Female histo

Question 1

Ovary histology

Answer 1

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

Question 2

Non-cyclical follicular development

Answer 2

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

Question 3

Primordial follicle structure

Answer 3

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

Question 4

Non-cyclical primary follicle structure

Answer 4

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

Question 5

Primary follicle (multi-laminar) structure

Answer 5

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

Question 6

Zona reaction

Answer 6

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

Question 7

Secondary follicle structure

Answer 7

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

Question 8

Graafian/Antral follicle structure

Answer 8

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

Question 9

Corpus luteum - fertilized ovum

Answer 9

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

Question 10

Corpus luteum - no fertilization

Answer 10

short lived

corpus albicans

Question 11

Myometrium overview

Answer 11

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

Question 12

Uterine walls

Answer 12

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

Question 13

Endometrium

Answer 13

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

Question 14

Endometrial layers

Answer 14

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

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

Question 15

Menstrual phase endometrium

Answer 15

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

Question 16

Proliferative phase endometrium

Answer 16

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

Question 17

Arteries of the uterus

Answer 17

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

Question 18

Radial arteries of the uterus

Answer 18

Straight: supplies basal layer
Spiral: supplies functional layer

Question 19

Glands of the uterus during proliferative phase

Answer 19

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

Question 20

Secretory phase uterus

Answer 20

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

Question 21

Glandular changes during secretory phase

Answer 21

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

Question 22

Implantation histology

Answer 22

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

Question 23

Trophoblast differentiation

Answer 23

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

Question 24

Development of the placenta

Answer 24

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

Question 25

Placenta histology >5 mo

Answer 25

fetal/maternal interface: maternal blood in the lacunae

fetal blood in fetal vessels in the villi

Question 26

Diffusion barrier between fetus and mother

Answer 26

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

Question 27

Histology/dating of the placenta

Answer 27

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

Question 28

Histology/dating of the placenta >5 mo

Answer 28

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

Question 29

Histology/dating of the placenta toward term

Answer 29

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

Question 30

Fertilization timing

Answer 30

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

Question 31

Fertilization place

Answer 31

usually at the ampulla of the Fallopian tube

Question 32

Process of fertilization

Answer 32

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