Male Repro Embryology

Question 1

What happens when mesonephric tubules get testosterone?

Answer 1

They proliferate and form connections with the sex cords to form a continuous duct system.

Question 2

What’s the ejaculatory duct?

Answer 2

It’s after the seminal duct has joined with the vas deferens.

Question 3

5 structures that the mesonephric tubules give rise to?

Answer 3

1) Efferent ductules
2) Ductus epididymus
3) Ductus deferens
4) Seminal gland/vesicle
5) Ejaculatory duct
(pretty intuitive - they’re all continuous)

Question 4

Review: From whence is the epithelium of the bladder and urethra?

Answer 4

Endoderm.

Question 5

Where does the prostate and bulburethral gland come from? What does their proper differentiation depend upon?

Answer 5

Endoderm.

Differentiation depends on DHT (NOT testosterone= key point)

Question 6

What does the differentiation of external genitalia depend upon?

Answer 6

DHT

Question 7

What enzyme converts testosterone to DHT?

Answer 7

An alpha reductase.

Question 8

Where is the bulburethral gland?

Answer 8

Downstream of the prostate, in among the urogenital diaphragm.

Question 9

What do the urogenital folds do in males?

Answer 9

They fuse, becoming the shaft / “raphe”/ ventral aspect of the penis.

Question 10

What is the scrotum formed from?

Answer 10

Labialscrotal folds.

Question 11

What is the processus vaginalis? Why is it bad if the processus vaginalis doesn’t obliterate?

Answer 11

Is a double layer of peritoneum that provides a friction free path of descent for the testes

One is highly predisposed to indirect hernia.

Question 12

What cells drive spermatogenesis to start up at puberty?

Answer 12

A new population of Leydig cells (testosterone produced also has other effects)

Produce millions of sperm for 40 years

Question 13

Are males or females more likely to have abnormalities in sexual development?

Answer 13

Males - there’s more to mess up.

Question 14

What are 3 things will be underdeveloped if a male lacks the reductase that converts testosterone to DHT?

Answer 14

1) External genitalia
2) Bulburethral glands
3) Prostate.

Question 15

What happens if a XY person has no working androgen receptor? How does it commonly present?

Answer 15

Male external and internal genitalia fail to develop.
Female-appearing person presents with bilateral indirect hernia - which turn out to be testes trying to descend into the labia majora.

Question 16

What are the 3 major roles of Sertoli Cells in male gonadal development during embryogenesis?

Answer 16

1) Block gametogenesis
2) Produce AMH–> suppress Mullerian/Paramesonephric ducts (makes them degenerate)
3) Induce formation of Leydig cells (which make testosterone)

Question 17

What is the skeletal muscle of urinary continence in both men and women?

Answer 17

Urogenital diaphragm with sphincter urethrae