Sex Determination

Question 1

Where do gonads develop?

Answer 1

Trunk of body (halfway between shoulder and pelvis)

Question 2

Where does the germ line come from?

Answer 2

Epiblast cells not included in gastrulation

Question 3

Where do germ line cells migrate to?

Answer 3

Gut, then mesentry, to gonadal ridge

Question 4

Mesentry

Answer 4

Sheet of tissue connecting gut to cavity wall

Question 5

Androgenic hormones

Answer 5

Testosterone and anti- mullerian hormone (AMH destroys early oviducts and uterus)

Question 6

What cell produces testosterone and what does it do?

Answer 6

Leydig cells, forces wolffian ducts to survive which go on to become vas deferens

It stimulates androgen receptor weakly

Question 7

What is 5a-reductase

Answer 7

Enzyme that converts testosterone to 5a-dihyrotestosterone which stimulates androgen receptors strongly

Question 8

Guevedoces

Answer 8

When XY children have 5a-reductase deficiency, female bodies before puberty but make after (as testosterone levels high enough to stimulate androgen receptors without enzyme)