FEMALE REPRODUCTIVE SYSTEM
Prof.Dr. Huda Al-Khateeb
Lec. 11
Uterus
It is a pear-shaped organ with thick, muscular walls. It has 3
parts
1.Body: largest part, the body
2. Fundus: upper dom-shape part
3. Cervix: lower most part
The uterine wall has three major layers:
1.The endometrium (mucosa): the inner most layer
2.The myometrium (muscular layer)
3.The perimetrium : outer connective tissue layer
Endometrium
Composed of
1.Simple columnar epithelium ulternating ciliated and
secretory
2.Lamina propria: loose connective tissue (mostly cellular).
Contains uterine glands
Uterine glands
penetrate the full thickness of the endometrium
They are strait in the proliferative phase of menstrual cycle
and tortous in the secretory phase
Endometrium is subdivided into two zones.
(1) The basal layer adjacent to the myometrium, contains
highly cellular lamina propria and the deep basal ends of the
uterine glands.
(2) The superficial functional layer (or functionalis)
contains more spongy and less cellular lamina propria,
richer in ground substance, most of the length of the glands,
as well as the surface epithelium.
The functional layer undergoes profound changes during
the menstrual cycles, but the basal layer remains relatively
unchanged
Endometrium blood supply
The blood vessels supplying the endometrium are of special
significance in the periodic sloughing of the functional layer
during menses.
1.Arcuate arteries in the middle layers of the myometrium
send two sets of smaller arteries to the endometrium
2. straight arteries, which supply only the basal layer
3. long, progesterone-sensitive spiral arteries, which extend
farther and bring blood throughout the functional layer.
Spiral arteries branch with numerous arterioles supplying a
rich capillary bed that includes many dilated, thin-walled
vessels called vascular lacunae
Myometrium
The myometrium (Gr. myo, muscle, + metra, uterus), the
thickest layer of the uterus, is composed of bundles of
smooth muscle fibers that form four interwoven, poorly
defined layers
During pregnancy, the myometrium goes through a period
of extensive growth involving both hyperplasia (increasing
the number of smooth muscle cells) and hypertrophy
(increasing cell size). During this growth, many of the
smooth muscle cells also actively synthesize collagen,
strengthening the uterine wall
After pregnancy, uterine smooth muscle cells shrink and
many undergo apoptosis, with removal of unneeded
collagen, and the uterus returns almost to its prepregnancy
size
Menstrual Cycle
From the time of puberty until menopause, the
endometrium to undergo cyclic structural changes during
the menstrual cycle.
The duration of the menstrual cycle is variable but averages
28 days
Phases of the menstrual cycle
1.The menstrual period of the cycle lasts 3–4 days on
average.
2.The proliferative phase, is of variable length, 8–10 days on
average
3.The secretory phase begins at ovulation and lasts about 14
days.
Proliferative (Follicular) (Estrogenic)
phase
After the menstrual phase, the uterine mucosa is relatively
thin (about 0.5 mm).
Ovary is characterized by folliculogenesis and estrogen
secretion
Estrogens
act on
the
endometrium, inducing cell
proliferation and reconstituting the functional layer lost
during menstruation.
During the proliferative phase, the uterine glands are
relatively straight tubules with narrow, nearly empty
lumens.
At the end of the proliferative phase, the endometrium is 2–
3 mm thick.
Secretory(Luteal)(Progesteronic)phase
Ovary shows corpus luteum formation and progesterone
secretion.
Progesterone stimulates epithelial cells of the uterine glands
and they become highly coiled during this period.
The endometrium reaches its maximum thickness (5 mm)
Menstrual Phase
Ovary shows corpus albicans formation and reduction of
estrogen and progesterone
Endometrium reveals sheding of the functional layer
Placenta
Composed of
1.Fetal part- includes Amnion and Chorionic plate
2.Villi and intervillus space
3.Maternal part
The placenta is also an endocrine organ, producing HCG,
chorionic thyrotropin, chorionic corticotropin, estrogens,
progesterone, and other hormones
Uterine Cervix
The cervix is the lower, more cylindrical part of the uterus
and it differs in histologic structure from the rest of the
uterus.
It is composed of 2 parts
(1)Endocervix – cervical canal, ext. os and int. os
(2)Ectocervix – pulging into vagina
The endocervix is lined by a mucus-secreting simple
columnar epithelium on a thick lamina propria.
The
ectocervix
is
lined
by
stratified
squamous
nonkeratenized epithelium.
A distinct junction, or transformation zone, occurs where
the simple columnar epithelium undergoes an abrupt
transition to stratified squamous epithelium
The endocervical mucosa contains many branched cervical
glands, which produce mucus.
However, this mucosa is affected histologically much less
than the endometrium and it does not shade during
menstruation
The deeper, middle layer of the cervix has little smooth
muscle and consists mainly of dense connective tissue
Cervical secretions change cyclically.
