Illustration of a fallopian tube, or oviduct (5), and an ovary (3) of the female reproductive system. Every month one of the ovaries releases an egg (ovulation), which is received by the adjacent fallopian tube. The egg travels along the tube to the uterus, where, if fertilised, it will implant in the endometrium and grow. If no egg is fertilised the endometrium is shed as a period. From 'Traite d'Anatomie Humaine', Vol. 4 (1905) by French anatomist Leo Testut (1849-1925).