212. Histology of Female Repro System

Question 1

What are the 4 layers of ovary

Answer 1

1. “Germinal epithelium” = simple cuboidal, continuous with visceral peritoneum
2. Tunica Albuginea = dense c.t. capsule
3. Cortex (w/ follicles and oocytes)
4. Medulla (loose c.t. with vessels, rete ovarii)

Question 2

What are the 4 key stages of follicle development?

What are the 6 features of the mature follicle?

Where do oocyte maturation steps occur?

What is the driving force of ovulation?

Answer 2

1. Primordial follicle: simple squamous GCs around follicles
2. Primary Follicle: GCs become stratified columnar
3. Secondary (antral) follicle: Cavity forms
4. Mature follicle: huge secondary follicle

i. Outer Theca (Theca externa - ct; Theca interna - vascular endocrine tissue producing androgens)
ii. Basal Lamina
iii. Stratum granulosum (avascular, aromatase)
iv. Zona Pellucida surrounding oocyte (role in fertilization)
v. Cumulus oophorus: follicular cells around oocyte
vi. Corona radiata: cumulus cells in contact with zona pellucida, ovulated with egg

1st meiotic division: in fetal primordial follicles (arrested in prophase) - completes just before ovulation (decades later, forming secondary oocyte)
2nd meiotic division: completed at ovulation

Ovulation: release of secondary oocyte, corona radiata, other follicular cells/fluid
- driven by proteolytic degradation of tunica albuginea and smooth muscle contraction

Question 3

Corpus Luteum

• what cells differentiate to CL cells?
• function/course of CL
• ddx atretic follicles from CL

Answer 3

GC = granulosa lutein cells
Theca interna cells = theca lutein cells (produce P)

CL: maintained by LH from ant pit

• produce P = inhibits LH eventually
• no pregnancy: CL degenerates into corpus albicans (white body) and disappears
• pregnancy: hCG maintains CL for pregnancy

Atretic follicles: smaller wavier, less folded, more numerous than corpus albicans

Question 4

What are the 4 parts of the uterine tube starting from the uterus?

What is the arterial supply of the ovary, vagina, uterus, fallopian tube?

What are the 4 layers of the fallopian tube? How do they change with ovulation?

Answer 4

Intramural segment > Isthmus (narrowest) > ampulla > infundibulum (with fimbriae)

Uterine A = ovary, vagina, uterus (through mesovarium)
Ovarian A = ovary and fallopian tube

1. Serosa (visceral peritoneum)
2. Muscularis
3. Mucosa (with complex folds) = c.t.
4. Simple columnar epithelium
   - ciliated cells: increase in number in response to E (help move ovulated egg)
   - non-ciliated (peg) cells: produce fluid with glycogen to nourish egg/sperm/migration (more in mp)

Question 5

What are the 3 layers of uterus?

What are the 2 layers of the inner layer? How does this layer change during menstruation (menstrual phase, proliferative phase, secretory phase)?

Answer 5

1. Serosa (visceral peritoneum)
2. Muscularis (myometrium = hypertrophies only in pregnancy)
3. Mucosa (endometrium, decidua)

Endometrium

i. Stratum Functionale: simple columnar epithelium, tubular uterine glands, lost in menstruation
ii. Stratum Basale: maintained in menses, engaged with myometrium, spiral arteries (ascent to s.f., constrict in low E/P promote shedding), straight artery (from radial branch of myometrium - uterine artery) local to stratum basale

Menstrual Phase: No stratum functionale (VC low E/P), no epithelium, basal glands prominent/bent/circular (source of epithelial regeneration)

Proliferative Phase: during follicle development, stratum functionale rebuilds, few straight glands visible

Secretory Phase: after ovulation, CL makes P/E, stratum functionale filled with WAVY glands (dilated with glycogen-rich fluid), thickest endometrium (6mm)

Question 6

What are 4 key differences in cervix histo compared to uterus?

Vagina: type of epithelium, glands, lubrication, change with menses

Answer 6

Cervix: 1. muscularis is 50% c.t. (more structural, does not expand in pregnancy), 2. mucosa changes little with menstruation, 3. more branched glands, 4. normal cysts form (plugged gland dilations), 5. transition zone: epithelium changes from simple cuboidal to stratified squamous

Vagina

• stratified squamous epithelium (non-keratinized)
• no glands (spaces are vascular channels)
• lubrication: from cervix and greater vestibular gland (below vagina)
• epithelial cells swell with glycogen in high E (fixed cells look empty, glycogen nourishes sperm, bacteria feast on glycogen and lower pH to 4 to protect from worse invasion)

Question 7

How do mammary ducts change during menstrual follicular phase and luteal phase?

Answer 7

follicular phase: increased mammary duct formation

luteal phase: increased secretory end pieces of mammary gland epithelium, dilation with milk