The uterus is a hollow, muscular organ in the female reproductive system. It is located in the pelvis, between the bladder and the rectum. The primary function of the uterus is to nurture a fertilized egg, allowing it to develop into a fetus during pregnancy. It has a thick lining that sheds during menstruation if no pregnancy occurs. The uterus has different parts, including the body, cervix, and fundus. The cervix is the lower part that opens into the vagina, while the fundus is the upper rounded section. Understanding the uterus is essential for women's health, as it plays a crucial role in reproduction.