Female Reproductive System Histology Flashcards
What is the exocrine function of the ovary?
egg production and cytogenic secretions
What is the endocrine function of the ovary?
estrogen production
progesterone production
What are the functions of the oviduct (or fallopian tube)?
ovum pick-up and transport
sperm transport
site of fertilizaiton
egg nourishment
unfortunately, also a conduit for transmission of infectious agents into the peritoneal cavity
What are the function sof the uterus?
- implantation site for conceptus
2. contributes to formation of placenta if pregnancy occurs
What are the functions of the placenta?
nourishment of the fetus
selective exchange of material between fetus and mother
provides a fluid environment/cushion for developing fetus
hormonal functions
What suspends the ovaries?
the mesovarium of the broad ligament
What covers the outside of the ovary?
the germinal epithelium made from peritoneal covering
What are the two zones of the ovary?
medulla and cortex
What zone has all the follicles?
the cortex
the medulla mainly has the blood vessel, lymph and nerves
What layer is immediately under the germinal epithelium?
the tunica albuginea
it’s a dense fibrous connective tissue layer
What embryological structure gives rise to the primordial germ cells in the female?
yolk sac
About how many oogonia develop initially?
1x10^6
About how many primordial and primary follicles are present at the onset of puberty?
400,000
How many eggs will eventually mature and ovulate during a woman’s lifetime?
400-500
Are the prmordial germ cells that migrate to the ovary diploid or haploid?
diploid (have 46 chromosoma)
What cells surround the primordial germ cell in the ovary?
the follicular cells
At what developmental age do the primordial oogonia begin to enlarge and become primary oocytes?
third fetal month
What cell cycle stage do the primary oocytes become stuck in?
the primordial oogonia enlarge and start meiosis I, only to be halted in prophase I
How long will the primary oocytes remain in prophase I?
until just prior to ovulation
How many oocytes finish maturation per month
typically only 1
At what stage does the secondary oocyte become arrested?
metaphase II
Describe the follicular cells in a primordial follicle? What are they maybe derived from? They have receptors for what hormone?
has a single layer of flattened cells
maybe derived from germinal epithelial cells
have FSH receptors
Describe the follicular cells of the primary follicle. What are they called now?
They become taller - columnar (unilaminar primary follicle) and also eventually multiply so the layer becomes stratified (multilaminar primary follicle)
they are now called granulosa cells
What do the stromal cells begin to develop to surround the granulosa cells?
theca folliculi
which will eventually divide into a theca intera and a theca externa
What is the gel-like neutral protein that starts to be formed by the granulosa cells and oocyte in the primary follicle stage?
the zona pellucida
FOrmation of what differentiates a primary follicle from a secondary follicle?
antral space formation - begin as small spaces between the granulosa cells, eventually these small spaces become confluent to form the antrum
What is the antral space filled with?
liquor folliculi (has GAGs, plasma proteins, gonadal steroid hormones, proteoglycans, FSH, inhibin, elecrolytes, etc.)
What do the granulosa cells begin to form around the oocyte in the secondary follicles?
the cumulus oophorus
Describe the theca interna.
it’s a highly vascular, epithelioid region of stromal cells just outside the basement membrane of the follicle
What do the theca interna cells produce?
androgens, which are released intot he antrum with the follicular fluid
Describe the theca externa
region beyond the theca interna made of fusiform cells and collagen
no known secreotry function
somewhat resemble smooth muscle
What is another term for a mature follicle?
Graafian Follicle
Total maturation time for a follicle requires how long?
about 3 months
In the mature follicle, what is the term for the granulosa cells that are in direct contact with the egg and those that radially arrange around the zona pellucida?
corona radiata
What hormone signals the final maturation of the egg in the mature follicle?
LH
What is produced when the primary oocyte completes meiosis I?
the first polar body
What forms during ovulation to allow the egg to rupture out?
the stigma
the follicular wall adjacent to the tuna albuginea thins out via decreased blood flow and maybe protease release
After the ovum ruptures out of the follicle, what do the remnants of the follicle rapidly reorganize to form?
the corpus luteum
What does FSH do in regards to granulosa cells?
It stimulates their growth and promotes their synthesis of estrogen
FSH also stimulates receptors for what?
LH
What does LH do?
- stimulates thecal cell growth and androgen production
2. stimualtes progesterone production in the granulos acells
What happens to the androgens produced by the thecal cells?
the granulosa cells have aromatase that will convert it to estrogen
the dominant follicle becomes a very efficient secretor of what hormone?
estrogen
What are the two main cell components of the corpus luteum?
granulosa components become the granulosa lutein cells
theca interna components become the theca lutein cells
What do the granulosa lutein and theca lutein cells produce?
progesterone and some estrogen
Which corpus luteum always frms? How big does it get? How long does it last?
the corpus luteum of menstruction
reaches 1.5-2 cm
if the embryo does not get fertilizes, it will involute in about 14 days
What is the scar tissue from this involution called?
the corpora albicans (white scar)
What is the other corpus luteum?
the corpus luteum of pregnancy
How big does that one get?
