Repro Histology Flashcards
Where are the follicles located in the ovary?
Immature follicles (primordial and primary) generally near the capsule
Later, follicles are futher in- they get too large so they invade the medulla
Is the cortex or the medulla of the ovary paler staining?
Medulla is paler staining
When looking at a cross section of an ovary why do some follicles look empty?
B/c you’re taking a cross section so not every slice will contain the developing ovum
Why may you get a picture of an ovary w/o any follicles
Ovary of a post-menopausal woman
What is the germinal epitheilum?
What lies underneath it?
Simple cuboidal epithelium covering the ovary
-underneath is the tunica albuginea = layer of dense CT
What is the ovarian stroma?
The cellular matrix of the ovarian cortex
Does the ovary have a capsule?
Yes! The capsule of the ovary is made up of the germinal epithelium + tunica albuginea
What stage are oocytes frozen in at birth? About how many are present?
Females are born w/ about 400,000 primordial follicles (earliest stage of oogenesis) and don’t produce any more after birth
-at birth the oocytes are frozen at prophase I (prophase of meiosis I)
What structure represents the earliest stage of oogenesis
Primordial follicle- what females are born with
-oocyte is surrounded by granulosa (= follicular) cells = single flattened layer of epithelial cells
What are follicular cells?
Follicular = granulosa cells = the cells that surround the follicles
- single flattened layer surrounding primordial follicles
- single cuboidal layer surrounding early primary follicles
- multiple (up to 5 or 6) cuboidal layers surrounding late primary follicles
What stage of meiosis is the oocyte in
(a) at birth of the female
(b) at ovulation
(c) at fertilization
Meiosis is segmented in females
(a) at birth the primordial follicle is stuck in prophase I
(b) just before ovulation the oocyte completes meiosis I and gets frozen again in metaphase II- the cytoplasm divides unequally making one daughter cell and the first polar body
(c) the ovum is in metaphase II, then upon ovulation it completes meiosis II
At what stage does FSH/LH become necessary for futher follicular development?
After the primary follicle is mature, the secondary follicle requires FSH (and a little LH) to develop further
What is the theca folliculi?
What are its two layers and what are their function?
Theca folliculi = coat of stroma that develops around the late multilaminar primary follicle
It differentiates into the theca interna (touches the granulosa cells) and the theca externa
- Theca interna = layer of steroid producing cells- produces androstenedione (converted to estradiol by the granulosa cells)
- Theca externa cells are myofibroblast-like and is basically a fibrous CT layer
What is a secondary follicle?
Secondary = Antral follicle
Contains an antrum = fluid filled space
-fluid resembles plasma w/ high concentration of steroids
What is an atretic follicle?
Degenerated follicle
- the zona pellucida often remains present, giving a “rubber band” appearance in the middle
- macrophages come in to clean up the remains of the follicular cells, leaving a CT scar = corpus albicans
Define atresia
Only about 1,000 of the 400,000 follicles mature => the other 399,000 undergo atresia (degeneration)
-rubberband appearance of the remnant of the zona pellucida
What is the corona radiata?
What is the cumulus oophorus?
Coronoa radiata = Ring of follicular cells that remain attached to the ovum even after ovulation
Cumulus oophorus = stalk of follicular cells that attaches the ovum to the follicle
What is the final stage of oocyte development?
GRaafian or mature follicle
- complete antral cavity
- ovum only attached by the cumulus oophorus
- ready to be ovulated
When is the corpus luteum formed? What is composed of?
Corpus luteum forms after ovluation from the remiaining follicular and thecal cells (what is left behind in the ovary)
- it will last about 11-14 days w/o implantation (maintained by LH)
- if implanatation occurs, hCG from the placenta will maintain it
Differentiate the corpus luteum and corpus albicans
Corpus luteum + atretic follicle = CT scar called the corpus albicans
-corpus luteum is cellular, while the corpus albicans is fibrous
What is the epithelium of the oviduct?
