This page introduces the uterus as part of the internal female reproductive tract development. Two paramesonephric ducts form from coelomic epithelium extending beside the mesonephric ducts. In the absence of Mullerian Inhibitory Factor these ducts proliferate and grow extending from the vaginal plate on the wall of the urogenital sinus to lie beside the developing ovary. The paired ducts begin to fuse from the vaginal plate end, forming the primordial body of the uterus and the unfused lateral arms form the uterine tubes.
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Paramesonephric ducts |
Early Fetal Structure |
Newborn Uterus |
Johannes Peter Muller (1801 – 1858) in 1830 was the first to described the duct named after him, the "Mullerian duct" also called the paramesonephric duct.
Page Links: Introduction | Some Recent Findings | Paramesonephric Duct | Development Overview | Movies | Fetal Uterus | Fetal Uterus Growth | Uterine Tubes | Uterine Blood Supply | Abnormalities | Molecular | References | Glossary
Related Pages: Genital System - Female | Week 1 Notes - Oogenesis | X chromosome | Human Menstrual Cycle |
Deutscher E, Hung-Chang Yao H. Essential roles of mesenchyme-derived beta-catenin in mouse Mullerian duct morphogenesis. Dev Biol. 2007 May 3; [Epub ahead of print] (More? Molecular)
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."
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."
Mullerian ducts have three elements:
1. a canalised epithelial tube
2. mesenchymal cells surrounding the tube
3. coelomic epithelial cells.
Anterior view of development of the female uterus and vagina between Week 9 and 20. The paramesonephric ducts (red) fuse in the midline to form the genital canal. The urogenital sinus (yellow), in contact with the paramesonephric duct, thickens to form the sinusal tubercle which extends as a solid vaginal plate, then becomes hollow as the sinovaginal bulb, finally forming the vagina. Female Internal Genitalia (288 Kb) |
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Common |
Female |
Internal Genital Tract Differentiation |
Müllerian Duct (paramesonephric) - blue (This historic image mislabels the vaginal origin) |
The data below gives an overview of the timecourse of embryonic human uterine development.
stage 18 - Müllerian duct to the coelomic cavity was formed as the result of an invagination of the coelomic epithelium
stages 19-23 - duct grows independently from the invagination
week 20 - uterine horn fimbrial development begins and continues after birth
Data: Hashimoto R. Development of the human Mullerian duct in the sexually undifferentiated stage. Anat Rec A Discov Mol Cell Evol Biol. 2003 Jun;272(2):514-9.
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Urogenital sinus of female human embryo of eight and a half to nine weeks old (From model by Keibel) (Image: Gray's Anatomy) |
(Image modified from: Drews U, Sulak O, Schenck PA. |
Graph shows the growth during the fetal period of the uterus between week 19 and 38. |
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During this time the uterine circumferunce increases from about 20 mm to just under 60mm and the width increases from less than 10mm to just over 20 mm. Uterine horn fimbrial development begins after week 20 and continues after birth. Uterine growth continues postnatally, increasing outer muscle thickness and cyclic changes in the lining with puberty. Adult external uterine orifice to the fundus is approximately 6.25 cm. |
(Data: Soriano D, Lipitz S, Seidman DS, Maymon R, Mashiach S, Achiron R. Development of the fetal uterus between 19 and 38 weeks of gestation: in-utero ultrasonographic measurements. Hum Reprod. 1999 Jan;14(1):215-8. and other sources) |
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(Image: Gray's Anatomy)
The unfused portion of the paramesonephric ducts will form the uterine tubes. Note that there are several synonyms used for the paired uterine tubes or Fallopian tubes or oviducts or uterine horns.
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In the adult, the uterine tube has been described in 4 anatomical regions.
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Peritoneal view of uterus body and tubes |
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Developing uterine tube (cat) showing relationship to ovary and degenerating mesonephros. |
(Images: UWA Blue Histology - Female Reproductive Tract)
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A range of uterine and vaginal anatomical anomalies based upon the abnormal development and fusion of the paramesonephric ducts and vaginal plate development.
