Female Reproductive Histology Flashcards
how does the histology of the ovaries change throughout the reproductive years?
Before puberty, ovaries have a smooth surface
Throughout the reproductive years, the ovaries becomes scarred and irregular due to repeated ovulations
In post-menopause, the ovaries are a fourth of their original size
when during embryogenesis do the germ cells migrate from the yolk sac to the gonads?
week 4
female primordial germ cells
oogonia - migrate to the ovarian cortex during embryonic week 4 and undergo mitotic proliferation by the 5th month of gestation
the ______ ligament contains the ovarian vessels
suspensory ovarian ligament
what is found in the cortex vs medulla of the ovary?
cortex: follicles (various stages of development, mostly primordial) + stroma (vascular and cellular)
medulla: loose CT, vessels, nerves
how do primordial follicles appear histologically?
primary oocyte - large cell in prophase of meiosis I, euchromatic nucleus with prominent nucleolus
follicular/granulosa cells - single layer of flat cells surrounding oocyte
how do primary follicles appear histologically? name the included structures (6)
from inside to outside:
1. primary oocyte
2. zona pellucida (glycoprotein, made by oocyte) - bright circle
3. follicular/granulosa cells - cuboidal, connected to oocyte via cell processes and gap junctions
4. basement membrane
5. stromal theca cells interna - steroid-producing with lipid droplets
6. stromal theca cells externa - connective tissue, no endocrine function
how does a secondary/ Antral follicle appear histologically?
from inside to outside:
1. primary oocyte
2. zona pellucida - bright ring
3. follicular/granulosa cells (6-12 layers)
4. antrum - fluid-filled cavity with hormones from glomerulosa cells
5. basement membrane
6. theca interna - LH-induced secretion of androstenedione
7. theca externa - blends with stroma
how do mature/Graafian follicles appear historically?
from inside to outside:
1. secondary oocyte (if this oocyte is undergoing ovulation)
2. zona pellucida
3. granulosa cells forming cumulus oophorus (“hill”) and corona radiata (“crown”)
4. very large antral cavity
5. basement membrane
6. theca interna
7. theca externa
what changes occur to a mature/Graafian follicle if the follicle undergoes ovulation?
the primary oocyte continues meiosis up to metaphase II to become a secondary oocyte + polar body
the oocyte and corona radiata are released
meiosis II is completed if fertilization occurs
what are the distinctive histological features of primordial, primary, secondary/Antral, and mature/Graafian ovarian follicles?
primordial - single layer of flattened follicular/granulosa cells
primary - 1+ layers of cuboidal follicular cells and zona pellucida appears
secondary/Antral - antral cavity appears
mature/Graafian - largest follicle with very large antral cavity
how can atretic follicles (degenerating) be identified histologically?
thick, folded basement membrane/ zona pellucida + invading macrophages
what is an ovarian stigma?
stigma aka macula pellucida: area of the ovarian surface (tunica albuginea) where the Graafian follicle bursts through during ovulation and releases the ovum
proteases from fibroblast degrade connective tissue
fill in the blanks regarding the development of the ovarian corpora (“bodies”) during the luteal phase: ovulated graafian (mature) follicle —> ________ —> __________ —> _________
ovulated graafian (mature) follicle —> corpus hemorrhagicum (“bleeding body”) —> corpus luteum (“yellow body”) —> corpus albicans (“white body’)
how do granulosa vs theca cells appear histologically in the corpus luteum?
granulosa - increase in size to become large/round/pale, centrally located, majority of corpus luteum
theca - smaller and darker, peripherally located in folds
“white body” scar that forms after the corpus luteum has degenerated
corpus albicans - due to lack of LH stimulation, fibroblasts produce scar of dense connective tissue (not very cellular)
what are the regions of the fallopian tubes?
infundibulum - opens into peritoneal cavity, fimbriae around ovary, receives ovulated egg
ampulla - region of fertilization or ectopic pregnancy
isthmus - narrowed portion
intramural - opens into uterus
what are the tissue layers of the uterine tube, ampulla, and infundibulum? (3)
- mucosal folds: simple ciliated columnar + non-ciliated peg cells (nourish egg/embryo)
- muscularis: 2 layers of smooth muscle for peristalsis
- serosa: visceral peritoneum
what are the histological layers of the uterus?
