Week 1: Ovaries and Fallopian tubes micro anatomy

Question 1

General structure of ovary

Answer 1

1. epithelium: simple cuboidal epithelium
2. tunica albuginea: DCT layer between epithelium and cortex
3. Cortex: contains follicles
4. Medulla: blood vessels in LCT
5. Hilum

Question 2

Folliculogenesis: primordial and primary follicle

Answer 2

1. Primordial follicle: can sit for a long time. single layer of granulosa cell
2. primary follicle: granulosa cells go from squamous to cuiboidal and undergoes hyperplasia, stimulated by FSH and estrogen from the developing follicle. Oocyte enlarges. Formation of zone pellucida (glycoprotein coat around oocyte)-prevent polyspermy, protect early embryo. Thecal layer.

Question 3

Oogenesis

Answer 3

• before birth: oogonium undergoes mitotic proliferation to make primary oocytes (46 2n/4c)
• after puberty, primary oocyte: One undergoes first meiotic division before ovulation -> forms a polar body and a secondary oocyte (23 haploid 1n,2c)
• undergoes second meiotic division after fertilization to become mature ovum (23 haploid 1n,1c +23 haploid from sperm)

Question 4

Follicular atresia

Answer 4

• fate of most oocytes
• can happen at any stage of follicular development
• part that remains the longest is zona pellucida

Question 5

follliculogenesis: antral and mature follicle

Answer 5

3. Antral follicle: formation of fluid filled cavity. Estrogen binding protein within, sequesters high estrogen content.
   - mural granulosa cells -along wall of follicle
   - thecal cells have fat droplets inside
4. Mature (Graaffian) follicle:
   - increase in size
   - oocyte surrounded by cumulus oophorus (granulosa cells and hyaluronic acid).
   - Inner most cumulus, are corona radiate.
   - cumulus cells go with oocyte at ovulation.
   - mural granulosa cells: stay behind to form CL.

Question 6

Luteal phase-microanatomy

Answer 6

• large and small luteal cells from granulosa and thecal cells respectively
• massive ingrowth of blood vessels
• corpus albicans- remnant of CL, made of collagen mainly

Question 7

Structure of fallopian tube

Answer 7

• egg moves towards uterus by cilia, sperm move toward ovary by fluid flow
  1. Utero-tubal junction: fewest mucosal folds. filter to screen out abnormal spermatozoa.
  2. Isthmus: narrow segment; site for sperm storage
  3. Ampulla: wide middle segment. Extensive branched mucosal folds. Common site of fertilization
  4. infundibulum: distal segement
• fimbriae: fingerlike extensions of mucosal folds, to help catch oocyte from ovary

Question 8

Histology of fallopian tube

Answer 8

• mucosa: simple columnar epithelium with cilia and mucus secreting peg cells
• Muscularis: smooth muscle layers, inner circular, outer longitudinal