Embryology of Genitalia Flashcards
Which layer of the TLD forms the female and male genitalia?
Intermediate Mesoderm
What is the indifferent stage?
When both the Wolffian and Muellerian ducts are present, so can’t tell the difference in sex of embryo
At what stage do embryo’s become different?
In 6th week, no longer indifferent
Why does mesonephric duct degenerate in a female?
Due to absence of testosterone
What causes the genital ridge to form ovarian tissue?
Due to lack of gonadal influence, with no Y chromosome, no sex determining region and no testis determining factor released
What does oestrogen stimulate?
Development of female external genitalia, and differentiation of Muellerian duct
What does the urogenital sinus develop into?
Female External Genitalia
What does the urethral fold develop into in a female?
Labia Minora
What does the genital tubercle form in a female?
Clitoris
What does genital swelling form in a female?
Labia Majora
What is the hymen formed from?
Urogenital Sinus
What is the primitive streak?
Depression in the epiblast
What is the SRY protein known as?
Testis Determining Factor: Male development takes place under its influence
Which cells are responsible for producing testosterone and at which week do they do this?
1) Interstitial cells of Leydig
2) Week 8
What does testosterone stimulate
Differentiation of Wolffian Duct
Why does Muellerian duct degenerate and what forms from this?
Inhibiting substance being released from Sertoli Cells
Utriculus Prostaticus
What does the Phallus form?
Elongation of Genital Tubercle
What does Genital swelling form in a male?
Scrotum
Where does the TLD differ in derivation of anal canal?
Endoderm: Upper 2/3
Ectoderm: Lower 1/3
When does anal membrane rupture?
In 7th week, so upper 2/3 can be continuous with lower 1/3 of anal canal
