Sept4 M1-Histology_Female_RS Flashcards
menarche def
- first menstrual flow at 13 years approx
- cyclicity of 28 days starts
- stops at menopause at 51
parts of the ovary (histo)
- germinal epith (surrounding ovary) (cuboidal simple epith)
- tunica albuginia under the germinal epith (thick layer of CT)
- cortex (follicles. lot of small ones on periphery, granular appearace)
- medulla (part close to hilus) (rich in loose CT, large pop of vessels)
- corpora atretica (scars from follicles replaced by CT)
- developing follicle(s)
- corpus luteum
- hilus (like a hilum)
- blood vessels (near hilus)
follicles develop where in the ovary
cortex
steps of primordial follicles formation
- primordial germ cells (derived from yolk sac which is separated from the fetus) travel and wander until reach the UG ridge. There, transform into oogonias (divide a lot.) 600 000 at 2 months, 700 000 at 5 months). eventually reach ovary when done travelling
- between month 3 and 7 of embryo, most oogonia begin to enter prophase 1 (occytes) but stop at the diplotene stage (step 4 of prophase 1) (sister chromatids together, homologs separated, actively transcribing)
- birth = 150000-400000 oocytes total (both ovaries). only 500 will mature
when is the first meiotic division of a primordial follicle COMPLETED
when it completes all steps for ovulation and is ovulated**
what is found under the tunica albuginia in the cortex
large pop of follicles including primordial follicles
primordial follicles charact
- smallest ones
- surround by flat follicular cells
- contain an oogonia
step after primordial follicles
primary follicles (unilaminar) (transformation from primordial to primary only starts at puberty**)
- contain a primary oocyte
- surrounded by ONE layer of cuboidal epith of follicular cells called granulosa cells
- GCs rest on BM outside of the cuboidal epith
ovulation def in terms of meiosis
completion of first meiotic division
when primordial to primary unilaminar transformation occurs and why
- at puberty (age 13 approx)
- is dependent on FSH
step after primary follicle unilaminar
primary follicle multilaminar regulated by FSH
- GCs divide forming many layers
- last layer resting on BM (so epith cells)
what happens in primary follicle multilaminar regulated by FSH after the many layers of GCs formed
- GCs close to oocyte start to make an EC material called zona pellucida (with small contribution from oocyte)
- around the follicle (out of BM), stromal fibroblast-like cells differentiate into a theca
step after the developed primary multilaminar follicle
secondary (antral follicle)
- GCs make a liquor folliculi, forming cavity called antrum
- antrum enlarges with time
stage of meiotic div of oocyte in secondary antral follicle
prophase 1 diplotene
what happens in secondary antral follicle after antrum formed
theca cells diff into theca interna and externa that is vascularized and very rich in capillaries
what does theca interna of secondary antral follicle do
theca interna cells have a big SER and make androstenedione
what does the theca externa of secondary antral follicle do
is just a layer of fibrocytes appearing darker than the interna
appearance of theca interna of secondary antral follicle on histo
H and E on LM = spaces in theca bc. The lipids (steroids) of the SER are not staining well, typical of steroid producing
what happens to androstenedione produced by theca interna cells in the secondary antral follicle
GCs use aromatase enzyme to transform androstenedione into estradiol
what happens in the developing secondary antral follicle
- antrum becomes larger (more follicular fluid made)
- fluid invades GCs
- GCs divide into group close to oocyte (cumulus oophorus)
name of layer of GCs of the cumulus oophorus that is closest to the oocyte and its function
corona radiata. is the GCs that where making the ZP. now being called the corona radiata
what happens to the oocyte through the diff steps: primordial, primary uni and multilaminar and secondary (antral) follicles
gets bigger because it accumulates cytoplasmic components
step after secondary (antral) follicles
of all the secondary antral follicles, one will develop into a mature, Graafian follicle
-the antral fluid goes in the back of the oocyte (still stuck to GCs) and the corona radiata (with the oocyte in its middle) will be released in the lumen of the antrum and float there.
steps of ovulation
- LH surge causes release of PGs + histamine + powerful enzyme collagenase
- collagenase dissolves stuff where Graafian follicle is (dissolves the tunica albugenia at the level of the stigma. stigma = where Graafian follicle bursts out)
- the germinal epith underneath the Graafian follicle separates
- oocyte + corona radiata floating in antrum are released and captured by the fimbriae
- local edema
- released oocyte completes 1st meiotic division
fimbriae histo
fingers projecting to ovaries. mucosa associated SM cells
FSH function in menstrual stage (as increases)
recruits a number of multilaminar primary follicles
- get bigger
- reach antral secondary stage
- one becomes dominant
- the rest can stay for next menstrual cycle or become atretic
signs of follicle degeneration on histo
- GCs dying
- ZP disappearing
- no nucleus in oocyte
- when die, all replaced by CT
follicular atresia (corpus lutea atretica) early stage
- see antrum + ZP
- most GCs dying
- CT invades
- capillaries and the scar form
follicular atresia (corpus lutea atretica) advanced stage
- oocyte gone
- ZP gone
what happens to the Graafian follicle when the oocyte + coronata radiata leave it (ovulation)
- collapses into a corrivated structure (corpus luteum)
- small theca cells are drawn in ridges of the big GCs, forming folds.
- blood vessels from the periphery (from the highly vascularized theca interna) enter the folds, ridges with the theca cells
- GCs become granulosa lutein cells making E and P
- theca interna cells form theca lutein cells also making E and P
- a blood clot forms during bleeding
GLCs vs TLCs (corpus luteum)
GLCs = large, less acidophilic, paler TLCs = small, more acidophilic, lot of blood vessels with them (caps)