Repro #4
Thur 03/27/03 10am
Dr. Wordinger
M. Jones
Proscribe Samera Kasim
Page 1 of 5
FEMALE REPRODUCTIVE HISTOLOGY 2
I.
Uterus
A. Introduction
1. The uterus functions to receive the developing embryo.
2. Nourishes the embryo prior to attachment.
3. Establishes a favorable environment for attachment and takes part in the
formation of the placenta.
a) Selectin on embryo cells recognizes receptors on the uterus, allowing
the blastocyst to attach.
4. Participates in expulsion of the fetus at parturition.
5. Divided into fundus, body, and cervix.
B. Uterine Layers
1. Perimetrium - a serosa or adventitia.
2. Myometrium - smooth muscle plus larger blood vessels.
3. Endometrium - glandular, secretory lining.
a) Sloughs off during menses.
C. Myometrium
1. Four layers can be distinguished according to the direction and disposition
of the smooth muscle.
2. Goes through a period of growth during pregnancy and a reduction in size
after pregnancy.
3. Non-pregnant state - myometrium is constantly undergoing shallow
contractions without sensations.
a) may be exaggerated during sexual stimulation or during menstruation.
4. Pregnant state - progesterone inhibits myometrial contractility.
a) progesterone declines at parturition and oxytocin and prostaglandins
stimulate contraction.
b) So, high progesterone levels = low contractility
c) Oxytocin is high at parturition
d) Prostaglandins are released from the pituitary
D. Endometrium
1. Endometrium consists of a surface epithelial layer and underlying
connective tissue.
a) surface epithelium invaginates into the myometrium to form numerous
uterine glands.
b) connective tissue usually called the endometrial stroma.
2. Surface epithelium is simple columnar secretory cells with scattered ciliated
cells.
a) uterine glands are simple tubular with bifurcations.
(i) Ie. Not much branching
b) glandular secretion is called "uterine milk".
(i) A clear-like fluid
(ii) Nutrients for blasocyst before it attaches.
Repro #4
Thur 03/27/03 10am
Dr. Wordinger
M. Jones
Proscribe Samera Kasim
Page 2 of 5
3.
Endometrial stromal tissue resembles mesenchyme with irregularly stellate
cells with large, ovoid nuclei.
a) Mesenchyme is undifferentiated connective tissue
b) Embryonic in appearance probably because it breaks downs and
rebuilds so often.
4. Endometrium is under the hormonal control of the ovary.
E. Menstrual Cycle
1. Introduction
a) the ovarian hormones (estrogens and progesterone) cause the
endometrium to undergo cyclic, structural changes.
(i) They control the morphology and physiology of the endometrium
(ii) Ex: 17-B estradiol
b) cycles begin at puberty (12-15 years) and continue until menopause
(45-50 years).
c) various phases of the menstrual cycle: proliferative, secretory and
menstrual.
2. Proliferative Phase
a) preceded by the menstrual phase and occurs between days 5-14.
b) takes place during ovarian follicular development.
c) basal (basalis) layer of the endometrium remains following
menstruation and proliferates. Uterine gland cells proliferate, migrate
to the surface and reconstitute the epithelium.
d) glands are straight and narrow at end of the phase.
e) coiled arteries are elongated and convoluted.
(i) Aka Spiral arteries
f) Estradiol secreted from the follicle is prominent and endometrial regrowth is
occurring.
3. Secretory or Luteal Phase
a) begins at ovulation and is dependent upon progesterone produced by
the corpus luteum.
b) There are high levels of progesterone, low estradiol levels
c) lasts from the 15th to the 28th day of the cycle.
d) uterine glands become tortuous, dilate and secrete uterine milk.
e) Endometrium reaches its maximum thickness.
f) elongation and convolution of the coiled arteries continue and extend
into the superficial portion of the endometrium.
g) progesterone stimulates the glands to secrete glycoproteins that will be
the major source of embryonic nutrition before implantation occurs.
4. Premenstral Phase
a) Often not a phase addressed by textbooks.
b) More a histological phase than physiological; can be detected
histologically, but is not necessarily able to be noticed physiologically.
c) Contraction of the arteries, leading to ischemic regions in the
functionalis is indicative of the pre menstral phase.
