McCumbee - Sexual Differentiation

Question 1

Sex determination begins with a commitment of the indifferent gonads to become testes or ovaries. This process is _______ programmed

Answer 1

Genetically

Question 2

SRY region on a gene is the what?

Answer 2

Sex determining region

Question 3

During the 5th week of gestation, epithelial and underlying mesenchymal cells proliferate and form a thickened area called the ______ along the ventromedial surface of the mesonephros

Answer 3

Genital ridge

Question 4

Before the ______ week, gonads of both sexes are identical in appearance and are therefore referred to as indifferent gonads. At this stage, they are composed of an external cortex and an internal medulla

Answer 4

7th

Question 5

In males, precursor cells from the indifferent gonad differentiate into _____

Answer 5

Sertoli cells

Question 6

In XX embryo, indifferent gonad cells differentiate into _____ cells

Answer 6

Granulosa

Question 7

The outer cortex of the indifferent gonad is composed of

Answer 7

A thickened epithelial surface

Question 8

The inner medulla of the indifferent gonad is composed of ?

Answer 8

Primitive sex cords surrounded by mesenchymal tissue

Question 9

It is the sex chromosomes present in the ________ that will determine the type of gonad the genital ridge will become

Answer 9

Somatic cells of the genital ridge

Question 10

In the testis, the medulla _____ and the cortex ______

Answer 10

Differentiates

Regresses

Question 11

In the ovary, the cortex ______ and the medulla ________

Answer 11

Differentiates

Regresses

Question 12

The gene product of SRY is _____________

Answer 12

A transcription factor

Question 13

___________ is upregulated by SRY and is the principal regulator of Sertoli cell (males) differentiation

Answer 13

SOX9 gene product

Question 14

the first histologically discernable event of testes development is ?

Answer 14

The appearance of sertolic cells in the medulla of the indiferrent gonad

Question 15

Sertoli cells aggregate around the _____ to form testis cords

Answer 15

PGC’s

Question 16

___________ are the precursors of the seminiferous tubules

Answer 16

Testis cords

Question 17

The differentiation of an ovary from an indifferent gonad requires:

(X3)

Answer 17

Invasion of cortex by PGC’s

Reactivation of the inactivated x chromosome in the germ cells

The absence of the SRY gene

Question 18

Consists of a primary oocyte surround by a single layer of pregranulosa cells

These are then surrounded by a basal lamina

Answer 18

Primordial follicles

Question 19

The XX embryo is regulated by RSPO1 which is a direct activator of the ___________ pathway

Answer 19

WNT4/Beta-catenin

Question 20

Female developmental duct:

Answer 20

Mullerian (paramesonephric)

Question 21

Male developmental duct

Answer 21

Wolffian (mesonephric)

Question 22

If the Wolffian duct persists, it will differentiatie into:

X4

Answer 22

Epididymis

Seminal vesical

Vas deferens

Ejaculatory duct

Question 23

If the mullerian ducts persist, they will differentiate into: (x4)

Answer 23

Fallopian tubes

Uterus

Cervix

Upper 1/3 of the vagina

Question 24

Testosterone promotes differentiation of _______ ducts

Answer 24

Wolffian

Question 25

In males, AMH promotes the regression of ______ ducts

Answer 25

Mullerian

Question 26

What happens to wolffian ducts in the absence of hormone stimulation?

Answer 26

They will regress

Question 27

Regression of the mullerian ducts, which is induced by anti-mullerian hormone which is released by sertoli cells is time sensitive. This process begins around week _____ and the mullerian ducts lose sensitivity to AMH at week ____

Answer 27

7

8

Question 28

AMH (anti-mullerian hormone) induces apoptosis of mullerian ducts. This hormone is released from ____

Answer 28

Sertoli cells

Question 29

________ releases testosterone which allows the wolffian ducts to begin to differentiate around week 9

Answer 29

Leydig cells

Question 30

________ stimulates testosterone production by the fetal testes

Answer 30

Chorionic gonadotropin (hCG)

Question 31

Explain Syndrome of persistent Mullerian duct:

Answer 31

Phenotypic and genotypic male:

Lack of AMH synthesis or defective AMH receptor. Causes inability to degrade mullerian duct.
Differentiation of mullerian duct products occurs (fallopian tubes, uterus, cervix, upper 1/3 of vagina).
These will be present in hernias
Usually underdeveloped

Testes often fail to descend.

Question 32

Differentiation of the indifferent external genitalia (genital fold, genital tubercle, labioscrotal swelling) requires what ?

Answer 32

Dihydroxytestosterone (a potent enzyme derived from testosterone by 5alpha-reductase)

Question 33

The lower part of the vagina forms from the

Answer 33

Walls of the urogenital sinus

Question 34

The genital tubercle gives rise to the

Answer 34

Clitoris - females

Glans penis - males

Question 35

The genital swelling (labioscrotal swelling) gives rise to the

Answer 35

Scrotum - males

Labia majora - females

Question 36

The urethral folds form the ___

Answer 36

Ventral folds of the penis - males

Labia minora - females

Question 37

In males, what develops from the urogenital sinus?

Answer 37

The prostatic budds

Question 38

What is seen in complete androgen resistance?

Answer 38

Testes capable of secreting androgen are present in the abd cavity

Male and female internal genital tracts absent

External genitals and secondary sex characteristics are female

Scant or absent pubic hair

Question 39

What is seen in 5alpha-reductase deficiency.?

Answer 39

Unable to make external genital completely until puberty

Internal genitalia develops normally along male lines

External gentialia ambiguous due to incomplete masculinization.

Child often mistaken for female at birth

Question 40

What is the principle manifestation of androgen exposure after 12 weeks of gestation?

Answer 40

Clitoral hypertrophy