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CHAPTER 22: THE REPRODUCTIVE SYSTEMS

V.THE FEMALE REPRODUCTIVE SYSTEM

A.OrgansSee Fig 22.19, page 899.

1.OVARIES  =the primary female sex organs which produce ova (eggs) and female sex hormones.

a.solid ovoid structures located (one on each side) on the posterior wall of the pelvic cavity.

b.  Internal StructureFig 22.24, page 903.

 Each ovary is subdivided into a

1.medulla    =CT, blood & lymph vessels and nerves;

     = nourishment and support.

2.  cortex       =ovarian follicles covered by germinal epithelium.

c.Oogenesis:See Fig 22.21a, page 901.

Mitosis of primordial germ cells within female embryos produces diploid oogonia (23 pairs of chromosomes), which duplicate their DNA and give rise to

Primary oocytes (23 pairs of duplicated chromosomes)

1.Note that human females are born with all their potential ova as primary oocytes.

At puberty, once each month, FSH stimulates one primary oocyte to undergo Meiosis I, which gives rise to one

Secondary oocyte (23 duplicated chromsomes) and a polar body due to unequal cytokinesis.  The secondary oocyte is then ovulated from the ovary (LH)

1.If the secondary oocyte is penetrated by a sperm cell is Meiosis II initiated.

2.When and if Meiosis II is complete,

a second polar body is separated from the

large ovum (23 chromsomes),

The haploid nuclei of the sperm and the now-matured ovum fuse.

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