The vagina is the organ that receives the male
sperm during intercourse. It also forms the lower
portion of the birth canal, stretching widely during
delivery. In addition, it serves as an excretory duct for
uterine secretions and menstrual flow.
The vagina is a fibromuscular tube capable of great
distention. The canal is approximately 9 cm long and
extends from the uterus to the outside. The vaginal
orifice is partially closed by a thin membrane of tissue
called the hymen. The wall of the vagina consists of
three layers. The inner mucosal layer does not have
mucous glands; the mucous found in the vagina comes
from the glands of the cervix. The middle muscular
layer consists mainly of smooth muscles fibers. At the
lower end of the vagina is a thin band of smooth muscle
that helps close the vaginal opening. The outer fibrous
layer consists of dense fibrous connective tissue
interlaced with elastic fibers. These fibers attach the
vagina to the surrounding organs.
EXTERNAL ACCESSORY ORGANS
Many of the external accessory organs of the
female reproductive system are referred to collectively
as the vulva. The vulva includes the labia majora, the
labia minora, the clitoris, and the vestibular glands
(fig. 1-63). The mammary glands are also considered
an accessory organ of the female reproductive system.
The function of the labia majora is to enclose and
protect the other external reproductive organs. The
labia majora are composed of two round folds of fat
tissue and a thin layer of smooth muscle, covered by
skin. On the outer portion of the labia majora, the skin
has numerous hairs, sweat glands, and sebaceous
glands. The inner portion of skin is thin and hairless.
The labia majora extend from the mons pubis
anteriorly to the perineum (the region between the
vaginal orifice and the anus). The mons pubis is the
pad of fatty tissue beneath the skin, which overlies the
Within the labia majora folds are two smaller
folds, called the labia minora. The labia minora extend
from the clitoris to either side of the vaginal orifice.
The clitoris is a small projectile at the anterior end
of the vulva between the labia minora. It is richly
endowed with sensory nerves that are associated with
the feeling of pleasure during sexual stimulation.
The vestibule is the area enclosed by the labia
minora that includes that vaginal and urethral
openings. The vestibule contains a pair of vestibular
glands, more commonly known as the Bartholin's
glands. The Bartholin's glands lay on each side of the
vaginal opening. The ducts of these glands secrete
fluid that moistens and lubricates the vestibule.
The mammary glands, or breasts, are accessory
organs of the female reproductive system. They
develop during puberty under the influence of the
hormones estrogen and progesterone. The breasts are
responsible for the secretion of milk (lactation) for the
nourishment of newborn infants.
Structurally, the breasts resemble sweat glands. At
the center is a nipple containing 15 to 20 depressions
into which ducts from the lobes of the gland empty.
During pregnancy, placental estrogen and progesterone
stimulate further development of the mammary glands
Figure 1-63.External reproductive organs.