EX3 Embryology - Genital System

Question 1

What germ layer is the genital system derived from

Answer 1

intermediate mesoderm

Question 2

Intermediate mesoderm thickens at week 5 to form what precursor to the genital system

Answer 2

gonadal ridge

Question 3

At what week do the visible differences of the genital system show

Answer 3

week 7

weeks 1-6 are the “indifferent stage”

Question 4

The sex of an individual is determined at what stage

Answer 4

conception

Question 5

What are the two ducts that are precursors to the male/female gonads

Answer 5

males - mesonephric (Wolffian) duct

females - paramesonephric (Müllerian) duct

Question 6

The mesothelium lining of each gonadal ridge thickens to form what

Answer 6

mesothelial cells = gonadal cord cells

Question 7

The mesothelial cord cells form what

Answer 7

solid gonadal cords that sink into underlying mesenchyme to “welcome” PGCs

Question 8

SRY codes for what

Answer 8

TDF; testes-determing factor

Question 9

These develop from mesenchyme of gonadal ridge and produces testosterone

Answer 9

leydig cells

Question 10

These develop from gonadal cord cells and forms the seminiferous tubules and rete testes

Answer 10

sertoli cells (“caretakers of PCGs”)

Question 11

How are seminiferous tubules formed

Answer 11

by an invagination of cord cells

Question 12

What induces the mesonephric duct to form male genital ducts and external genitalia

Answer 12

testosterone

Question 13

Testosterone causes the mesonephric ducts and mesonephric tubules to do what

Answer 13

puncture the region of the gonadal ridge where testicles are developing to form the ductus deferens, epididymis, and efferent ductules connections

Question 14

The mesonephric duct becomes what in males

Answer 14

ductus deferens

Question 15

The superior end of the mesonephric duct becomes what in males

Answer 15

epididymis

Question 16

The mesonephric tubules become what in males

Answer 16

efferent tubules

Question 17

The caudal ends of mesonephric ducts develop what

Answer 17

seminal vesicles and ejaculatory ducts which open into prostatic urethra

Question 18

The Müllerian duct reman at becomes what in males

Answer 18

appendix testis

Question 19

The Müllerian duct regresses in males due to which cell signalsing

Answer 19

Sertoli cells; produces MIH (Müllerian-inhibiting hormone)

Question 20

The prostate and bulbourethral glands are endodermal outgrowth from what

Answer 20

urogenital sinus

Question 21

This extends from the gonad to the labioscrotal swelling

Answer 21

gubernaculum

Question 22

The descent of the testes begins in which weeks and ends when

Answer 22

begins week 26; both testes in scrotum by week 32

Question 23

What is the gubernaculum

Answer 23

it is a ligament that as it shortens, it pulls the testis, ductus deferens, and testicular vessels downward traversing the inguinal canal to the scrotal sac

Question 24

Where are the layers of the spermatic cord derived from

Answer 24

anterior abdominal wall muscular layers/fascia that are dragged inferiorly with the testes

Question 25

This is the development of fluid-filled cysts of the testes/spermatic cord

Answer 25

hydrocoele

Question 26

This is the failure of the testes to descend

Answer 26

crytochidism

Question 27

True or False | The female genital system contains SRY and TDF

Answer 27

False; it does not

Question 28

Where do the stromal cells of the developing ovary originate from

Answer 28

mesenchyme of gonadal ridge

Question 29

Follicular cells ("caretakers" of the PGCs" develop from what

Answer 29

gonadal cord cells

Question 30

These envelop PGCs

Answer 30

cortical cords (comprised of cord cells)

Question 31

Cortical cords break up into pieces, and cord cells develop into what

Answer 31

flat follicular cells that surround each oogonium

Question 32

The primary oocyte plus the follicle cell capsule makes up what

Answer 32

primordial follicle

Question 33

Due to low testosterone in females, what happens

Answer 33

mesonephric ducts regress

Question 34

Due to no MIH in females, what happens

Answer 34

continued grout and development of Müllerian ducts

Question 35

Epoöphoron, paraöphoron, and gartner duct cysts are what in females

Answer 35

remnants of mesonephric duct

Question 36

The cranial end of the Müllerian ducts form what

Answer 36

uterine tubes

Question 37

The caudal end of the Müllerian ducts fuse to form what

Answer 37

uterovaginal primordium; which forms the uterus and superior vaginal canal

Question 38

The uretovaginal primordium comes in contact with dorsal wall or urogenial sinus and induces the formation of what

Answer 38

sinovaginal bulbs; pair of endodermal outgrowths

Question 39

The sinovaginal bulbs fuse with the uretovaginal primordium forming what

Answer 39

the vaginal plate (inferior vagina) | *formed from urogenital sinus*

Question 40

The vaginal canal forms from what

Answer 40

the degeneration of the vaginal plate central endodermal cells

Question 41

What are the endodermal outgrowths from the urogenital sinus

Answer 41

greater vestibular glands urethral glands paraurethral glands

Question 42

The gubernaculum in females forms what

Answer 42

the ovarian and round ligament

Question 43

The genital tubercle forms what in males/females

Answer 43

males - glans penis (head) | females - clitoris

Question 44

The labioscrotal swelling (genital swelling) forms what in males/females

Answer 44

males - scrotum | females - labium majus

Question 45

The urethral folds form what in males/females

Answer 45

males - penile shaft | females - labium minus