Genital System Development

Question 1

What is the difference between gender genotype and phenotype?

Answer 1

geno is the inherited genes that determine gonad

pheno is hormones released during development

Question 2

What is the indifferent stage?

Answer 2

transitional stage of development where gonads, genital ducts and external features are the same in both sexes

Question 3

What germ layer makes up the gonadal ridge?

Answer 3

intermediate mesoderm and coelomic mesothelium

Question 4

Where is the gonadal ridge located?

Answer 4

medial to the nephrogenic cord

Question 5

What cell types make up the gonad?

Answer 5

germ cells and supporting cells

Question 6

What do supporting cells arise from?

Answer 6

invading mesothelium and disintegrating mesonephric tubules

Question 7

What do germ cells arise from?

Answer 7

yolk sac endoderm

Question 8

How do germ cells reach the gonadal ridge?

Answer 8

they migrate along the gut wall and mesentery

Question 9

What do supporting cells form within the gonad?

Answer 9

cellular cords (gonadal cords) that radiate into gonadal ridge

Question 10

Where must germ cells migrate and what happens if they don’t?

Answer 10

inside gonadal cords surrounded by supporting cells, they will be degenerated if they don’t

Question 11

What do gonadal cords become in the testis?

Answer 11

seminiferous cords

Question 12

What happens to germ cells within seminiferous cords?

Answer 12

they become dormant spermatagonia

Question 13

What happens to seminiferous cords and spermatagonia at puberty?

Answer 13

The cords are canalized and become seminiferous tubules and the spermatogonia begin spermatogenesis

Question 14

What are sustentacular cells?

Answer 14

secrete inhibitory factors in wall of seminiferous tubules

suppress spermatogenesis and female duct development (paramesonephric duct)

Question 15

What are interstitial cells?

Answer 15

outside seminiferous tubules

some produce androgen right away and some wait until sexual maturity

Question 16

What does androgen do?

Answer 16

stimulate male genital development

Question 17

What happens to gonadal cords in the ovary?

Answer 17

they become primordial follicles that surround individual germ cells

Question 18

What happens to germ cells within primordial follicles?

Answer 18

they become oogonia and differentiate into primary oocytes that start meiosis but get stuck in prophase of meiosis 1 (lifetime allotment)

Question 19

At the indifferent stage both sexes have what?

Answer 19

male mesonephric and female paramesonephric genital ducts and a urogenital sinus

Question 20

describe paramesonephric duct development

Answer 20

develops on ventrolateral coelomic surface of mesonephros, begins as a groove that eventually elongates and canalizes

Question 21

What determines which duct system will develop from the indifferent stage?

Answer 21

testicular hormones

interstitial cells produce testosterone for male and suppress female with sustentacular inhibition

Question 22

What happens to duct development if there’s no testosterone?

Answer 22

the mesonephric duct (future epididymis) fails to form

Question 23

What does the paramesnephric duct become in females?

Answer 23

cranial becomes uterine tube

caudal becomes uterine horn

Question 24

What do the fused ends of the paramesonephric ducts become?

Answer 24

uterine body, cervix, cranial vagina (in contact with urogenital sinus)

Question 25

What is the vaginal plate?

Answer 25

a solid outgrowth of the urogenital sinus that later develops a lumen to become the caudal vagina it is the point of attachment of the paramesonephric ducts

Question 26

What are efferent dutules in the testis?

Answer 26

mesonephric tubules that persist and communicate between the epididymis and the testes

Question 27

How do the prostate and bulbourethral glands form?

Answer 27

outgrowth of urogenital sinus endoderm

Question 28

What is the gubernaculum and it's function in the male?

Answer 28

a condensation of mesenchyme that becomes a gel mass, passively pulls testis to inguinal canal and intra abdominal pressure can pop the testis into the scrotum

Question 29

When the mesonephros degenerates what does it leave behind?

Answer 29

a genital fold that suspeds the gonad and genitla ducts

Question 30

What does the genital fold become in females?

Answer 30

the broad ligament (suspensory of ovary, mesovarium, mesosalpinx, mesometrium)

Question 31

What does the inguinal fold become in females?

Answer 31

proper ligament of ovary and round ligament of uterus

Question 32

What does the genital fold become in males?

Answer 32

mesorchium and mesoductus deferns

Question 33

What does the inguinal fold become in males?

Answer 33

gubernaculum, proper ligament of testis and ligament of tail of epididymis

Question 34

What are the 3 perineal swellings of the indifferent stage?

Answer 34

urogenital folds, ventral genital tubercle, bilateral genital swellings

Question 35

What does the genital tubercle become in the male?

Answer 35

the elongate phallus and the glans at the tip

Question 36

What do the urogenital folds become in the male?

Answer 36

they elongate and close to form the penile urethra

Question 37

What does the genital tubercle mesenchyme give rise to in males?

Answer 37

erectile tissue, tunica albuginea, smooth muscle, and bone

Question 38

What do the genital swellings become in the male?

Answer 38

they merge to form the scrotum with two compartments

Question 39

How is the prepuce formed?

Answer 39

a ring of surface ectoderm invades mesenchyme at the free end of the phallus

Question 40

What does the urogenital orifice become in females?

Answer 40

the vulval cleft entering the vestibule

Question 41

What does the genital tubercle become in females?

Answer 41

the clitoris

Question 42

What do the urogenital folds become in the female?

Answer 42

labia of the vulva

Question 43

What happens to the genital swellings in the female?

Answer 43

disappear in domestic mammals

Question 44

Describe mammary development

Answer 44

mammary ridge, mammary buds, mammary glands

Question 45

What happens to the induced epithelium of a mammary bud?

Answer 45

epithelial solid cords invade mesoderm and form epithelial lined lactiferous ducts