R2 - Sexual Differentiation

Question 1

Sexual Differentiation

Answer 1

– SRY makes testes which make hormones that control everything to make a phenotypic “male”
– Absence of the above defaults to phenotypic “female”

Question 2

Determination of Genetic Sex

Answer 2

by chromosomal complement of sperm

-all oocytes are 23 X
-half of sperm are 23 Y and half are 23 X

sex determined at time of fertilization

Question 3

Primordial germ cells migrate to the gonadal ridges during the ____ weeks of gestation

Answer 3

4th‐5th
* This is necessary to make ovaries
* Testes can still form without germ cells but will never make sperm

Question 4

Recognizable testicular development antecedes ovarian development by ____

Answer 4

5‐6 weeks

Question 5

First sign of testicular development is appearance of ____ that migrate to form testicular cord

Answer 5

Sertoli cells

Question 6

____ form the interstices between the
seminiferous tubules, discernible at 60 days

Answer 6

Leydig cells

Question 7

Leydig cells are stimulated by maternal ____ and secrete _____

Answer 7

-hCG
-testosterone

Question 8

Sertoli cells secrete _____

Answer 8

ABP, inhibin and Anti‐ Mullerian Hormone (AMH)

Question 9

Not until the ____ week are structures recognizable as ovaries

Answer 9

10th‐11th

Question 10

Internal Genitalia
* Derived from Wolffian ducts in ___
* Derived from Mullerian ducts in ___
Both of these ducts develop alongside the ____

Answer 10

-“male”
-“female”

mesonephric bulb (mesonephros)

Question 11

Male external genitalia develop under influence of ____

Answer 11

dihydrotestosterone (DHT)