby. You will get pregnant if you have sex with a male and his sperm joins the egg (called fertilization) on its way to your uterus.

If the egg doesn’t become fertilized, it will be shed along with the lining of your uterus during your next period. But don’t look for the egg — it’s too small to see!

The vagina is a hollow canal or tube that can grow wider to deliver a baby that has finished growing inside the uterus. The opening of the vagina is covered by the hymen, which is a thin piece of tissue that has one or more holes in it. Sometimes a hymen is stretched or torn when you use a tampon or during a first sexual experience, but this does not always happen; sometimes the hymen stays the same. If it does tear, it may bleed a little bit.

The cervix is the narrow entryway in between the vagina and uterus. The muscles of the cervix are flexible so that it can expand to let a baby pass through during childbirth.

Your reproductive system: On the outside

The external reproductive system.Outside of the body, the vulva covers the entrance to the vagina. The vulva has five parts: mons pubis, labia, clitoris, urinary opening, and vaginal opening.

The mons pubis is the mound of tissue and skin just below your stomach. This area becomes covered with hair when you go through puberty.

The labia are the two sets of skin folds (often called lips) on either side of the opening of the vagina. The labia majora are the outer lips, and the labia minora are the inner lips. It is normal for the labia to look different from each other.

The labia minora cover a small sensitive bump called the clitoris, which is at the bottom of the mons pubis. Below the clitoris is the urinary opening, which is where your urine leaves the body. Below the urinary opening is the vaginal opening, which is the entry into the vagina.

Learn more about how your reproductive system works during your period.


Content last reviewed October 13, 2010
Page last updated October 31, 2013

U.S. Department of Health and Human Services, Office on Women's Health.