How does it change in (a) width and (b) foldings as you move from the infundibulum to the intramural portion
The epithelium of the oviduct is ciliated simple columnar w/ peg cells
As you move from infundibulum –> ampula –> isthmus –> intramural portion the wall gets thicker and the invaginations get fewer.
Function of the fimbriae
Fimbriae = finger-like projections off the infundibulum of the oviduct, sweeps the ovum (which is ovulated out into the peritoneal cavity) into the oviduct
What are peg cells?
The non-ciliated cells in the epithelium of the wall of the oviduct
-secrete substances to provide nutrients and protection for the ovum, and to activate the sperm
Which part of oviduct epithelium is dependent on steroid hormones?
The cilia of the simple columnar (ciliated) cells require hormones to maintain their cilia
-once estrogen is present: peg cells grow taller and cilia become much more abundant
Where does fertilization normally take place?
Near the junction of the ampulla and the isthmus (in the ampulla)
-isthmus has a very thick muscular wall w/ not well folded mucosa
Define the myometrium? What two things happen to the myometrium during pregnancy?
= middle layer of the uterine wall
Myometrium made up of three layers of interlacing muscle
-during pregnancy growth occurs via hypertrophy (cells get larger) and hyperplasia (increase in number of cells)
Differentiate the two layers of the endometrium by
- location
- function
- types of arteries present
Basalis layer- closest to the myometrium, is retained after menstruation to proliferate and renew the epithelium
-has straight arteries
Stratum functionalis is the region that is sloughed off during menstruation, is on the periphery
- contains spiral arteries
- directly responsive to hormones
List the phases of the menstrual cycle
MPS (“my professor Sally”)
- day 0-4 = menstrual phase
- day 5-14 = proliferative phase = follicular phase
- day 15-38 = secretory phase = luteal phase
Describe the proliferative phase of the mentrual cycle
- days 5-14
- follicles are developing (=> = follicular phase)
- estrogens starting to be produced
- at the beginning (day 5) only the stratum basalis is left
- cell renewal occurs to regenerate the glands and the epihtleium
- glands are straight
- minimal glycogen production
Describe the secretory phase of the mentrual cycle
- day 15-28, = luteal phase
- dependent on progesterone produced by the corpus luteum
- endometrium thickens
- progesterone stimulates production of glycoproteins (secretory product) which moves apically w/ time
- glands become highly coiled
- so basically: thick mucoid secretion w/ a lot of glycogen and coiled glands
Describe the menstrual phase of the mentrual cycle
- days 0-4
- w/o HCG (no implantation => no placenta) the corpus luteum degrades => less progesterone and estrogen around => endometrium (specifically stratum functionalis) sheds
- coiled arteries contrict (due to lack of progesterone) which causes ischemic necrosis and death of the functionalis layer
- the arteries above the constrictions rupture => blood pools in the functionalis layer
- basalis layer still receives blood from the straight arteries (=> maintained)
- in early menstrual phase: see edema of the tissue and intact epithelium
- tissue is seen sloughing off
- leukocyte infiltration may be seen
Vagina
(a) What type of epithelium
(b) Explain the vacuolated appearance of cells
(c) Explain the pH
(d) Biggest difference from cervix structurally?
Vagina
(a) non-keratinized stratified squamous
(b) Cells appear vacuolated due to accumulations of glycogen
(c) Glycogen is released and metabolized by bacteria (normal flora) creating an acidic pH that prevents the growth of pathogenic bacteria
(d) Vagina has no glands
What location does a pap smear take cells from?
Try to get cells right at the abrupt junction btwn the simple columnar epithelium of the cervix (w/ mucus glands and mucus secreting cells) and the stratified squamous of the vagina (w/o glands)
Describe the epithelium of the cervic
Mucous glands w/ simple columnar eptihelium w/ mucus secreting cells
Describe the mammary gland of a non-lactating, never pregnant female
Only the duct system is present
- tons of dense CT and fat
- no alveoli (b/c not active)
Describe the mammary gland of a non-lactating, previously pregnant female
Not currently lactating => not very active (mostly dense CT and duct system) , but since was pregnant before there are some alveoli present
Describe the mammary gland of an actively lactating woman
- lobes become distnct
- great increase in amount of alveoli and size of the glandular system
- CT and fat substantially decreased
What are septa of the mammary glands?