Repro #4
Thur 03/27/03 10am
Dr. Wordinger
M. Jones
Proscribe Samera Kasim
Page 3 of 5
5.
d) The entire endometrial layer is still present; any shedding of the layer
would indicate entry to the menstral phase
Menstrual Phase
a) Don’t confuse this with “menstral cycle.” The Cycle is 28 days, while
the phase is 1-4 days within the cycle.
b) beginning of menstrual blood signals the beginning of the menstrual
cycle.
c) this phase lasts 1-4 days.
d) at the end of the secretory phase the walls of the coiled arteries contract
thus causing ischemia and necrosis of the endothelium.
(i) Again, this could be considered the premenstrual phase as long as
the entire endometrial layer is present.
e) occurs when implantation fails and estrogen and progesterone levels
fall.
f) desquamation of the endometrium and rupture of blood vessels takes
place.
g) by the end of this phase only the basal layer of the endometrium
remains.
h) proliferative phase then gradually restores the endometrium.
II. Cervix
A. Introduction
1. Narrow segment of the uterus and major area of adenocarcinoma.
a) Usually found in the transition area between the uterus and cervix
b) Determined by pap smear with will show nuclei that are much larger than
normal
c) Normal nuclei are VERY tiny, seen as a tiny dot.
d) Cancerous cells may have nuclei that are ½ the size of the cell
e) Some smears may show early signs of cancer and should be watched very
closely with yearly exams
f) At times, the “pre cancerous” cells don’t become cancerous for 20 years (+)
2. Wall of the cervix is continuous with uterus but is not primarily smooth
muscle, thus doesn’t contract.
a)
B. Histology
1. Mucous membrane is folded and consists of epithelium (simple columnar
epithelium) and connective tissue lamina propria.
2. Numerous large branch tubular glands present which consist of tall mucus
secreting columnar cells.
3. External aspect of cervix bulges into lumen of vagina and is covered by
stratified squamous epithelium.
C. Histophysiology
1. Cervix dilates at parturition to accommodate fetus.
Repro #4
Thur 03/27/03 10am
Dr. Wordinger
M. Jones
Proscribe Samera Kasim
Page 4 of 5
2.
3.
Smooth muscle is not a major component of the cervical wall nor are elastic
fibers.
Relaxin "softens" the cervix by increasing blood supply and tissue fluid
content.
a) Relaxin brings water into the Connective tissue stroma to “soften” the
cervix
III. Vagina
A. Introduction
1. Consists of mucosa, muscular layer and adventitia.
a) a prolapsed uterus can become keratinized
b) any mucus covered surface can become keratinized when exposed to the
outside environment
2. Extends from the cervix to the vestibule.
B. Histology
1. Mucosa consists of stratified squamous epithelium and a lamina propria.
a) normally no keratinization occurs; glycogen is present in the cells.
b) no glands are present.
(i) The fluid present in the vagina is from the cervix
c) acidity of vagina due to fermenting activity of bacteria on glycogen
released into the lumen when cells desquamate.
2. Muscular layer consists of smooth muscle oriented in interlacing bundles.
a) some are arranged circularly while other are longitudinal.
3. Adventitia consists of dense connective tissue containing an extensive
venous plexus, sensory receptors and nerve fibers.
4. Lamina Propria and adventitia are rich in elastic fibers.
Repro #4
Thur 03/27/03 10am
Dr. Wordinger
M. Jones
Proscribe Samera Kasim
Page 5 of 5
IV. Mammary Gland
A. Introduction
1. Modified sweat glands (e.g. cutaneous) which produce an exocrine
secretion by the apocrine mechanism.
a) Consists of the budding of the cell surface which break off and produce
a free floating secretory gland
2. Compound tubuloalveolar gland with irregular lobes.
a) each lobe is separated by dense connective tissue and much adipose
tissue.
b) each lobe has a lactiferous duct which emerges in the mammary papilla
(nipple).
B. Inactive Mammary Gland
1. Intralobular connective tissue is dense and abundant and contains varying
amounts of adipose tissue.
2. Ductal elements lined by epithelial cells are present.
3. Alveoli are small and not numerous.
4. secretory units are present but are not active
C. Lactating Mammary Gland.
1. Soon after parturition, the mammary gland begins active secretion of milk
rich in fat, sugar and proteins.
a) Colosturm – first milk production
2. Alveoli become dilated with milk and have a low epithelium.
3. Estrogens and progesterone cause growth of the duct system at puberty.
4. Pregnancy - continuous and prolonged secretion of these hormones and
placental lactogen and adrenal corticoids.
5. Oxytocin release from the pars nervosa stimulates myoepithelial cell
contraction and promotes "milk let-down".
6. Plasma cells in the connective tissue surrounding the alveoli secrete IgA
into the milk, providing the newborn with passive immunity.