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Oogenesis

Oogenesis is defined as the creation of an ovum or egg cell. It is the female process of the male process of gametogenesis.  This process often occurs in the ovarian follicle.

During the female menstrual cycle, 10-20 follicles begin to develop due to the presence of elevated FSH. Secondary follicles turn into a single healthy secondary follicle – often by day 9 of the cycle.

The remaining secondary follicles have undergone “ovarian follicle atresia”. The only secondary follicle is now termed primary follicle. A large amount of estradiol is produced. Around day 14 of the cycle, there is an increase in LH. The polar body is formed.

1.)  The beginning step is referred to as Oocytogenesis

–  This is a transition step prior to birth
–  This is the development of oocytes

2.)  The next step is Ootidogenesis

–  Oocytes turn to ootid
–  Controlled by meiosis
–  It continues up until prophase I

Meiosis I

–  Is a division of the number of chromosomes
–  The number is cut in half
–  Is essential for sexual reproduction

Steps of Meiosis are:

1.) Prophase
2.) Metaphase
3.) Anaphase
4.) Telophase

Meiosis II

–  Starts after Meiosis I

–  Continues until metaphase II

–  When this meiosis II is finished then the result is ootid and a polar body

Maturation

–  Polar bodies dissolve leaving the only ootid

–  Ootid will mature into the ovum

The diagram below is from: http://www.biosci.uga.edu/almanac/