Genital - Male Development: Difference between revisions
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* '''Penile biometry on prenatal MR imaging''' <ref><pubmed>21484906</pubmed></ref>"Mean length values, including 95% confidence intervals and percentiles, were defined. Penile length as a function of gestational age was expressed by the regression equation: outer mean length= -5.514 + 0.622 *, and total mean length= -8.865 + 1.312 * (*= GW). The correlation coefficients were statistically significant (p < .001). The comparison between outer length on MRI and US data showed no significant differences, whereas total length on MRI and US data demonstrated significant differences (p< .001)." | |||
* '''Male reproductive tract abnormalities: More common after assisted reproduction?'''<ref><pubmed>20674196</pubmed></ref> "IVF and ICSI, by increasing the risks of prematurity, low birthweight, and multiple gestation, are indirect risk factors for developing male genital malformations. In infants with normal birhtweight or from singleton pregnancies, ICSI is a specific risk factor for hypospadias." | * '''Male reproductive tract abnormalities: More common after assisted reproduction?'''<ref><pubmed>20674196</pubmed></ref> "IVF and ICSI, by increasing the risks of prematurity, low birthweight, and multiple gestation, are indirect risk factors for developing male genital malformations. In infants with normal birhtweight or from singleton pregnancies, ICSI is a specific risk factor for hypospadias." | ||
Revision as of 17:19, 16 April 2011
Introduction
The male and female reproductive systems develop initially "indifferently", it is the product of the Y chromosome SRY gene that makes the "difference". The mesonephric duct (Wolffian Duct) contributes the majority of male internal genital tract.
Embryonic gonad development leads to the mesonephric/paramesonephric duct changes, while the external genitaila remain indeterminate in appearance through to the fetal period.
Importantly its sex chromosome dependence, late embryonic/fetal differential development, complex morphogenic changes, long time-course, hormonal sensitivity and hormonal influences make it a system prone to many different abnormalities.
There are also currently separate pages describing Spermatozoa Development | Testis Development | Prostate Development.
| Puberty
Some Recent Findings
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Textbooks
- Human Embryology (2nd ed.) Larson Chapter 10 p261-306
- The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud Chapter 13 p303-346
- Before We Are Born (5th ed.) Moore and Persaud Chapter 14 p289-326
- Essentials of Human Embryology, Larson Chapter 10 p173-205
- Human Embryology, Fitzgerald and Fitzgerald Chapter 21-22 p134-152
- Developmental Biology (6th ed.) Gilbert Chapter 14 Intermediate Mesoderm
Movies
Genital development animations
Urogenital Sinus | Urogenital Septum |
Male External | Testis Descent |
Primordial germ cell migration (mouse)
Migration 1 | Migration 2 | Migration 3 |
Development Overview
Three main stages during development, mesonephric/paramesonephric duct changes are one of the first male/female differences that occur in development, while external genitaila remain indeterminate in appearance for quite a while.
- Differentiation of gonad (Sex determination)
- Differentiation of internal genital organs
- Differentiation of external genital organs
The 2nd and 3rd stages dependent on endocrine gonad. Reproductive development has a long maturation timecourse, begining in the embryo and finishing in puberty. (More? Puberty Development)
Historic Images of Genital Changes
Urogenital indifferent | Urogenital male | Urogenital female |
Gonad - Testis
- Links: Testis Development
Internal Genital
External Genital
Additional Images
Stages of primordial germ cell migration[5]
References
Reviews
Articles
Search PubMed
Search Pubmed: Male Genital System Development | mesonephric duct
Terms
- mesonephric duct - (Wollfian duct) An early developing urogenital paired duct system that initially runs the length of the embryo, that will differentiate and form the male reproductive duct system (ductus deferens). In females, this duct degenerates occasionally some remnants may remain associated in broad ligament.
- Wolffian duct - (mesonephric duct, preferred terminology), A developmental duct that runs from the mesonephros to cloaca. The duct in male differentiates to form the ductus deferens and in female the same structure regresses. Historically named after Caspar Friedrich Wolff (1733-1794), a German scientist and early embryology researcher and is said to have established the doctrine of germ layers. (More? Caspar Friedrich Wolff)
Glossary Links
- Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link
Cite this page: Hill, M.A. (2024, April 24) Embryology Genital - Male Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Genital_-_Male_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G