Embryogenesis

Question 1

What is a primordial germ cell

Answer 1

*Germ cells are “totipotent”
* They can give rise to any type of somatic cell
* They also give rise to daughter cells that remain “germ
line” and are themselves totipotent

Question 2

Primordial germ cells originate close to _______ and can be identified there by end of how many weeks?

Answer 2

extraembryonic endoderm of yolk sac
3rd week gestation

Question 3

Primordial germ cells migrate to the developing gonad under the influence of ____ genes. Precursor must express ____ (downstream mediators of previous genes)

Answer 3

BMP-2, BMP-4,and BMP-8B (and many other genes)
SMAD1, SMAD5, and SMAD8

Question 4

Primordial germ cells reach the genital ridge by ___ weeks gestation

Answer 4

6

Question 5

In female, stem cells that reach genital ridge are called

Answer 5

oogonia

Question 6

at 8 weeks gestation ~ ___ oogonia, with proliferation/peak levels (under exposure to retinoid acid) at ___ weeks (6-7 million). They will go through meiosis and develop into primary oocyte or undergo atresia. By birth likely no oogonia left.

Answer 6

600,000 oogonia
20 weeks

Question 7

Primary oocyte is stuck in what phase of meiosis

Answer 7

Prophase I (2n, 4c) chromosomal chromosomal component

Question 8

At puberty, LH surge reinitiates Meiosis (metaphase - Anaphase - Telophase - extrude polar body), and primary oocyte becomes ___ oocyte and enters meiosis II

Answer 8

secondary

Question 9

Secondary oocyte arrest at what stage of meiosis II until fertilization

Answer 9

Metaphase

Question 10

What happens to the oocyte on fertilization?

Answer 10

oocyte progresses through Meiosis II (Anaphase - telophase) and extrudes the second polar body to complete Meiosis II

Question 11

GV oocyte is in what phase of division

Answer 11

Prophase 1

Question 12

Features of GV oocyte morphology

Answer 12

Immature
compact corona with few cumulus cells
prominent GV and nucleolus
4c, 2n

Question 13

Features of MI oocyte morphology

Answer 13

No polar body
dense cumulus cells
GV and nucleolus have faded
4c, 2n

Question 14

GV oocyte breakdown signals resumption of

Answer 14

Meiosis I

Question 15

Features of MII oocyte morphology

Answer 15

Extruded polar bosy
cumulus cells expanded and lutinized
corona radiata “ sunburst pattern”
2c, 1n

Question 16

Folliculogenesis: Primordial follicles are made up of a single layer of

Answer 16

squamous like granulosa cells

Question 17

Folliculogenesis: Primary follicles are made up of a single layer of

Answer 17

cuboidal granulosa cells

Question 18

Folliculogenesis: Secondary follicles are made up of multiple layers of ___ and some ___ cells

Answer 18

granulosa cells theca cells (beginning of development)

Question 19

Folliculogenesis: Antral follicles are identified by accumulation of ___

Answer 19

follicular fluid, estrogen dominates the production of this follicle

Question 20

Folliculogenesis: Periovulatory follicle are notable for presence of ___ receptors?
___ induces proteolysis of follicle wall by inducing plasminogen activators+collagenase+prostoglandins (PGE, PGF)
___ expands the cumulus

Answer 20

Progesterone
LH
Hyaluronic acid

Question 21

___ keeps primirdial follicles form developing

Answer 21

AMH

Question 22

AMH is made by what stages/types if follicles

Answer 22

primary and secondary follciles