uterus
The Uterus and Cervix The uterus is the muscular organ that nourishes and supports the growing embryo see Figure 27.14 . Its average size is approximately 5 cm wide by 7 cm long approximately 2 in by 3 in when a female is not pregnant. It has three sections. The portion of the uterus superior to the opening of the uterine tubes is called the fundus. The middle section of the uterus is called the body of uterus or corpus . The cervix is the narrow inferior portion of the uterus that projects into the vagina. The cervix produces mucus secretions that become thin and stringy under the influence of high systemic plasma estrogen concentrations, and these secretions can facilitate sperm movement through the reproductive tract.