RT Book, Section
A1 Bhagavath, Bala
A1 Conway, Gerard S.
A1 Carr, Bruce R.
A2 Sarafoglou, Kyriakie
A2 Hoffmann, Georg F.
A2 Roth, Karl S.
SR Print(0)
ID 1140321044
T1 Female Hypogonadism
T2 Pediatric Endocrinology and Inborn Errors of Metabolism, 2e
YR 2017
FD 2017
PB McGraw-Hill Education
PP New York, NY
SN 9780071773140
LK accesspediatrics.mhmedical.com/content.aspx?aid=1140321044
RD 2024/04/19
AB Between  weeks  4  and  8  of  gestation,  undifferentiated  germ  cells  migrate  from  the  yolk  sac  to  the  genital  ridges  where  they  populate  and  allow  the  development  of  the  ovaries  by  differentiating  into  oogonia.  By  week  6  of  gestation  mitosis  of  the  oogonia  begins,  resulting  in  a  population  of  over  3  million  germ  cells  per  ovary  by  20  weeks.1  From  15  weeks,  the  oogonia  begin  to  transform  into  oocytes  by  entering  the  first  meiotic  division  which  stops  at  prophase  I.  No  further  development  occurs  until  menarche,  when  the  first  few  go  forward  to  complete  meiosis  I  and  proceed  toward  ovulation  as  a  secondary  oocyte.  Meiosis  II  immediately  follows  meiosis  I  but  is  arrested  at  metaphase  II  and  is  only  completed  if  fertilization  occurs.  Primordial  follicles  are  formed  from  about  20  weeks  gestation  as  granulosa  cells  move  to  surround  each  germ  cell.