Embryological Development of Sex Flashcards

1
Q

When does the ‘genital ridge’ develop?

A

3.5-4 weeks

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2
Q

From what are the gonads developed from?

A

A common, bipotential genital primordium together with 3 invading/migratory cell types: 1) PGCs; 2) germinal epithelial cells and; 3) mesonephric cells

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3
Q

From what is the common, bipotential genital primordium formed?

A

Mesenchymal cells/tissue

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4
Q

Where is the gonadal ridge found?

A

The posterior abdominal wall

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5
Q

When are PGCs first identifiable?

A

3 weeks

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6
Q

Where are the PGCs found pre-migration?

A

The yolk sac, near the base of the developing allantois

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7
Q

From what are PGCs derived?

A

The epiblast

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8
Q

When is migration of the PGCs complete?

A

6 weeks

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9
Q

When are PGCs arrested in males?

A

Mitosis

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10
Q

When are PGCs arrested in females?

A

Prophase I of meiosis

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11
Q

From where do the germinal epithelial cell originate?

A

They originally overly the mesenchymal cells of the genital ridges

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12
Q

What do the germinal epithelial cells form?

A

The primitive sex cords

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13
Q

Do the germinal epithelial cells/primitive sex cords express sry?

A

Yes

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14
Q

Do the PGCs express sry?

A

No

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15
Q

Do the mesonephric cells express sry?

A

No

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16
Q

Which cell types expresses sry?

A

The germinal epithelial cells/primitive sex cords

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17
Q

Where is sry located?

A

Near the end of the short arm of the Y chromosome

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18
Q

What is the function of sry?

A

Sry is the ‘controller’ gene - it determines whether or not testis develop (by determining whether or not Sertoli cells develop)

19
Q

What do the primitive sex cords become in males?

A

The testis cords

20
Q

What do the germinal epithelial cell of the primitive sex cords ultimately form in males?

A

Sertoli cells

21
Q

What is the action of sry mediated by?

A

Sox9

22
Q

What does Sox9 stimulate the production of?

A

1) AMH; 2) PGD2; 3) Fgf9

23
Q

What is the function of Fgf9?

A

= a chemoattractant for the mesonephric cells to the gonadal ridges

24
Q

What is the function of AMH?

A

AMH ensures the formation of the male internal genital tract from the Wolffian ducts

25
Q

From where do the mesonephric cells originate?

A

Lateral to the gonadal ridges

26
Q

What do the mesonephric cells form in males?

A

1) Vasculature; 2) Leydig cells; 3) Myoid cells

27
Q

What do the mesonephric cells form in females?

A

1) Vasculatrue; 2) Theca cells

28
Q

What does the clustering of the primitive sex cords result in in females?

A

Primordial ovarian follicles

29
Q

What do the germinal epithelial cells of the primitive sex cords ultimately form in females?

A

Granulosa cells

30
Q

What genes maintain ovarian development?

A

Wnt4 and Foxl2

31
Q

What inhibits Wnt4 and Foxl2?

A

Sox9

32
Q

From what do the male internal genitalia develop?

A

Wolffian ducts

33
Q

From what do the female internal genitalia develop?

A

Mullerian ducts

34
Q

Which cell type produces AMH?

A

Sertoli cells

35
Q

Which cell type produces androgens?

A

Leydig cells

36
Q

What is the action of AMH on the Mullerian ducts in males?

A

The PRESENCE of AMH in males results in the regression of the Mullerian ducts

37
Q

What is the action of the absence of AMH on the Mullerian ducts females?

A

The ABSENCE of AMH in females allows the Mullerian ducts to persist

38
Q

What do the Wolffian ducts form in males?

A

1) Epididymis; 2) vas deferens; 3) prostate

39
Q

What do Mullerian ducts from in females?

A

1) Oviducts; 2) uterus; 2) upper 2/3rds of the vagina; 4) cervix

40
Q

What do the urethral folds form in males?

A

The penile shaft

41
Q

What des the genital swellings/labioscrotal swellings form in males?

A

The scrotum

42
Q

What does the genital tubercle form in males?

A

The glans penis

43
Q

What doe the urethral folds and genital swellings/labioscrotal swellings form in females?

A

The labia majora and minora

44
Q

What doe she genital tubercle form in females?

A

The clitoris