This page introduces female gonad (ovary) and reproductive tract development. Johannes Peter Muller (1801 – 1858) in 1830 was the first to described the "Mullerian duct" also called the paramesonephric duct. This initially paired duct system is preserved in female development and lost in males.
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Female Gonad (ovary) Development (228 Kb) |
Female Internal Genitalia (288 Kb) |
Female External Genitalia (288 Kb) |
(Clicking image or text will open movie, more movies can be seen on the Urogenital Movies page)
Initial gonad development in females and males is virtually identical with germ cells migrating into an indifferent gonad. It is only the presence of a Y chromosome in males, that then leads to testis development. In females with XX, the ovary begins to develop. The subsequent structure and timecourse of germ cell then differs between males and females. In the ovary oocytes proliferate prior to birth and arrest in meiosis 1.
Infant Ovary, note the large number of primordial follicles around the cortex.
Page Links: Introduction | Some Recent Findings | Infant Ovary | Oogenesis | Development Overview | Mouse Oogenesis | Paramesonephric Duct | Movies | References | Glossary
Related Pages: Uterus Development | Week 1 Notes - Oogenesis | X chromosome | Human Menstrual Cycle
Guioli S, Sekido R, Lovell-Badge R. The origin of the Mullerian duct in chick and mouse. Dev Biol. 2007 Feb 15;302(2):389-98.
"In vertebrates the female reproductive tracts derive from a pair of tubular structures called Mullerian ducts, which are composed of three elements: a canalised epithelial tube, mesenchymal cells surrounding the tube and, most externally, coelomic epithelial cells. ... We show that all Mullerian duct components derive from the coelomic epithelium in both species. Our data support a model of a Mullerian epithelial tube derived from an epithelial anlage at the mesonephros anterior end, which then segregates from the epithelium and extends caudal of its own accord, via a process involving rapid cell proliferation. This tube is surrounded by mesenchymal cells derived from local delamination of coelomic epithelium."
Eppig et al., 2002 has shown that in the ovary, it is the oocyte (egg) that regulates the development of the ovarian follicle (the surrounding cells).
Image below shows a region (see inset) of the infant ovary cortex. There are a large number of developing oocytes which will eventually form a dense primordial germ layer at the ovary periphery. Later stages of follicle development are completely absent and will begin to only appear just prior to puberty. (More? The Ovary)
(Image: modified from Virtual Microscope)
The graph below shows the changes in human germ cell numbers in the ovary with age, peaking at about 7 million (occuring in early fetal development) and then decreasing by apopotic cell death. At puberty there remain only about 400,000 and only about 10% of these will be released through reproductive life.
(Based on data from: Hassold, etal., Environ Mol Mutagen 1996. 28: 167-175)
The table below gives an overview of the timecourse of human ovary development (see also Movies).
Developmental Age |
Feature |
Day 28 |
first primordial germ cells observed |
Week 4-7 |
germ cell proliferation and migration |
Week 4-5 (day 28-30) |
mesonephric tubules form |
Week 4-5 (day 28-30) |
mesonephric ducts (Wolffian) forms |
Week 5 (day 31-35) |
genital ridge forms from coelomic epithelium thickening |
Week 6 (day 35-42) |
germ cells migrate to dorsal mesentry |
Week 6 (day 38-42) |
budding indifferent gonad |
Week 6 (day 40-42) |
paramesonephric duct (Mullerian) forms |
Week 7 (day 42-48) |
germ cells migrate into indifferent gonad |
Week 7 (day 49) |
germ cell migration complete |
Weeks 7-8 |
gonad recognisable as ovary |
Months 2-7 |
Oogonia proliferate in ovary |
Months 2.5-7 |
Oocytes initiate meiosis and then arrest |
(table modified from: Kavlock R, Cummings A., 2004 data originally from Parrott JA, Skinner MK., 1999)
In the mouse, female germ cells enter into prophase of first meiotic division as a mid-gestational hallmark of gender. Perinatally oocytes interact with granulosa cells to form primordial follicles, with cyclic periodicity enter a 3 week growth phase that culminates in meiotic maturation and ovulation. Genes expressed in oocytes encode maternal factors that control many of these processes.
(Text modified from: A Amleh and J Dean, Human Reproduction Update Vol8 No5 pp395-403, 2002)
The Mullerian duct (= paramesonephric duct, preferred terminology) paired ducts that form the epithelial lining of female reproductive organs: utererine tube, uterus, upper vaginal canal. The term "paramesonephric" duct means beside the mesonephric (Wolffian) duct, which is its anatomical location in early development. Mullerian refers to Johannes Peter Müller (1801-1858) a German scientist who specialised in comparative anatomy. These ducts initially form and then degenerate in the male.
A recent study using both chicken and mouse embryos has shown that these initially paired tubular structures derive from the coelomic epithelium. Guioli S, Sekido R, Lovell-Badge R. The origin of the Mullerian duct in chick and mouse. Dev Biol. 2006 Oct 3
"Mullerian epithelial tube derived from an epithelial anlage at the mesonephros anterior end, which then segregates from the epithelium and extends caudal of its own accord, via a process involving rapid cell proliferation. This tube is surrounded by mesenchymal cells derived from local delamination of coelomic epithelium."
The broad ligament is found associated with the internal human female genital tract. It forms a mesentery consisting of a double fold of the peritoneum that connects the uterus to the peritoneal floor and walls. Anatomically it has three parts:
Abnormalities include peritoneal endometriosis. |
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The list below shows the embryonic origins of various female genital structures.
ectoderm - cutaneous epithelia of mons pubis, labia, and clitoris (keratinized stratified epithelium)
endoderm - mucosa of the vulvar vestibule (non-keratinized stratified epithelium)
mesoderm - vagina
(More? Farage M, Maibach H., 2006)
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Female Gonad (ovary) Development (228 Kb) |
Female Internal Genitalia (288 Kb) |
Female External Genitalia (288 Kb) |
(Clicking image or text will open movie, more movies can be seen on the Urogenital Movies page)
Links: Reviews | Articles | Online Textbooks | Search Textbooks | Search PubMed | Glossary
Reviews
Farage M, Maibach H. Lifetime changes in the vulva and vagina. Arch Gynecol Obstet. 2006 Jan;273(4):195-202.
Pannetier M, Mandon-Pepin B, Copelli S, Fellous M. [See Related Articles] Molecular aspects of female and male gonadal development in mammals. Pediatr Endocrinol Rev. 2004 Mar;1(3):274-87.
Kavlock R, Cummings A [See Related Articles] Function of sexual glands and mechanism of sex differentiation. J Toxicol Sci. 2004 Aug;29(3):167-78. Review.
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Search Feb 2007 "Ovary Development" 14502 reference articles of which 1728 were reviews.
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This page introduces the early development of the female genital system which includes ovary, genital tract and external genitalia.
The male and female reproductive systems develop initially "indifferently". The absence of the Y chromosome SRY gene allows the development of female genital structures.
Please email Dr Mark Hill if you wish to make a comment about this current project.
