W9- Lecture 46- Origin and Development of germ cells

Question 1

when does the germ cell move from the epiblast to the yolk sac ?

Answer 1

3 weeks post coitus

Question 2

where does migration of the primordial germ cells happen in the 24day pc

Answer 2

from yolk sac, through hind-gut to genital ridge

Question 3

what happens with sex chords in male and female development ?
what does this lead to

Answer 3

females they degenerate
male that stay as structure
in men the germ cells are in the seminiferous tubules with pro-Sertoli cells

Question 4

what do pro-Sertoli cells develop via mitosis form ?

Answer 4

gonocytes

Question 5

what do gonocytes cells develop via mitosis form ?

Answer 5

Gonocytes proliferate by mitosis and develop into Pro-spermatogonia.

Question 6

what do Pro-spermatogonia cells develop via mitosis form ?

Answer 6

These develop into Spermatogonia by the end of the foetal stage.
total

Question 7

describe the embryonic development of sperm cells

Answer 7

spermatogonium +pro-Sertoli to gential ridge
pro-Sertoli to Gonocytes
Gonocytes to Pro-spermatogonia
Pro-spermatogonia to spermatogonia

Question 8

in the Prepubertal phase what happens to the Earliest spermatogonia ?

Answer 8

become stem cells and acquire self-renewal capacity

Question 9

describe the difference between spermatogonia proliferation in rodents and humans
+ benefits of each

Answer 9

Rodents: A0 considered to be stem cells. Give rise to a succession of generations of A s’gonia (Apaired, Aaligned, A1-4) goes to Intermediate goes to B

Allows dramatic expansion of a small stem cell pool.

Primates (incl. humans): Adark considered to be stem cells. Apale are proliferative goes to Intermediate goes to B.

Large reserve of stem cells & relatively few proliferative divisions.
- can be applied in treatment

Question 10

Peri-natal spermatogonial division produce what cell ?

Answer 10

spermatocytes

Question 11

in what stage of the cell cycle do Spermatocytes arrest in ?

when do they exit this

Answer 11

Spermatocytes arrest in prophase of 1st meiotic division

at puberty

Question 12

spermatogonia give rise to ?
1 to 2 to 3
+ role ()

Answer 12

Preleptotene spermatocytes(S-phase )
Leptotene(chromatin remodelling )
Zygotene (chromatin remodelling )
Pachytene s'cytes	(transcription, translation)
Diplotene s'cytes	(enter meiosis)
goes to 
1st meiotic division
goes to 
2nd meiotic division 

Secondary s’cytes (NB: haploid –homologous chromatids have separated)