HD - Control of sexual determination

What are the three main stages of sexual development?
Gonad formation, Gonad determination, sexual differentiation
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What does the urogenital ridge divide in to?
Nephrogenic and gonadal ridge
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What does the nephrogenic ridge divide in to?
Mesonephric ducts (Wolffian) and precursors of the urinary system
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What develops from further invagination of the intermediate mesoderm?
Paramesonephric ducts (Mullerian)
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What cells migrate to the gonadal ridge to develop into gonads?
Primordial germ cells
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What transcription factor codes for SF1
Nr5a1
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What is the testes determining factor?
SRY
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What is on the tips of the long and short arms of the X chromosome?
PAR1 and 2
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Where is SRY located?
Adjacent to the centomeric portion of PAR1
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SRY binds to SF1 to upregulate what?
Sox9 - which then continues to up regulate itself
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Where is sox9 found?
C17
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Is sox9 dosage sensitive?
Yes - you need 2 copies
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Where is DAX1 found?
X chromosome
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What is the role of DAX1?
Represses testes development
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Is DAX1 dosage sensitive?
Yes - why XXY affects male sexual development. Duplicates lead to DSD in an XY individual
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What occurs if Wnt4;Ctnnb1 is absent in an ** individual?
The bi-potential keeps trying to become a teste
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What is the definition of sexual differentiation?
Process where the gonads secrete local and hormonal factors to drive differentiation of: external genitalia, internal reproductive organs and extra gonadal tissue
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What do we mean by internal structures?
Mullerian and Wolffian ducts
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What do we mean by external structures?
Genital tubercles and labia-scrotal folds
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All foetuses have the same Genital development till around what week?
Week 8 I.u.
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What hormone leads to regression of Müllerian ducts?
AMH
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Testosterone promotes the development of Wolffian ducts into what?
Epididymis, vas deferens, seminal vesicles
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What is the more potent form of testosterone?
Androgen Dihydrotestosterone (DHT)
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DHT promotes the development of what?
Genital tubercles, labia-scrotal folds and urogenital sinus into - penis, scrotum and prostate
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What does the Müllerian duct develop into?
Fallopian tubes, uterus and upper vagina
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What does the genital tubercle, labia-scrotal fold and urogenital sinus develop in to?
Lower vagina and ***** ********
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What is Klienfelter syndrome? (including clinical features - 6)
XXY - undescended testes, tall stature, pea-sized testes, lack of secondary characteristics, gynaecomastatia, infertility
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What would be the clinical features of someone ** with an SRY translocation?
Present after puberty with short stature, gynaecomastatia, small testes, fertility issues. Treat with testosterone
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What is 5-a-reductase involved in?
The production of DHT
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Clinical features of 5-a-reductase deficiency?
Genitalia appearance looking in-between / leaning towards female appearance. Internal structures are male with vague external, till at puberty increased androgen levels lead to virilisation of external genitalia
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Other cards in this set

Card 2

Front

What does the urogenital ridge divide in to?

Back

Nephrogenic and gonadal ridge

Card 3

Front

What does the nephrogenic ridge divide in to?

Back

Preview of the front of card 3

Card 4

Front

What develops from further invagination of the intermediate mesoderm?

Back

Preview of the front of card 4

Card 5

Front

What cells migrate to the gonadal ridge to develop into gonads?

Back

Preview of the front of card 5
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