At the time of ovulation, the mucous secretions are
maximal, watery, and facilitate movement through the
uterus by sperm. In the luteal phase high progesterone levels
cause the mucous secretions to become viscous and hinder
the passage of both sperm and microorganisms into the body
of the uterus. During pregnancy, the cervical glands
proliferate and secrete abundant, highly viscous mucus
which forms a plug in the endocervical canal
Before parturition the cervix dilates greatly and softens due
to intense collagenolytic activity in the stroma
Vagina
The wall of the vagina lacks glands and consists of three
layers
1.mucosa: stratified squamous epithelium and lamina
propria
2.muscular layer
3.adventitia.
Mucus covering the lumen of the vagina is produced by the
glands of the uterine cervix
The epithelium of the vaginal mucosa is stratified squamous
non-keratinized, with a thickness of 150–200 m in adults.
Stimulated by estrogens, the epithelial cells synthesize and
accumulate glycogen. When the cells desquamate, bacteria
metabolize glycogen to lactic acid, causing a relatively low
pH within the vagina which helps provide protection against
pathogenic microorganisms
The lamina propria of the mucosa is rich in elastic fibers
and has numerous narrow papillae projecting into the
epithelial layer.
The
vaginal
connective
tissue
normally
contains
lymphocytes and neutrophils in relatively large quantities.
The vaginal mucosa itself has few sensory nerve endings
The muscular layer of the vagina is composed mainly of two
indistinct layers of smooth muscle,
1.inner circular bundles next to the mucosa
2.outer thicker longitudinal bundles near the adventitial
layer.
The dense connective tissue of the adventitia is rich in elastic
fibers, making the vaginal wall strong and elastic while
binding it the surrounding tissues.
This outer layer also contains an extensive venous plexus,
lymphatics, and nerves
Mammary Glands
Each mammary gland consists of 15–25 lobes of the
compound tubuloalveolar type whose function is to secrete
milk to nourish newborns.
Each lobe, separated from the others by dense connective
tissue with much adipose tissue, is a separate gland with its
own excretory lactiferous duct. These ducts emerge
independently in the nipple, which has 15–25 openings
The lactiferous sinuses are lined with stratified cuboidal
epithelium
the lining of the lactiferous ducts and terminal ducts is
simple cuboidal or columnar epithelium covered by closely
packed myoepithelial cells. Sparse fibers of smooth muscle
also encircle the larger ducts
The histologic structure of the mammary glands varies
according to sex, age and physiologic status (puberty,
pregnancy, lactation, weaning and involution)
Mammary Glands before puberty
The mammary glands in both sexes are composed only of
lactiferous sinuses with small, branching ducts emerging
from these sinuses
Mammary gland during Puberty
In girls undergoing puberty and having higher levels of
circulating estrogens, the breasts increase in size as a result
of adipocyte accumulation in the connective tissue and
increased growth and branching of the duct system
Mammary gland during pregnancy
The mammary glands undergo growth during pregnancy as
a result of the synergistic action of several hormones, mainly
estrogen, progesterone, prolactin, and human placental
lactogen. One result of these hormones is the proliferation of
secretory alveoli at the ends of the intralobular ducts.
The spherical alveoli are composed of cuboidal epithelium,
with stellate myoepithelial cells between the secretory cells
and the basal lamina
Mammary gland during lactation
Following parturition the glandular alveoli of the breasts
increase greatly in size and become very active in milk
production, primarily influenced by prolactin from the
anterior pituitary
Epithelial cells of the alveoli enlarge and engage actively in
synthesis of proteins and lipids for secretion
Proteins are made on rough ER, processed through the
Golgi apparatus and packaged into secretory vesicles, which
undergo exocytosis during merocrine secretion into the
lumen.
Spherical lipid droplets form in the cytoplasm of the
alveolar cells and pass out of the cells into the lumen by the
process of apocrine secretion
When a woman is breast-feeding, the nursing action of the
child stimulates tactile receptors in the nipple, resulting in
liberation of the posterior pituitary hormone oxytocin . This
hormone causes contraction of the smooth muscle of the
lactiferous sinuses and ducts, as well as the myoepithelial
cells of alveoli, resulting in the milk-ejection reflex. Negative
emotional stimuli, such as frustration, anxiety, or anger, can
inhibit the liberation of oxytocin and thus prevent the reflex.
Postlactational Regression in the Mammary
Glands
When breast-feeding is stopped (weaning), most alveoli that
developed
secretory
properties
during
pregnancy
degenerate.
The duct system of the gland returns to its general
appearance in the inactive state before pregnancy.
After menopause, alveoli and ducts of the mammary glands
are reduced further in size and there is some loss of fibro-
blasts, collagen, and elastic fibers in the stroma