What is the cervix?

The cervix is part of a woman's reproductive system. It's in the pelvis. The cervix is the lower, narrow part of the uterus (womb).
The cervix is a passageway:
• The cervix connects the uterus to the vagina. During a menstrual period, blood flows from the uterus through the cervix into the vagina. The vagina leads to the outside of the body.
• The cervix makes mucus. During sex, mucus helps sperm move from the vagina through the cervix into the uterus.
• During pregnancy, the cervix is tightly closed to help keep the baby inside the uterus. During childbirth, the cervix opens to allow the baby to pass through the vagina.

What is cancer?

Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body.

Normal cells grow and divide to form new cells as the body needs them. When normal cells grow old or get damaged, they die, and new cells take their place.
Sometimes, this process goes wrong. New cells form when the body does not need them, and old or damaged cells do not die as they should. The buildup of extra cells often forms a mass of tissue called a growth or tumor.

Growths on the cervix can be benign or malignant. Benign growths are not cancer. They are not as harmful as malignant growths (cancer).
• Benign growths (polyps, cysts, or genital warts):
o are rarely a threat to life
o don't invade the tissues around them
• Malignant growths (cervical cancer):
o may sometimes be a threat to life
o can invade nearby tissues and organs
o can spread to other parts of the body
Cervical cancer begins in cells on the surface of the cervix. Over time, the cervical cancer can invade more deeply into the cervix and nearby tissues. The cancer cells can spread by breaking away from the original (primary) tumor. They enter blood vessels or lymph vessels, which branch into all the tissues of the body. The cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues. The spread of cancer is called metastasis. See the Staging section for information about cervical cancer that has spread.
(source: http://emedicine.medscape.com/article/)