The Growth & Development II BIBLE
Case 1
The female reproductive system consists of the lower genital tract (vulva and vagina) and the
upper tract (uterus and cervix with fallopian tubes and ovaries).
The female vulva describes the external genitalia. It includes the mons pubis, labia majora /
minora, clitoris, vestibule, vestibular bulb and the greater vestibular glands.
- The mons pubis is the rounded hair-bearing area over the pubic symphysis and pubic
bone. It is formed by adipose connective tissue. Before puberty it is flat, during adolescence hair
forms and it becomes enlarged.
- The labia majora are two prominent, longitudinal folds of skin that extend from the mons
pubis to the perineum. They form the lateral boundaries of the vulva.
- The perineum is the space between the anus and vulva in females, in males it is between
the anus and the scrotum.
- The labia minora are two small cutaneous folds that lie between the labia majora. They
extend from the clitoris down, laterally and back, flanking the vaginal orifice. The upper layer of
each side passes above the clitoris to form a fold, the hood or prepuce, which overhangs the
glands of the clitoris. They are richly innervated and vascularised, have abundant elastic fibres, no
hair follicles.
The vestibule is the cavity that lies between the labia minora. It contains the vaginal and external
urethral orifices and the openings of the two greater vestibules (Bartholin’s) glands and of
numerous mucous, lesser vestibular glands.
- The urethra opens into the vestibule below the clitoris and above the vaginal opening via
the urethral meatus.
- The ducts of the Skene’s glands / lesser vestibular glands open on each side of the
urethra. There function is not understood but are sometime known as the female prostate.
- The bulbs of the vestibule lie on each side of the vestibule. They are two elongated
masses of erectile tissue, which flank the vaginal orifice. During the response to sexual arousal the
bulbs fill with blood, which then becomes trapped, causing erection, this causes the vulva to
expand outward.
- The greater vestibular glands consist of two small bodies that flank the vaginal orifice.
Each opens into the posterolateral part of the vestibule by a duct. They secrete clear or whitish
mucus with lubricant properties. They are stimulated by sexual arousal.
- The clitoris is an erectile structure partially enclosed by the anterior bifurcated ends of the
labia minora, the prepuce.
,The vagina is a fibromuscular tube that extends from the vestibule to the uterus.
- The part of the vagina surrounding the cervix is called the fornix. It is divided into
anterior, posterior, lateral and medial fornixes. The posterior fornix is deeper than the anterior
fornix.
- The width of the vagina increases as it ascends. In an unexcited state, it is collapsed.
- The anterior wall of the vagina close to the base of the bladder and urethra.
- The posterior wall is separated from the rectum by the recto-uterine pouch superiorly
(Douglas’ pouch), and by moderately loose connective tissue (Denonvillier’s fascia) in its
middle half. In its lower quarter it is separated from the anal canal by the musculofibrous perineal
body.
- The vagina opens externally via an introitus positioned below the urethral meatus. The
size of the introitus varies and is capable of great distension. The hymen is a thin fold of mucous
membrane situated just within the vaginal orifice.
- Natural vaginal bacteria, particularly lactobacillus acidophilus, break down glycogen
into lactic acid. This produces a highly acidic environment.
- The lining of the vagina has many ruggae. Here are no vaginal glands; it is lubricated by
fluid pushed out of capillaries, which permeates the epithelium.
The uterus is an organ situated in the pelvis, between the urinary bladder and the rectum. It lies
posterior to the bladder and anterior to the rectum. It normally flexes anteriorly on top of the
bladder.
- The uterus is divided into two main regions by the isthmus: the body of the uterus
forms the upper-thirds, and the cervix forms the lower third.
- The uterine body is composed of three main layers. These are the endometrium,
myometrium and serosa (or adventitia).
- The endometrium is formed by a layer of connective tissue, which supports a single-
layered columnar epithelium. After puberty, the endometrium varies with the stage of the
menstrual cycle.
,The myometrium is composed of smooth muscle and loose connective tissue, and contains blood
vessels, lymphatic vessels and nerves. The body of the uterus has four muscular layers.
- The uterine body is covered by peritoneal serosa, which continues downwards posteriorly
to cover the supravaginal cervix. The anterior cervix and the lateral surfaces of the uterine body
and cervix are not covered by peritoneum.
The body of the uterus is pear shaped and extends from the fundus superiorly to the cervix
inferiorly.
- Near the upper end, the uterine tubes enter the uterus on both sides at the uterine
cornua.
- The lateral margins of the body are convex, and on each side their peritoneum is reflected
laterally to form the broad ligament, which extends as a flat sheet to the pelvic wall.
- The posterior wall and upper part of the anterior wall are covered by visceral peritoneum.
The lower part of the anterior wall is connected to the bladder.
The upper end of the cervix communicates with the uterine body via the internal os, and the
lower end opens into the vagina at the external os.
- In nulliparous women, the external os is usually a circular aperture, whereas, after
childbirth, it is a transverse slit. The isthmus of uterus forms the upper third of the cervix.
- The external end of the cervix enters the upper end of the vagina, thereby dividing the
cervix into supravaginal and vaginal parts.
- The cervix consists of fibroelastic connective tissue and contains relatively little (10%)
smooth muscle. The elastin component of the cervical stroma is essential to the stretching capacity
of the cervix during childbirth.
- The cervical canal is lined by a deeply folded mucosa with a surface epithelium of
columnar mucous cells.
- The surface of the intravaginal part of the cervix (ectocervix) is covered by non-
keratinizing stratified squamous epithelium, which contains glycogen.
- The squamocolumnar junction, where the columnar secretory epithelium of the
endocervical canal meets the stratified squamous covering of the ectocervix, is located at the
external os before puberty.
- As oestrogen levels rise during puberty, the cervical os opens, exposing the endocervical
columnar epithelium on to the ectocervix. This area of columnar cells on the ectocervix forms an
area that is red and raw in appearance, called an ectropion (cervical erosion).
- It is then exposed to the acidic environment of the vagina and, through a process of
squamous metaplasia, transforms into stratified squamous epithelium. This area is thus known
as the ‘transformation zone’.
- In postmenopausal women, the junction recedes into the endocervical canal.
, The cervix tilts forwards relative to the axis of the vagina (anteversion), and the body of the
uterus tilts forward relative to the cervix (anteflexion).
- In 10 to 15% of women the whole uterus leans backwards at an angle to the vagina and
is said to be retroverted. A uterus that angles backwards on the cervix is described as
retroflexed.
The uterine tubes are attached to the upper part of the body of the uterus, and their ostia open
into the uterine cavity. The tubes pass laterally and superiorly, and consist of four main parts:
intramural, isthmus, ampulla and fimbria.
- The ampulla is the widest portion of the tube. Fertilization typically takes place here.
- The ampulla opens into the trumpet-shaped infundibulum at the abdominal os.
Fimbriae, numerous mucosal finger-like folds 1 mm wide, are attached to the ends of the
infundibulum and extend from its inner circumference beyond the muscular wall of the tube.
-One of these, the ovarian fimbria, is longer and more deeply grooved than the others, and
is typically applied to the tubal pole of the ovary. At the time of ovulation, the fimbriae swell and
extend as a result of engorgement of the vessels in the lamina propria, which aids capture of the
released oocyte. All fimbriae are covered, like the mucosal lining throughout the tube, by a ciliated
epithelium whose cilia beat towards the ampulla.
