2014 Group Project 4
| 2014 Student Projects | ||||
|---|---|---|---|---|
| 2014 Student Projects: Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Group 6 | Group 7 | Group 8 | ||||
| The Group assessment for 2014 will be an online project on Fetal Development of a specific System.
This page is an undergraduate science embryology student and may contain inaccuracies in either description or acknowledgements. | ||||
Genital
System Development
[NB: having formatting issues trying to put the following information into a table, an attempt at the table is included below]
- the initial stages of genital development are indifferent, both males and females are anatomically identical until morphological changes occur beginning at week 7
- males and female changes are determined by the chromosomal sexual differentiation which occurs at fertilisation
- initial stages of gonadal development begins during the fifth week of development. First change is a thickened area of mesothelium on the medial side of the mesonephros [primitive kidney]
- this proliferation + underlying mesenchyme produces a bulge known as the GONADAL RIDGE
- finger like epithelial chords [gonadal chords] grow into underlying mesenchyme
- This who structure is referred to as an indifferent gonad
- indifferent gonad consists of an external cortex and internal medulla
- in embryos with an XX sex chromosome, the cortex of the indifferent gonad progresses to developing into an ovary
- Conversely, embryos with an XY chromosome, the medulla of the indifferent gonad progresses into a testes
- CHROMOSOMAL SEX DETERMINATION - the indifferent gonads differ after the seventh week by the presence the SRY gene which produces the TESTES DTEREMINING FACTOR on the short arm of the Y Chromosome. Under this influence, the gonadal chords differentiate to somniferous cords expression of Sox9 and Fgf9
- once the gonad that develops [ovary or testes] then determines the type of sexual and genital differentiation which occurs
- fetal testes produce testosterone, dihydrotestosterone and anti mullerian hormone
- TESTES DEVELOPMENT -- insert picture here
- seminferous chords --> rete testes - development of dense tunica albiguinea- enlarging testes separate from the degenerating mesonephros to form the somniferous tubules, tubuli, recti and rate testis - seminferous tubules --> interstitial cells [leydig cells] which produce androgens - insert diagram showing the production of androgens (testosterone, dihydrotestosterone and antimullerian hormones (sertoli cells) )
- DEVELOPMENT OF OVARIES
- ovary not identifiable until 10th week - gonadal chords aren't prominent in developing ovary but extend to medulla and form the rate ovary OOGENESIS DIAGRAM
- DEVELOPMENT OF GENITAL DUCTS
- fifth and sixth weeks - mesonephric ducts (wolfing duct) and paramesonephric ducts (mullein ducts)
