Development Of The Genital System

Question 1

At what week can the male and female external genitalia be recognized?

Answer 1

Week 12

Question 2

By what week should all the phenotypic differentiation be complete?

Answer 2

Week 20

Question 3

Where do the primordial germ cells reside in the developing fetus?

Answer 3

Endoderm of yolk sac

Question 4

What guides migration of the primordial germ cells?

Answer 4

C-kit receptor and stem-cell factor

Question 5

What is the karyotype of an individual that has pure gonadal dysgenesis?

Answer 5

Normal, just problem with specific gene on a chromosome due to failure of PGC migration.

Question 6

Where do the PGCs migrate too?

Answer 6

Primitive sex cords

Question 7

The ductus deferens is a remnant of what?

Answer 7

Mesonephric duct

Question 8

Gonads, kidneys, and supra renal glands are derived from what tissue?

Answer 8

Intermediate mesoderm

Question 9

What ducts are kept by the male and female?

Answer 9

Male- mesonephric duct

Female- paramesonephric duct

Question 10

What determines the sex of a male?

Answer 10

SRY on the Y chromosome. Synthesis will trigger male development.

Question 11

What two effects does testosterone have in the normal developing male fetus?

Answer 11

Descent of testes into the scrotum.

Mesonephric duct-> epididymis, seminal vesicles, ductus deferens.

Question 12

What could be the cause of a genitic male with female secondary sex characterists?

Answer 12

Defect in the 5 alpha reductase.

Question 13

What does SRY/ TDF act upon?

Answer 13

Sertoli cells

Question 14

What are the two molecules that are required for Sertoli cell differentiation and normal male sexual development?

Answer 14

SOX9, SF1

Question 15

What is the result of stimulation of the Sertoli cells in males?

Answer 15

Production of Mullerian inhibitory substance and regression of the paramesonephric ducts.

Question 16

What is the result when there is a mutation in SOX9?

Answer 16

Campomelic dysplasia. Can have female sex characteristics.

Question 17

What does the urogenital sinus become in males and females?

Answer 17

Male- urethra, prostate. Closes in response to DHT.

Female- lower vagina vestibule.

Question 18

What does the genital tubercle become in the male and female?

Answer 18

Male- penis

Female- clitoris

Question 19

What does the labioscrotal swellings become in the male and female?

Answer 19

Male- scrotum.

Female- vulva.

Question 20

What is lost in the developing ovary?

Answer 20

Medulla and mesonephric duct.

Question 21

What are the remnants of the mesonephric duct in the female and where can they be found?

Answer 21

Epoophoron and paroophoron. Found in the mesentary of the ovary.

Question 22

What signaling molecule in the female blocks the action of SOX9 and AMH expression?

Answer 22

DAX 1

Question 23

The uterus and upper portion of the vagina are formed via what structures coming together?

Answer 23

Paramesonephric duct.

Question 24

What tissue contributes to the formation of the lower 1/3 of the vagina?

Answer 24

Posterior wall of the urogenital sinus. AKA tissue of sinovaginal bulbs

Question 25

How can a 46, XY have persistence of the paramesonephric ducts and female sexual characteristics?

Answer 25

Circulating levels of AMH are low or there is an abnormal response to normal AMH.

Question 26

What is the failure of paramesonephric ducts to develop called in a female?

Answer 26

MRKH- Mayer-Rokitansky-Kuster-Hauser Syndrome.

Question 27

What divides the cloacal membrane and anal membranes?

Answer 27

Urorectal septum

Question 28

What is the term for undescended testes?

Answer 28

Cryptrochidism

Question 29

what is the name of the incomplete fusion of the urethral folds?

Answer 29

Hypospadias.

Question 30

What are the four types of hypospadias?

Answer 30

Glandular, penile, penoscrotal, perineal.

Question 31

What is it called when the urethral meatus opens on the dorsum of the penis?

Answer 31

Epispadias

Question 32

What is klinefelters syndrome?

Answer 32

- 47 XXY. - characterized by small testes, low levels of testosterone. - poorly developed secondary sexual characteristics, gynecomastia.

Question 33

What is turners syndrome?

Answer 33

- 45X or 45X/46XX. | - short stature, ovary development is abortive, secondary sexual characteristics do not develop.

Question 34

What is 46XX DSD or 46XY DSD?

Answer 34

- external genitalia of one sex accompanies the other sex.

Question 35

Early exposure to androgens or excess amounts of androgens can result in what in females?

Answer 35

- 46, XX, DSD. | - clitoral hypertrophy and labial fold fusion.

Question 36

What are the characteristics of Androgen Insensitivity Syndrome?

Answer 36

- 46, XY, DSD. - will not respond to testosterone. - Will show female secondary sexual characteristics.

Question 37

What is 5 alpha reductase deficiency?

Answer 37

- genetic males that are born with ambiguous genitalia. | - Cannot convert testosterone into DHT.

Question 38

At what week does the phenotypic sexual differentiation begin?

Answer 38

Week 7.

Question 39

What cells releases AMH?

Answer 39

Sertoli cells in the testes

Question 40

What is the driving force for development of the male external genetalia?

Answer 40

DHT