5 cm
What maintains the corpus luteum of pregnancy?
maintained by hCG produced by the trophoglast
How long does the corpus luteum of pregnancy persist?
through the first trimester and then slowly involutes
Estrogen is primarily produced by what in this system?
the growing follicle
What are some of the functions of this estrogen?
- induces maturation of female reproductive tract and mammary glands
- directs repair of uterus following menstruation
- influences growth of mammary gland sin pregnancy
Progesterone is primary produced by what?
the corpus luteum
What are the functions of the progesterone?
- causes uterine glands to secrete
- prepares uterus for implantation of the fertilized ovum
- aids in the growth of mammary glands
- inhibits uterine contractions
What produces relaxin?
the corpus luteum and decidual cells of the placenta
What are the actions of relaxin?
- inhibits contractions of myometrium during pregnancy
- promotes dilation of cervix
- loosens symphysis pubis in some species
What percentage of follicles involute without ever completely maturing?
over 99%!
In general terms, describe what happens in follicular atresia.
- the ovum degenerates first
- follicular cells then degenerate
- theca interna cells degenerate last
- entire structure is replaced by scar tissue
What stage of development are the follicles when they become atretic?
they can be in any developmental stage (besides mature obviously)
On to the fallopian tube or oviduct….
1
What are the three divisions of the oviduct?
ampulla
isthmus
intramural portion
What extra portion is included in the ampulla? What is its purpose?
the infundibulum
it’s the funnel-shaped open end with fimbria that serve to catch the released ova
Describe the mucosa of the ampulla?
mucosa with elavorate branching folds
the epithelium is simple columnar ciliated
What are the two types of epithelial cells in the ampulla?
- ciliated cells to transport the egg toward the uterus
2. secretory cells (peg cells) for tubal fluid production, proteins, and ions
How do the ciliated cells respond to estrogen?
they will increase the number of cilia
How will the secreoty cells respond to progesterone and estrogen?
progesterone - increase in height and number
estrogen - increase secretory activity
How does the mucosa of the isthmus compare to that of the ampulla?
- fewer folds than in the ampulla (unbranched)
- reduced numbers of ciliated cells, but secretory cells are still quite active
- smaller diameter
How does the intramural segment mucosa compare to that of the ampulla and isthus?
- almost no folds
- no cilia - just secretory cells
- smallest diameter
What additional layer is included in all those mucosal folds?
lamina propria
Describe the muscularis of the fallopian tube.
has an inner circulaer layer of smooth muscle which is very thick
outer longituinal layer is thin and incomplete
What does that smooth muscle allow for in the fallopian tube?
allows for tubal peristalsis to help embryo transport through the isthmus during the luteal phase
What are the three structural divisions of the uterus?
body
fundus
cervix
What are the three uterine wall layers from outside to inside?
perimetrium
myometrium
endometrium
Describe the epitheliuum of the endometrium.
- simple columnar epithelium
- surface cells are ciliated at the opening of simple tubular glands
there is a lamina propria just beyond that
What are the two zones of endometrium?
basal layer
functional layer
Describe the basal layer. Why is it so important?
it’s the deepest layer and is relatively narrow
the glands here do not cycle thorough the menstrual cycle an dare not shed during menstruation or parturition
they are responsible for regeneration of the functional layer!
What are the two subdivisions of the functional layer?
superficial compact layer
deep spongy layer
Which of the functional layer subdivisions comprises the bulk of the endometrium?
the deep spongy
Which one becomes really edematous before sloughing?
the deep spongy
How many layers comprise the myometrium?
three
the cells interweave in a complex manner which makes them hard to differentiate
Where in the uterus is the smooth muscle myometrium reduced?
in the cervix
How do the muscle fibers respond to the menstrual cycle?
the fibers are shortest during the first week after menstruation
fibers are longest in the fourth week of the cycle
During pregnancy, does the myometrium respond largely by hypertrophy or hyperplasia?
mostly hypertrophy, but some of both
Describe the blood supply in order?
uterine arteries (in broad ligament) arcuiat arteries (in myometrium) Straight arteries (stratum basale) Spiral (or helical) arteries (stratum functionale) capillaries
How long does the menstrual cycle last on average?
29 days
but can range from 21 to 40
What are the 5 phases of the menstrual cycle?
proliferative phase secretory phase premenstrual (ischemic) phase menstrual phase repair phase
What stage is the most variable in length?
proliferative
In general terms, when does the proliferative phase occur?