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Unicornate Uterus - failure of the paramesonephric ducts to fuse. A single paramesomnephric duct has fused with the vaginal plate and now opens into the vagina, while the other forms a diverticulum. |
Uterine Duplication (uterus didelphys, double uterus, uterus didelphis) A rare uterine developmental abnormality where the paramesonephric ducts (Mullerian ducts) completely fail to fuse generating two separate uterus parts each connected to the cervix and having an ovary each.
Septate Uterus
Cervical: cervical agenesis, cervical duplication
Vaginal: Mayer-Rokitansky syndrome (MRK anomaly, Rokitansky-Küster-Hauser syndrome, RKH syndrome, RKH) congenital absence of the vagina, dyspareunia, vaginal agenesis.
Environmental Abnormalities
DES Diethylstilbestrol or diethylstilbetrol, is a drug that was prescribed to women from 1938-1971 to prevent miscarriage in high-risk pregnancies. The drug acted as a potent estrogen (mimics natural hormone) and therefore could also act as a potential endocrine disruptor. This led to a number of developing fetal reproductive tract and other abnormalities. In the female fetus, it increased risk of abnormal reproductive tract and also carcinogenic (cancer forming). In the male fetus, it increased the occurance of abnormal genitalia. The drug was banned by FDA (USA) in 1979 as a teratogen, it had previously also been used as livestock growth promoter and could have potentially entered the human food chain. (More? Endocrine Abnormalities | Abnormal Development - Drugs)
Links: Endocrine Abnormalities | Abnormal Development - Drugs | Childrens Hospital Boston - Congenital Anomalies of the Uterus | Medical Education Image Link - Cervical agenesis | OMIM - Rokitansky-Küster-Hauser syndrome |
The embryonic origin of the vagina has been a hotly debated issue with several different cotributions and origins described.
One description shows the vagina arising by downward growth of Wolffian and Mullerian ducts. The sinovaginal bulbs are the caudal ends of the Wolffian ducts. Vaginal development is also under negative control of androgens.
An earlier understanding was that the upper part of the vagina derived from Müllerian ducts and the lower part from the sinovaginal bulbs (formed by fusion form the vaginal plate) all derived from the urogenital sinus. The terms sinovaginal bulbs and vaginal plate were first coined by Koff in 1933.
References:
Koff AK. Development of the vagina in the human fetus. Contributions to Embryology No. 140, Carnegie Inst. 1933; 24:61–90.
Wnt genes - Wnt4, Wnt5a, and Wnt7a implicated in the formation and morphogenesis of the Müllerian duct.
Wnt7a - mediates the patterning of the oviduct and differentiation of the uterus.
beta-catenin - manufactured in the mesenchyme is a downstream effector of Wnt7a.
Bmp2 - decidualization regulator of gene expression and function (shown in mouse uterus).
Lim1, Lhx9, Emx, Pax-2, Hox-A9, Hox-A10, Hox-A11, Hox-A13, WT1, SF-1, GATA-4. TGF-beta
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.
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.
Articles
Deutscher E, Hung-Chang Yao H. Essential roles of mesenchyme-derived beta-catenin in mouse Mullerian duct morphogenesis. Dev Biol. 2007 May 3; [Epub ahead of print] (More? Molecular)
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. Hashimoto R. Development of the human Mullerian duct in the sexually undifferentiated stage. Anat Rec A Discov Mol Cell Evol Biol. 2003 Jun;272(2):514-9. Soriano D, Lipitz S, Seidman DS, Maymon R, Mashiach S, Achiron R. Development of the fetal uterus between 19 and 38 weeks of gestation: in-utero ultrasonographic measurements. Hum Reprod. 1999 Jan;14(1):215-8.
Search PubMed
Search May 2007 "embryonic uterine development" 3,025 reference articles of which 491 were reviews.
Search PubMed: term = embryonic uterine development | Uterine Development | Paramesonephric Duct | Mullerian Duct | Endocrine Disruptors
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This page introduces the early development of the internal female genital tract, development of the uterus. The paramesonephric (Mullerian) ducts are an initially paired duct system, preserved in female internal genital tract development and lost in males.
Please email Dr Mark Hill if you wish to make a comment about this current project.
