development of both gonads

Question 1

urogenital system development arises from what?

Answer 1

the intermediate mesoderm
excretory ducts enter a common cavity (cloaca)

Question 2

what is the urogenital ridge?

Answer 2

gives rise to gonads - testes or ovaries
ductal system
PGC’s

Question 3

what is the cloaca?

Answer 3

gives rise to anal canal (posteriorlly)
and gives rise to urogenital sinus (anteriorly)

Question 4

where is cloaca in close relation to?

Answer 4

hindgut

Question 5

week 4-6 marks what journey of the PGC’s

Answer 5

• PGC’s within the yolk sac migrate via dorsal mesentery to intermediate mesoderm (genital ridges)

Question 6

coelomic epithelium profilerates and thickens to form what?-

Answer 6

genital ridges

Question 7

proliferating epithelium will form somatic support cells which envelop the PGCs and forms what?

Answer 7

primitive sex cords

Question 8

what are the 2 types of ducts the urogenital ridge gives rise to?

Answer 8

• wolffian duct (mesonephric duct)
• mullerian duct (paramesonephric duct)
• gubernaculum sits in between 2 structures

Question 9

male XY - changes occur where in gonads

Answer 9

• medulla

Question 10

female XX - changes occur where in gonads

Answer 10

cortex of gonads

Question 11

what is the Sry gene?

Answer 11

• expressed if on Y chromosome
• if expressed gives rise to TDF - testes determining factor which gives rise to testes

Question 12

Sry protein stimulates formation of what cell?

Answer 12

• sertoli cells which secrete MIF and stimulates gonadal ridge cells to form leydig cells to make testosterone

Question 13

testosterone being produced by leydig cells stimulate what duct to form what structures?

Answer 13

wolffian ducts to form epididymis, vas deferens, seminal vesicles

Question 14

if Sry negative what happens?

Answer 14

no TDF production therefore ovaries arise

Question 15

as there is no production of sertoli cells = no MIF which means what for female reproductive tract?

Answer 15

stimulation of mullerian ducts (paramesonephric ducts) which allows for development of fallopian tubes, uterus, upper 2/3 of vagina

Question 16

what is the gubernaculum?

Answer 16

guides descent of male or female reproductive system

Question 17

in the male what is the direction of travel of gonads?

Answer 17

abdominal cavity to scrotum
pull down testes, male ductal system and blood vessels to help with formation of spermatic cord

Question 18

in female what direction of travel of gonads?

Answer 18

guides ovaries/ductal system into pelvis
ligaments prevent its full descent through inguinal ring
- ovarian and round ligament assist here

Question 19

what hormone is involved in production of male external genitalia

Answer 19

dihydrotestosterone

Question 20

what hormone is involved in production of female external genitalia

Answer 20

oestrogen

Question 21

testes descend into scrotum when?

Answer 21

26 weeks and is complete around 35 weeks (8 months)

Question 22

before descent testis connect to what 2 structures?

Answer 22

• CSL - cranial suspensory ligament
• gubernaculum

Question 23

CSL?

Answer 23

• attaches the developing gonad to the posterior abdominal wall

Question 24

gubernaculum?

Answer 24

• ligament that attaches to inferior part of the testis to developing scrotum

Question 25

wolffian duct?

Answer 25

• forms epididymis and vas deferens

Question 26

mullerian duct?

Answer 26

regresses in males

Question 27

2 phases of testis descent?

Answer 27

transabdominal phase - week 7-8 (gubernaculum enlarges, testis moves closer to future inguinal canal)

inguinoscrotal phase - 25-35
(gubernaculum elongates towards the scrotum, testis follows and enters the scrotum)

Question 28

testis descent, what could go wrong?

Answer 28

congenital cryptorchism
inguinal hernia or hydrocele
acquired cryptorchidism