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Oogenesis

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Oogenesis Production of Ova What is Oogenesis The formation, development, and maturation of an ovum. Oogenesis begins in the female embryo Primoridal germ cells ... – PowerPoint PPT presentation

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Title: Oogenesis


1
Oogenesis
  • Production of Ova

2
What is Oogenesis
  • The formation, development, and maturation of an
    ovum.

3
Oogenesis begins in the female embryo
  • Primoridal germ cells differentiate into oogoina
    (stem cells)
  • At 2 7 months of gestation, 1000 oogonia
    divide to form 7 million germ cells

4
The meiotic resting phase is called the dictyotene
  • From 7 9 months, most oogonia die
  • the remaining enter the first meiotic division
  • primary oocyte
  •  The primary oocytes remain resting within small
    follicles until puberty

5
Ovary
6
Process of Ovulation
  • Started by drop in estrogen
  • Signals hypothalamus to release GnRH
  • GnRH goes to pituitary, and it relases FSH
  • Increase in FSH stimulates about 20 oocytes to
    mature
  • Meiosis I to form secondary oocyte
  • One oocyte (in most cases) matures and is
    expelled. The others are reabsorbed before
    ovulation occurs

7
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8
Follicle
  • Estrogen and progesterone are secreted by some of
    the cells in the follicle
  • Cytoplasm and nutrients
  • Ovulation occurs when follicle and ovarian
    surface open

9
Corpus leuteum
  • The empty follicle becomes the corpus leuteum
  • If pregnancy does not occur, it is reabsorbed
  • If pregnancy does occur, it produces hormones
    that help maintain pregnancy

10
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