Male Embryogenesis

Question 1

Testes differentiation factor (TDF)

Answer 1

Protein that stimulates development of testes

Question 2

Leydig/Sertoli cells

Answer 2

Produce testosterone and anti-mullerian hormone (AMH) which causes paramesonephric ducts to regress

Question 3

Mesonephric Ducts

Answer 3

develops into epididymis and ductus deferens

Question 4

Mesonephric tubules

Answer 4

develop into efferent ducts

Question 5

Primitive sex cords

Answer 5

develop into seminiferous tubules

Question 6

Undeveloped testes

Answer 6

primitive sex cords → rete testis → mesonephric tubules → mesonephric ducts

Question 7

Developed testes

Answer 7

sperm in seminiferous tubules → rete testis → efferent ducts → ductus deferens

Question 8

Developmental sequence of embyronic testes

Answer 8

1. Primitive sex cords align themselves with rete testis tubules, mesonephric tubules not yet connected
2. Sex cords connect to rete tubules which connect to mesonephric tubules, paramesonephric duct starts degenerating
   Sex cords are now epithelial cords
3. Epithelial cords become seminiferous tubules, there is continuity of vessels throughout system and mesonephric ducts and tubules have developed

Question 9

Spermatogonial stem cells (SSC)

Answer 9

spermatogonium that does not develop into a spermatocyte and instead divides again into more spermatogonia to produce more spermatocytes

Question 10

What happens to the testes upon puberty?

Answer 10

they descend from retroperitoneal position to their final position outside of body cavity and within scrotum

Question 11

transabdominal phase

Answer 11

distal (caudal) end of gubernaculum fuses with peritoneum at inguinal ring and testes move from retroperitoneal position to inguinal canal

Question 12

Visceral vaginal tunic

Answer 12

dorsal layer of peritoneum that descends with testes into abdominal cavity during transabdominal phase

Question 13

Inguinal-scrotal phase

Answer 13

gubernaculum grows rapidly in width (not length) which forces testes through inguinal ring into scrotum

-gubernaculum then regresses and pulls testes deeper into scrotum to cause full encapsulation by visceral vaginal tunic

Question 14

Parietal vaginal tunic

Answer 14

second, ventral layer of peritoneum that descends with testes into scrotum; is directly upon visceral vaginal tunic (within scrotum) and is continuous with rest of peritoneum

Question 15

Inguinal herniation

Answer 15

loop of intestines descends into vaginal cavity (btwn visceral and parietal) and becomes trapped by inguinal ring due to inflammation

Question 16

Cryptorchidism

Answer 16

failure of testes to descend, animals with unilateral failure of descendent can still be fertile but bilateral failure causes sterility; both kinds still produce testosterone