CT separation of lobules (clusters of alveoli)
-alveoli = the functional units
What is colostrum?
The first secretion from the mammary gland to appear after birth
- almost no lipid (b/c baby can’t break down lipids yet)
- tons of protein and lacrose
- tons of antibodies, mainly IgA for passive immunity
Describe the composition of breast milk
- milk proteins (caseins), lipids, and lactose
- antibodies: predominately IgA to provide the infant w/ passive immunity
What forms the maternal side of the placenta?
Endometrium that has thickened to form the decidua basalis
What are characteristics of the fetal side of the placenta?
The chorionic plate and large (distinctly visible) fetal vessels
-out of the chorionic plate grow tons of villus: large villi branches that can grow all the way down to the maternal decidual plate (anchoring villus) or branches w/ insanely ubiquitous branching
Describe the overall functional structure of the placenta
Chorionic vili grow out of the chorionic plate and get bathed in a pool of maternal blood released from the spiral arteries of the endometrium
Describe what happens to the cytotrophoblast and syncytiotrophoblast layers as the pregnancy progresses.
The cytotrophoblast layer is almost lost (cyto helps make more syncytio and so late in pregnancy you don’t need to be making any more).
The syncytiotrophoblast begins to thin out to allow for more efficient nutritent exchange (fetus getting bigger => increased energy requirements)
Also, blood vessesl get closer to the wall of the vilus to increase exchange
What is an easy way to distinguish maternal and fetal side of the placenta?
On the fetal side you can see the enlarged fetal bood vessels around the chorionic plate
What is a key growth factor in oogenesis?
IGF-1
Once a primordial follicle is activated, how long does it take until the follicle can be ovulated?
About an entire year!
What is the hilus of the ovary?
Where the blood vessels and nerves enter
What is the medulla of the ovary continuous with?
The mesovarium = portion of the broad ligament of the uterus that suspends the ovaries
What follicles do you find in a cross section of an average woman in her 20s?
See follicles at all stages since the process is continuous and takes about a total of one year
-majority will be primordial follicles in the cortex, but see all stages
What is the tunica albiginea?
Layer of dense CT right below the geminal epithelium in the cortex of the ovary
-oocyte has to be excreted thru this for ovulation to occur
What is the function of the glycosaminoglycans in ovulation?
Acts like glue to stick to the end of the stigma of the ovary so that the egg is suspended and precisely picked up by the oviduct
-ensures that the egg is not just free to diffuse around
Describe the structure and function of the synctiotrophoblast
Matures into vili to invade the maternal blood vessels (called lacunae) to provide nutrition for the embryo
-structure: true synctium of multi-nucleated cells
What are Hofbauer cells
Resident macrophages of the placenta
-fxn = prevent transmission of pathogens from mother to fetus
What acts as the barrier to prevent proteins and pathogens from crossing the placenta?
Syncitiotrophoblast = giant, multinucleated (true syncitium)
-there are a few exceptions: infectious agents that can cross the placenta = CMV, measles, syphilis
Describe how IgG immunoglobulins are transported across the placenta
Receptor mediated uptake into fetal circulation
-in the third trimester IgG receptors are induced in the synctiotrophoblast to allow transcytosis of antibodies
=> the fetus is equipped w/ a maternal set of IgG
What hormone stimulates the production of milk-secreting cells in the mamory gland?
Prolactin
What hormone controls the secretion of milk from the mammary glands?
When is this induced?
Oxytocin
- controls by contracting myoepithelial cells that line the acini to contract and extrude the secretory product into the duct system
- induced by baby suckling on nipple (example of neuroendocrine activity)
