Development/Embryology

Question 1

What week are male and female external genitalia recognizable?

Answer 1

12

Question 2

What week is phenotypic differentiation complete?

Answer 2

20

Question 3

Where do primordial germ cells come from?

Answer 3

Endoderm of the yolk sac

Question 4

What is expressed on Primordial germ cells that guides their migration to the urogenital ridge?

Answer 4

C-kit receptor and stem cell factor (C-kit ligand)

Question 5

What is it called when there is a failure of PGCs to reach the genital ridge?

Answer 5

Gonadal dysgenesis

Question 6

What non primary kidney duct do males keep and what does it become?

Answer 6

Mesonephric (Wolff) duct - ductus deferens

Question 7

What non primary kidney duct do females keep?

Answer 7

Paramesonephric (Muller) duct

Question 8

What do Sertoli cells secrete to get rid of paramesonephric ducts?

Answer 8

Mullerian inhibitory Substance (Anti Mullerian hormone)

Question 9

What cells in the testes make testosterone and also make sure the mesonephric duct becomes the ductus deferens?

Answer 9

Leydig cells

Question 10

In order for the Sertoli cells to make sure the paramesonephric duct regresses, they first have to differentiate. This is under the control of what?

Answer 10

SOX9 and SF1

Question 11

Mutation in SOX9 causing short limbed dwarfism characterized by congenital bowing of long bones associated with skeletal and extra skeletal features like hypoplastic lungs, malformations of cervical spine, heart, and kidneys. Also male to female sex reversal

Answer 11

Campomelic dysplasia

Question 12

What has an important role in masculinization of external genitalia and prostate

Answer 12

DHT

Question 13

5-alpha-reductase has two isozymes. Which one is made by parts of the male reproductive tract?

Answer 13

5-alpha-reductase II

Question 14

What disorder has genetically male but they look female? (Intersexuality)

Answer 14

5 ARD

Question 15

In the development of the ovaries, what part of the gonads degenerate and what develops?

Answer 15

Medulla degenerates and cortex develops

Opposite in male gonads

Question 16

When the mesonephric duct doesn’t degenerate in a female, they are found in the mesentery of the ovary (broad ligament) and are called what?

Answer 16

Epoophoron and paroophoron (or Gartner’s duct)

Question 17

What is the gene that is found on the X chromosome but it repressed by the SRY in males and is responsible for controlling ovarian development?

Answer 17

DAX1

Question 18

What does DAX1 do?

Answer 18

Blocks SOX9 and AMH expression

Question 19

What upregulates DAX1?

Answer 19

WTN4

Question 20

What fuse together to form the uterus?

Answer 20

The 2 paramesonephric ducts

Question 21

Failure of the paramesonephric ducts to develop, resulting in missing uterine tubes, uterus, and variable malformations of the upper portion of the vagina is called what?

Answer 21

Mullerian (paramesonephric) agenesis or MRKH - Mayer-Rokitansky - Kuster- Hauser Syndrome

Question 22

Undescended Testes?

Answer 22

Cryptorchidism

Question 23

Incomplete fusion of urethral folds causing urethra to open onto the ventral aspect of the penis?

Answer 23

Hypospadias

Question 24

Urethral meat us opens on the Dorsey of the penis and often occurs with bladder exstrophy

Answer 24

Epispadias

Question 25

47 XXY, small testes, low levels of testosterone. Poorly developed secondary sexual characteristic and gynoxomastia (breast development). Elongated limbs.

Answer 25

Klinefelter syndrome

Question 26

45 X or 45X/46XX. Short stature, no adolescent growth spurt, broad chest, webbed neck, congenital heart disease. Ovary development is abortive.

Answer 26

Turner’s syndrome

Question 27

46XX or 46 XY. External genitalia of one sex accompanies gonads of the other sex

Answer 27

Pseudo intersexuality

Question 28

What week does phenotypic sexual differentiation begin?

Answer 28

7