Development Of Reproductive Tracts Flashcards

1
Q

What happens 30 hours after fertilisation?

A

Fertilised egg splits into two blastomeres

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2
Q

How many divisions until the oocyte becomes the morula?

A

4 (16 cells)

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3
Q

What structure originating from the hindgut becomes the common opening of the reproductive and urinary tracts?

A

Cloaca - Urogenital sinus

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4
Q

How does the SRY region of the Y chromosome determine sex?

A

Producing a transcription factor initiating a cascade of downstream genes (testis determining factor TDF)

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5
Q

What is the first step of the development of the reproductive system?

A

Primordial germ cells migrate along retro peritoneum to the gonad at the urogenital ridge

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6
Q

What three sources make up the gonad?

A

Mesothelium
Underlying mesenchyme
Primordial germ cells

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7
Q

Which cords develop in males?

Which cords develop in females?

A

Medullary cords

Cortical cords

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8
Q

Which duct persists in males?

Which duct persists in females?

A

Mesonephric (Wolffian) duct

Paramesonephric (Mullerian) duct

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9
Q

What structures does the mesonephric duct become if stimulated by androgens?

A

Rete testis and vas deferens

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10
Q

What dictates the prescence of each duct?

A

Mesonephric - prescence of androgens from testes

Paramesonephric- abscence of androgens and MIH secreted by testes

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11
Q

How do the male external genitalia form?

A

Genital tubercle elongates
Genital folds fuse to form spongy urethra
Genital tubercle develops into glans penis

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12
Q

How do the external genitalia of the female form?

A

No fusion of genital folds gives rise to labia majors and minora
Genital tubercle develops into clitoris

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13
Q

What drives the descent of the gonads in males and females? Why can the female genitalia not descend?

A

Gubernaculum (caudal genital ligament)

Uterus prevents descent of the ovary in females, and the gubernaculum degenerates forming the round ligament

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14
Q

What does a person of 45X0 makeup suffer from?

What are the clinical signs?

A

Turners syndrome

Short stature, high arched palate, webbed neck, shield like chest, cardiac and renal abnormalities, inverted nipples

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15
Q

What is Klinefelter syndrome?

What are some clinical signs?

A
Karyoptype 47 XXY or XXXY etc
Decreased fertility
Small testes
Low testosterone levels
Gynecomastia (enlarged breasts) in 33%
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16
Q

What is the most common cause of ambiguous genitalia?

A

Congenital adrenal hyperplasia - genetically female but exposed to androstenedione by the adrenal glands causing external masculisation of genitalia

17
Q

What’s the most common cause of sexual ambiguity in males?

A

Androgen insensitivity syndrome - lack of androgen receptors in tissue
Note: testes still produce MIH so paramesonephric system is still supressed