Oogenesis

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Oogenesis

• Production of Ova

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What is Oogenesis

• The formation, development, and maturation of an
  ovum.

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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

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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

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Ovary
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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

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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

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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

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