fallopian tube (fəlōˈpēən) [key], either of a pair of tubes extending from the uterus to the paired ovaries in the human female, also called oviducts, technically known as the uterine tube. At one end the long, slender fallopian tube opens into the uterus; the other end expands into a funnel shape near the ovary. The epithelium that lines the tube is covered with cilia that beat continuously toward the uterus. When an ovum is expelled into the peritoneal cavity from the ovary during ovulation, it is propelled into the wide-mouthed opening of the fallopian tube, through the tube, and into the uterus by the wavelike motion of the cilia. If the ovum is fertilized, an event that normally takes place in the fallopian tube, and the embryo (fertilized ovum) implants in the tube, or another area outside the uterus, an ectopic pregnancy occurs. About 98% of ectopic implantations occur in the tubes, but other sites include the abdomen, ovary, and cervix. Immediate surgical removal of the products of conception is necessary to prevent hemorrhage and other complications resulting from ectopic pregnancy. The fallopian tubes are also the site of the most common surgical procedures used to prevent conception or cause infertility in women. Usually the tubes are tied off in a procedure known as tubal ligation, although they are also sometimes excised or occluded by other methods. See reproductive system; uterus.