Urogenital Development
This practical will introduce the topic of urogenital differentiation during development through a series of online resource pages.
Aim: This practical is an introduction to the earliest events in Sexual Differentiation.
Key Concepts: Intermediate mesoderm, primordial germ cells, renal development, bladder development, gonad, internal genitalia, external genitalia, ovary, testes, puberty, hormonal changes, gametogenesis, abnormalities.
Background
Historic Gonad Images
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Two key systems, neural and reproductive, develop over an extended period from the early embryo to puberty and the emerging adult. The genital system is closely linked developmentally to the urinary system, often called the urogenital system. This practical will therefore cover early development of both system.
In understanding embryonic sexual development, think of a cascade of sequence dependent events that transform indifferent gonads, internal and external genitalia into distinct male and female structures.
The process begins with gonad differentiation, which itself is tied developmentally back at the initial event of fertilization and the presence of either a Y or X chromosome in the sperm.
The endpoint of development could be considered the post-puberty active reproductive system. Interestingly, recent research is pointing to a link between neural and reproductive systems in how male and female brains may differentially develop under the influence of sex hormones and perhaps even the sex chromosomes.
- There are 6 pages to work through in today's practical class, listed at the top and bottom of each page.
- Additional information sections are not part of the practical class content.
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Urogenital Timeline
- 24 days - intermediate mesoderm, pronephros primordial
- 28 days - mesonephros and mesonephric duct
- 35 days - uteric bud, metanephros, urogenital ridge
- 42 days - cloacal divison, gonadal primordium (indifferent)
- 49 days - paramesonephric duct, gonadal differentiation
- 56 days - paramesonephric duct fusion (female)
- 100 days - primary follicles (ovary)
Textbooks
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Moore, K.L. & Persuad, T.V.N. (2008). The Developing Human: clinically oriented embryology (8th ed.). Philadelphia: Saunders.
The following chapter links only work with a UNSW connection and can also be accessed through this UNSW Library connection.
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Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H. (2009). Larsen’s Human Embryology (4th ed.). New York; Edinburgh: Churchill Livingstone.
The following chapter links only work with a UNSW connection and can also be accessed through this UNSW Library connection.
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Hill, M.A. (2011) UNSW Embryology (11th ed.). Sydney:UNSW.
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