- endometrium: simple columnar mucosa with tubular glands + lamina propria
- myometrium: 3 layers of smooth muscle, site of lyomeioma fibroids
- perimetrium: serosa/parietal peritoneum
how do the stratum functionalis vs stratum basalis of the uterine endometrium differ histologically?
stratum functionalis: thick, superficial, contains spiral arteries, changes throughout menstrual cycle
stratum basalis: thin, deep, contains straight arteries, glands/CT regenerate functionalis layer
how does the histology of the stratum functionalis layer of the uterine endometrium change throughout the menstrual cycle?
menstrual phase - degeneration of corpus luteum results in shedding
proliferative phase - underlying stratum basalis proliferates to regenerate the stratum functionalis with straight/narrow tubular glands
secretory phase - thick with saw-toothed/ convoluted secretory glands
how does the decidual reaction change the histology of the endometrium following implantation?
endometrium becomes thicker + more vascular and glands become more active
stromal cells enlarge and fill with glycogen/lipids —> become decidual cells of pregnancy, contributing to the maternal part of the placenta
how does mifeprostone/RU486 work
abortion pill that binds progesterone receptors in the endometrium, causing necrosis and detachment of the embryo/fetus (<10 weeks gestation)
how does misoprostol work?
abortion pill, synthetic prostaglandin that binds to myometrial cells and causes strong contractions which lead to expulsion of the detached conceptus
what cyclic changes occur in the uterine cervix during ovulation vs the luteal phase?
mucus is thin and basic at ovulation for sperm entry
mucus is thick and acidic in luteal phase for protection
what type of epithelial tissue is found in the uterine cervix? (hint, there are regions)
endocervix: simple columnar, mucus-secreting, appears as crypts
squamo-columnar junction: columnar and squamous epithelium meet
ectocervix: non-keratinized stratified squamous
vagina: stratified squamous epithelia containing glycogen
why do Nabothian cysts occur?
increased estrogen during the menstrual cycle induces squamous metaplasia of the columnar epithelium
Nabothian cysts in the uterine cervix form when the squamous metaplasia covers the mucus-secreting columnar cells and traps the secretions
where do most cervical cancers caused by HPV (human papilloma virus) originate and why does this make sense?
majority originate in the transformation zone of the uterine cervix, where columnar epithelium undergoes squamous metaplasia (induced by estrogen during the menstrual cycle)
replication/differentiation during squamous metaplasia may be favorable for HPV replication
which 2 strains of HPV (human papilloma virus) cause most cervical cancers (~70%)?
HPV-16 and HPV-18
what are the 3 histological layers of the vagina?
- mucosa: non-keratinized squamous, NO glands (mucus comes from cervix) + lamina propria rich in elastic/venous plexus/leukocytes
- muscularis
- adventitia
how is a low pH maintained in the vagina?
normal bacterial flora (Lactobacillus acidophilus) metabolizes glycogen in squamous cells to produce lactic acid
where are Peg cells found in the female reproductive tract?
oviduct, along with ciliated cells that push the oocyte along
site for implantation and ectopic pregnancy
where is Wharton’s jelly found in the female reproductive tract?
Wharton’s jelly: mucous-like embryonic connective tissue found in the umbilical cord
what is the maternal vs fetal portion of the placenta and from what are they derived, respectively?
chorion: fetal part of the placenta derived from trophoblast (OCM), differentiates into cytotrophoblast (inner) and syncytiotrophoblast (outer), drives implantation/vascular invasion of endometrium, secretes hCG/hPL
decidua: maternal part of the placenta formed from transformation of the endometrium (decidual reaction)
where can you find Hofbauer macrophages?
placental macrophages (role unknown)
lactiferous duct vs lactiferous sinus vs alveoli (of the mammary glands)
lactiferous duct: where each lobe drains to the nipple surface
lactiferous sinus: dilations for milk storage near the nipple, lined by cuboidal-columnar and myoepithelium
alveoli: secretory unit, lined by cuboidal and myoepithelium
how does the histology of the mammary glands change when they are inactive vs active vs lactating?
inactive: a lot of connective tissue (dense CT separates lobes, loose CT surrounds secretory units)
active: secretory units (alveoli) present, little connective tissue
lactating: secretory units with colostrum-milk, very little connective tissue
