Reproductive Embryology

Question 1

Which ridge of the intermediate mesoderm makes the genital system?

Answer 1

Gonadal or genital ridge

Question 2

When is phenotypic sex made manifest?

Answer 2

Seventh week of development

Question 3

What gene is important for male phenotype? What does it produce?

Answer 3

SRY (sex determining region of Y)

Testis-determining factor

Question 4

What is the most common abnormality of sexual differentiation?

Answer 4

Klinefelter syndrome

Question 5

What is the genotype of klinefelter syndrome?

Answer 5

XXY genotype

Question 6

Are people affected by Klinefelter male or female?

Answer 6

Male, with femininization

Question 7

What are the symptoms of turner syndrome?

Answer 7

Short stature
High arched palate
Webbed neck
Shield-like chest
Inverted nipples
Cardiac and renal anomalies

Question 8

What is the genotype of Turner syndrome?

Answer 8

XO 45

Question 9

What genotype do true hermaphrodites have?

Answer 9

XX

Question 10

Where do gametes come from in development?

Answer 10

Umbilical vesicle (yolk sac)

Question 11

Where to gametes migrate to in development?

Answer 11

Genital ridge

Question 12

When does gamete migration happen? (what week)

Answer 12

5th week

Question 13

What do developing gonads consist of?

Answer 13

Mesothelium
Mesenchyme
Primordial germ cells

Question 14

What serve as the precursors to the Sertoli cells?

Answer 14

Cortical cords

Question 15

What do the cortical cords form?

Answer 15

Sertoli cells
Seminiferous tubules
Rete testis
Tubuli recti

Question 16

What do the mesonephric ductules become?

Answer 16

Efferent ductules, then distal epididymis

Question 17

What forms the interstitial cells of Leydig?

Answer 17

Mesenchyme

Question 18

_______ induces Sertoli cells to produce ________, which suppresses development of the ___________ ducts.

Answer 18

hCG induces
Anti-mullerian hormone (Mullerian inhibitor substance)
Paramesonephric (mullerian ducts)

Question 19

What does the indifferent sexual duct system consist of?

Answer 19

Mesonephric ducts (Wolffian)
Paramesonephric ducts (Mullerian)

Question 20

Where do the caudal ends of the paramesonephric ducts fuse?

Answer 20

Urogenital sinus

Question 21

What is the remnant of the paramesonephric duct called in males?

Answer 21

Prostatic utricle

Question 22

What stimulates the mesonephric duct to mature? What does it turn into?

Answer 22

Testosterone from interstitial cells

Epididymis, ductus deferens, ejaculatory duct

Question 23

What stimulates the development of the seminal vesicles? Where does it bud out from?

Answer 23

Testosterone

Ductus deferens

Question 24

What forms the prostate gland?

Answer 24

Epithelial outgrowth of pelvic urogenital sinus

Question 25

What forms the bulbourethral gland?

Answer 25

Epithelial outgrowth of spongy urethra (UG sinus)

Question 26

The absence of this allows paramesonephric duct development?

Answer 26

Anti-mullerian hormone

Question 27

When the two paramesonephric ducts fuse, what forms?

Answer 27

Uterovaginal primordium

Question 28

What forms the upper one-third of the vagina?

Answer 28

Uterovaginal primordium

Question 29

What forms the lower two-thirds of the vagina?

Answer 29

Urogenital sinus

Question 30

What are the female homologues of the bulbourethral glands?

Answer 30

Greater vestibular glands

Question 31

What causes mesonephric ducts to regress?

Answer 31

Lack of testosterone

Question 32

If the mesonephric ducts fail to regress completely in the female, what can result?

Answer 32

Gardner’s duct (perhaps cystic)