1-3.
INTERNAL GENITALIA
See figure 1-1.
a. Uterus or Womb.
(1) Description/information. The uterus is a hollow, muscular, pear-shaped
organ. It is located in the pelvic cavity between the urinary bladder and the rectum.
During a woman's child-bearing years, the uterus is about 7.5 centimeters long, 5
centimeters wide, and 2.5 centimeters thick. The uterus has three anatomical divisions:
the fundus, the body, and the cervix. The fundus is the upper, convex part of the
uterus. This part is just above the entrance to the uterine tubes. The body is the central
portion of the uterus, and the cervix is the lower, neck-like part of the uterus.
(2) Walls. The walls of the uterus are made up of three layers: the
endometrium, the myometrium, and the parietal peritoneum. The endometrium, the
inner layer, attaches itself to the myometrium layer and lines the uterus. This layer is
sloughed off during menstruation or post- delivery. The middle layer, which is
composed of smooth muscle, is the myometrium. This layer is made up of longitudinal,
circular, and spiral muscular fiber which interlaces. The myometrium is thickest in the
fundus and thinnest in the cervix. During childbirth, this muscle layer is capable of the
very powerful contractions necessary for a normal birth. The third layer, the parietal
peritoneum, is the outer layer which is a serous membrane. This outer layer of uterine
wall is incomplete, covering only part of the uterine body and none of the uterine cervix.
(3) Functions. The uterus has three major functions which occur during
these events: pregnancy, labor, and menstruation. During pregnancy, the uterus holds
the fertilized ovum. The ovum is deposited in the uterus where it grows and develops
through the embryo and fetal stages. During the birth process, the uterus produces
powerful contractions to expel the mature infant. And, finally, during a female's
menstrual phase, the inside lining of the uterus detaches and sloughs off the uterus,
expelling its fluid contents.
b. Uterine Tubes, Fallopian Tubes, or Oviducts.
(1) Description/information. These tubes are known by all three names
listed above. The name commonly used is fallopian tubes. These two tubes extend
from the ovaries to the uterus. An ovum discharged from an ovary passes through one
of these tubes to the uterus. Each tube is about 10 centimeters long (4 inches). The
tube is located between the folds of the broad ligaments of the uterus. The tubes are
attached to the uterus at one end but not attached to the ovaries at the other end. At
the ovary end, the tubes are open, funnel-shaped, and close to the ovary. The funnel-
shaped ends of the tubes are called the infundibulum, and the fringe or finger-like
processes at the tube ends are called fimbriae.
MD0584
1-4