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Flashcards in Female histo Deck (32):
1

Ovary histology

Surface epithelium - often missing from slides
Cortex: follicles are functional units
Medulla: boundary between cortices - indistinct

2

Non-cyclical follicular development

6th week embryonic: primordial germ cells (oogonia) migrate from yolk sac to gonadal primordia (presumptive ovarian cortex ) - mitosis
4/5 mo: > 7 million
Encapsulation by pre-granulosa cells and this arrest cell in first meiotid division. No oogonia in newborn.
Called primary oocytes in primordial follicles.

Primordial follicle recruitment into primary follicles start in fetal life and continues post-natally until ovarian reserve depleted
Gonadotropin INdependent

3

Primordial follicle structure

Very simple structures
cytoplasm/organelles
active nucleus with nucleolus
flattened follicular cells
surrounded by stromal cells

4

Non-cyclical primary follicle structure

still very simple structure
but cells surrounding oocyte are now cuboidal = granulosa cells
also: basal lamina separates granulosa cells and oocyte from stroma avsculature - developing follicles are avascular

5

Primary follicle (multi-laminar) structure

Granulosa cells have stratified = zona granulosum, 1st sign of follicular recruitment
Eosinophilic density forming around oocyte = zona pellucida
Granulosa cells send processes through zona pellucida to oocyte cytoplasm - gap junctions
follicle metabolically and electrically coupled
Theca folliculi on the outside of granulosa cells - interna/externa

6

Zona reaction

1) acrosomal reaction
2) rapid depolarization of oolemma
3) cortical granules fuse with oolemma
4) proteases in granules cross-link proteins in Z pellucia --> block further entry of sperm

7

Secondary follicle structure

1st sign of fluid-filled cavity = antrum
antral fluid has key role in follicular growht, oocyte maturation and ovulation
Formation poorl understood
but establizhes polarity and important regions of Graafian follicle

8

Graafian/Antral follicle structure

Zona granulosa on the periphery
theca interna present
cumulus oophorus
Corona radiata and 10 oocyte
theca externa = smooth muscle
Follicle bulging under ovarian surface

9

Corpus luteum - fertilized ovum

corpus luteum of pregnancy
same organization, but enlarged
embryo - hCG-CL continues estrogen and progesterone secretion to maintain uterine wall
taken over by placenta at 8-12 wks

10

Corpus luteum - no fertilization

short lived
corpus albicans

11

Myometrium overview

outer muscular wall of uterus
thick sm wall
undergoes changes during pregnancy for fetus protection, expulsion
- increased E during pregnancy --> hyperplasia and hypertrophy of cells/increase in uterine collagen content
3 poorly defined layers

12

Uterine walls

myometrium
endometrium
outer serosa/adventitia depending on which part of uterus

13

Endometrium

mucous membrane comprising inner layer of uterine wall
Simple columnar epithelium and lamina propria, uterine glands, arteries
Mucosal lining that undergoes significant cyclical changes

14

Endometrial layers

Basal: adjacent to myometrium
closed tips of glands
largely unchanged throughout cycle

Functional: remainder of glands/epithelium
undergoes profound changes throughout monthly cycle

15

Menstrual phase endometrium

Only the base of glands remain
no epithelium - sloughed off
Straight arteries
Entire functional layer gone, only basal layer remains

16

Proliferative phase endometrium

Day 5-6: simple columnar epithelium regenerates
Remains unchanged until once again sloughed @ menstruation
Most endometrial CA are carcinomas, arising from epithelium that lines endometrium and forms the glands

17

Arteries of the uterus

Uterine artery --> 10 arcuate arteries --> radial arteries (penetrate myometrium)

18

Radial arteries of the uterus

Straight: supplies basal layer
Spiral: supplies functional layer

19

Glands of the uterus during proliferative phase

Early proliferative: at first sparse/straight
become coiled more closely packed during late proliferative phase
Glycogen synthesis begins (nutrition for fertilized ovum)

20

Secretory phase uterus

increased progesterone induces secretory changes in epithelium
still some ongoing proliferation due to estrogen
Arteries become increasingly tortuous
spiral in and out of section

21

Glandular changes during secretory phase

No change in epithelium
Saw tooth appearance in late secretory phase
Day 16: Basal vacuolation
Later: apical vacuolation

22

Implantation histology

hatched blastocyst "sticks" to endometrial epithelium - usually at embryonic pole
trophoblast quickly starts to proliferate/differentiates into 2 layers

23

Trophoblast differentiation

Syncytiotrophoblast - outer layer
- multi-nucleated protoplasmic mass without cell boundaries
- highly invasive: produces enzymes that erode maternal tissue

Cytotrophoblast - inner layer
important in chorionic villi growht during development of placenta

24

Development of the placenta

Cytotrophoblast proliferates to form primary chorionic villi = future fetal blood vessels

Syncytiotrophoblast breaks through maternal vessels - lacunae / vessels have direct contact

Intimate diffusion barrier but no mixing of blood

25

Placenta histology >5 mo

fetal/maternal interface: maternal blood in the lacunae
fetal blood in fetal vessels in the villi

26

Diffusion barrier between fetus and mother

Fetal blood
Fetal endothelium
Connective tissue (mesenchyme core)
Syncytiotrophoblast
Maternal blood (space = lacunae)

27

Histology/dating of the placenta

Trophoblast has 2 layers: cytotrophoblast/syncytiotrophoblast (formed from underlying cytotrophoblast)
1st part of pregnancy: 2 layers usually distinct on microscopic exam - date placenta/pregnancy

Fetal vessels with nucleated fetal RBCs appear at 21 d gestation
- presence of both trophoblast cell layers in absence of vessels --> pregnancy pregnancy 21 d - 5 mo

28

Histology/dating of the placenta >5 mo

After 5 mo: cytotrophoblast when viewed under a light microscope appears to degenerate

although cytotrophoblast has become thinner, remains throughout pregnancy, and all syncytial cells formed during latter half of pregnancy are formed from cytotrophoglast
Apparent absence of cytotrophoblast signifies a pregnancy > 5 mo

29

Histology/dating of the placenta toward term

Mesenchymal core of each villus becomes more dense and compact
fetal vessels appear to be much closer to overlying syncytiotrophoblast, possible facilitating transfer of nutrients or waste products
fibrin deposition within intervillous space and occasional syncytial knots

30

Fertilization timing

ovum has to be fertilized within 24-48 h
sperm appears in outer third of fallopian tube 5-10 min after coitus, continue to travel up for about 24-48 h

31

Fertilization place

usually at the ampulla of the Fallopian tube

32

Process of fertilization

1) sperm penetrates corona radiata with acrosomal enzymes
2) Bind and penetrate zona pellucida --> acrosomal reaction etc
3) once sperm penetrates ovum, ovum completes 2nd meiotic division
4) male + female pronuclei swell and form complete set of 46 chromosomes
5) 3-5 days post-fertilization for zygote to reach uterus while undergoing cell division
6) enters uterus as blastocyst; 1-3 days later, implants