Oogonia go through____(i)____ during the first three months of fetal development, producing all the primary oocytes. Primary oocytes begin the process of meiosis but are halted in___(ii)____. Meiosis resumes, one oocyte at a time, beginning with the first ___(iii)______. This process is stimulated by ____(iv)_______. The secondary oocyte is arrested in ____(v)_____.
i Mitosis ii Prophase I iii Menstrual cycle iv FSH v Metaphase II
Oogonia go through mitosis during the early months of fetal development producing all the 2 million primary oocytes which are arrested at prophase I.These primary oocytes remain in this state till puberty. However, out of these only 60,000 to 80,000 survive till puberty while the rest degenerate. At the onset of puberty, meiosis resumes, one oocyte at a time, beginning with the first Menstrual cycle. Meiosis of the primary oocyte results in a secondary oocyte which is arrested in metaphase of meiosis II. This secondary oocyte completes its meiotic division only after the sperm binds to it.