Final answer:
The fibrous tube referred to is the vagina, a muscular canal serving as the entry and exit to the female reproductive tract.
Step-by-step explanation:
The fibrous tube that connects the uterus to the outside of the body is called the vagina. The vagina is a muscular canal that serves as the entrance to the reproductive tract. During childbirth, the vagina expands to accommodate the baby as it is pushed out of the body from the uterus. It is also through the vagina that menstrual flow leaves the body. The uterus itself is connected to the Fallopian tubes, also known as uterine tubes, whose infundibula lie close to the ovaries with fimbriae that help guide the oocyte into the tubes. However, it is the vagina that provides the direct passage to the external environment.