Day 7-14 of the cycle (beginning at the end of the menstrual flow)
What hormone induces the proliferative phase?
estrogen (from the androgens of the theca converted to estrogen by granulosa aromatase)
How much thicker does the endometrium become during the proliferative phase?
undergoes a 2-3 fold increase (entirely because of the functional layer)
Is the increase in thickness due to numerous mitoses in the glands or in the stroma?
trick question - both
Describe what happens to the tubular glands during the proliferative phase.
- increase in number
- increase in length (remain straight)
- accumulate glycogen
Describe what happens to the coiled arteries during the proliferative phase.
they elongate, but do not reach the surface
The secretory phase tends to occur during what days of the cycle?
15-26
What is the primary event that occurs in the secretory phase?
ovulation
Ovulation precipitates the formation of the corpus luteum, which does what to the hormone profile?
progesterone secretion increases dramatically
estrogen secretion also increases slightly
Endometrial thickening continues during the secretory phase, but what is it driven by now?
stromal edema rather than mitoses
Describe what happens to the glands during the secretory phase.
the glands dilate and become saccular and tortuous
cells accumulate glycogen, salts and proteins
Why all the glycogen accumulation?
It’s essentially preparing the uterus to be a good place for a fertilized egg to implant
What happens to the coiled arteries during the secretory phase?
they elongate and become convoluted
they extend into the superficial portion of the endometrium
During the secretory phase, stromal cells will continue to accumulate glycogen and lipid dropletes. What will they form if pregnancy occurs
the decidua of the placenta
What stage occurs after the secretory phase?
the premenstrual (ischemic) phase
What does does the premenstrual phase occur on?
27-28
What happens to the corpus luteum during the premenstrual phase?
it regresses
What happens to the coiled arteries in response to the decline in progesterone?
they will start to constrict intermittently
What happens due to this intermittent constriction?
the vessels become weak and you start to see small stromal hemorrhages with seepage into the uterine lumen
Eventually this vascular constriction becomes permanent. What does this lead to?
the terminal portions become anoxic and necrose
endometrium detachment begins
arterioles will bleed directly onto the denuded surface
What occurs after the secretory phase?
the menstrual phase - days 1-4
WHat happens in the menstrual phase?
duh…you menstruate
the functional layer of the endometrium undergoes completed necrosis and shedding
True or false: menstrual blood does not clot.
true - there is fibrinolysin that prevents clotting
the “clots” you can see are RBC aggregates
What happens after the menstrual phase?
the repair phase - days 5-6
What happens during the repair phase?
the denuded surface is re-epithelialized from the glands and stroma
the coiled arteries being to re-grow
Is the mucosa of the cervix shed during menstruation?
no
Instead of menstruation, what is the response of the cervical mucosa to the menstrual cycle?
alters the type of secretion
Describe the epithelium of the cervical mucosa
simple columnar with basal nuclei, pale cytoplasm
they secrete mucous
some cells are ciliated
What happens to the epithelium at the external cervical os?
There is an abrupt transition from simple columnar to stratified squamous non-keratinizing epithelium
this is the squamocolumnar junction
Why is the squamocolumnar junction important clinically?
this is where most carcinomas of the cervix develop
Are there coiled arteries in the lamina propria of the cervix?
nope
Describe the myometrium of the cervix?
it’s comprised primarily of dense connective tissue - remember that the smooth muscle things out…
there is some smooth muscle present, but irregularly arranged
There are tons of mucosal glands in the cervix. they are large and branching. What happens if their ducts become occluded?
Nabothian cysts - usually not pathological, but may need surgical removal if they block the os
Describe the cervical mucus produced under the high estrogen stimulation of the secretory phase just prior and during ovulation?
it’s estrogenic mucus with low viscocity
this permits sperm migration
Describe the cervical mucus during the rest of the cycle?
Gestrogenic mucus
high viscosity to retard sperm and particle passage
Describe the epithelium of the vagina.
stratified squamous non-keratinizing
The cells of the vagina become loaded with glycogen. Why is this important?
the lactobacilli (normal microflora of the vagina) consume it to produce lactic acid, which causes an acidic pH in the vagina to hinder growth of other pathogens
What will happen to the mucosa of the vagina during the follicular phase?
- proliferation and hypertrophy of basal cells
- glycogen synthesis and storage
- exfoliated cells are eosinophilic and reach maximal in number during the periovulatory period
What will happen to the mucosa of the vagina during the luteal phase?
- decrease in epithelial height
- exfoliated cells decrease in number and become basophilic
- leukocytes appear and are shed into the lumen
Describe the lamina propria of the vagina.
moderately dense connective tissue many leukocytes elastic fibers numerous blood vessels in deeper layers numerous transverse folds (rugae) no glands
If there are no vaginal glands, how does it become lubricated?
cervical secretions and some fluid transudation from vaginal blood vessels
Describe the muscularis of the vagina
interlacing bundles of smooth muscle with a thin inner circular group and a thick outer longitudinal group
What skeletal muscle forms a type of sphincter around the ostium of the vagina?
the bulbocavernosus
