Urogenital Embryo

Question 1

Where do primordial germ cells originate? What germ layer do they end up in?

Answer 1

Epiblast (yolk sac specifically)- end up in endodermal cells

Question 2

What type of tumor results from an abnormal migration of primordial germ cells?

Answer 2

Extragonadal germ cell tumor

Question 3

What are the genital ridges a proliferation of?

Answer 3

Coelomic epithelium - forms germinal epithelium, outermost layer of male and female gonads

Question 4

Migration of what induces development of the gonad into ovary or testis?

Answer 4

Primordial germ cells invading genital ridges

Question 5

What is the source of ovarian cancer and endometriosus?

Answer 5

Coelomic epithelium

Question 6

What gene on the Y chromosome determines if testis will develop?

Answer 6

SRY

Question 7

What protein does the SRY gene produce?

Answer 7

TDF - testis-determining factor

Question 8

What are the three cell types present in the testis cords?

Answer 8

Primitive germ cells, Sertoli (sustentacular) cells, Leydig (interstitial) cells

Question 9

When do testis cords acquire a lumen and become seminiferous tubules?

Answer 9

Puberty

Question 10

What is the embryological origin of the vas deferens?

Answer 10

Mesonephric duct

Question 11

What type of cords proliferate in the female?

Answer 11

Cortex/cortical (secondary) cords

Question 12

What type of cords proliferate in the male?

Answer 12

Medullary (primitive sex) cords

Question 13

What do the cortical cords in the female transform into?

Answer 13

Follicular cells

Question 14

What genes does TDF induce downstream?

Answer 14

Mullerian inhibitory substance (MIS), testosterone

Question 15

What type of cells produce Mullerian inhibitory substance (MIS)? What does it do?

Answer 15

Sertoli cells - causes regression of paramesonephric ducts

Question 16

What type of cells produce testosterone? What does it do?

Answer 16

Interstitial cells of Leydig - mediates virilization of mesonephric duct

Question 17

What does testosterone get converted into? What does it do? What enzyme does this?

Answer 17

dihydrotestosterone (DHT) - acts on external genitalia

5a reductase

Question 18

What would you see clinically if someone has issues making DHT but not testosterone?

Answer 18

Female genitalia but internal testosterone influence

Question 19

What is the name of the genital duct in males?

Answer 19

Wolffian/Mesonephric

Question 20

What is the name of the female genital duct?

Answer 20

Mullerian/Paramesonephric duct

Question 21

What are the remnants of the Mullerian duct in males called?

Answer 21

Utriculus prostaticus

Question 22

What are the remnants of the Wolffian duct called in females?

Answer 22

Epoophoron, paraoophoron, Gartner’s cyst

Question 23

What clinical correlation is remnants of the paramesonephros?

Answer 23

Paraovarian cysts

Question 24

What results from an imperforate hymen?

Answer 24

Metrocolpus - uterus fills w/ menstrual fluid b/c there is nowhere to go

Question 25

What types of cells form the external genitalia around the cloacal membrane?

Answer 25

Mesenchymal cells

Question 26

What syndrome does XXY result in?

Answer 26

Klinefelter's

Question 27

What syndrome does a single X result in?

Answer 27

Turner's

Question 28

What is female pseudohermaphroditism?

Answer 28

Biochemical defect in steroid production - you make a lot of sex steroids, so this personw ould have uterus and ovaries but ambiguous genitalia

Question 29

What is male pseudohermaphroditism?

Answer 29

Caused by decrease in androgenic hormones - tissues do not respond to DHT, so there are testes, but also a short blind vagina

Question 30

What is hypospadias? Epispadias?

Answer 30

When urethral groove doesn't close completely inferiorly | When urethral groove doesn't close completely superiorly

Question 31

How do uterine anomalies result?

Answer 31

When Mullerian ducts don't connect with each other correctly

Question 32

In the female, what forms from the urogenital sinus?

Answer 32

Urinary bladder, urethra, lower vagina, vestibule, greater vestibular/urethral glands

Question 33

In the male, what forms from the urogenital sinus?

Answer 33

Urinary bladder, urethra, prostate gland, bulbourethral/Cowpers glands

Question 34

In the female, what forms from the mesonephric duct and tubules?

Answer 34

Ureter, renal pelvis, major and minor calices, collecting tubules

Question 35

In the male, what forms from the mesonephric duct and tubules?

Answer 35

Efferent ductules, duct of epididymis, ductus deferens, ejaculatory duct, seminal vesicles, ureter, renal pelvis, calices, collecting tubules

Question 36

In the female, what forms from the paramesonephric duct?

Answer 36

Uterine tubes, uterus, upper vagina

Question 37

In the male, what forms from the paramesonephric duct?

Answer 37

Vestigial - appendix of testis

Question 38

In the female, what forms from the genital tubercle/phallus?

Answer 38

Clitoris (glans, corpora cavernosa, bulb of vestibule)

Question 39

In the male, what forms from the genital tubercle/phallus?

Answer 39

Penis (glans, corpora cavernosum, corpus spongiosum)

Question 40

In the female, what forms from the urogenital folds?

Answer 40

Labia minora, perineal raphe, perianal tissue and external anal sphincter

Question 41

In the male, what forms from the urogenital folds?

Answer 41

Ventral aspect of penis, most of penile urethra, perineal raphe, perianal tissue and external sphincter

Question 42

In the female, what forms from the labioscrotal folds?

Answer 42

Labia majora

Question 43

In the male, what forms from the labioscrotal folds?

Answer 43

Scrotum

Question 44

In the female, what forms from the indifferent gonad?

Answer 44

Ovary - follicles from secondary sex cords in cortex

Question 45

In the male, what forms from the indifferent gonad?

Answer 45

Testis - seminiferous tubules from primary sex cords, rete testis in medulla

Question 46

In the female, what forms from the gubernaculum?

Answer 46

Ovarian ligament and round ligament of the uterus

Question 47

In the male, what forms from the gubernaculum?

Answer 47

Gubernaculum testis