Cloaca, uterus, external genitalia

Question 1

What is the SDR of the Chromosome?

Answer 1

SDR = sex determining region - which makes the testis determining factor - this acts on the indifferent gonad -

Question 2

What does the testis determining factor do?

Answer 2

acts on the indifferent gonad - which originally looks the exact same until given a signal by the SDR

influences development of the

testis

medullary cords

no cortical cords

and thick tunica albuginea

Question 3

If there is no influence of the SDR, what occurs?

Answer 3

ovaries develop

medullary cords degenerate

cortical cords devellop

no tunica albuginea

Question 4

From what embryological structure do the gonads develop?

Answer 4

from the genital ridge

Question 5

What migrates into the genital ridge?

Answer 5

the primordial germ cells

Question 6

the mesonephros is what kidney?

Answer 6

the intermediate kidney

Question 7

waht is the purpose of the paramesonephric duct?

Answer 7

it is the precursor of the peritoneum

Question 8

what layer overlies the genital ridge?

Answer 8

the proliferating epithelium

Question 9

where do the germ cells lie in the early embryo?

Answer 9

they immigrate into the genital ridge and sit withiin the primative sex cords

Question 10

the mesonephros is what level of kidney?

Answer 10

it is the final kidney

Question 11

what cells indicate the development of testosterone in males?

Answer 11

The Leydig Cells -

Question 12

What cells tell the paramesonephric ducts to degenerate in the male?

Answer 12

sertoli cells- which secrete the mullerian inhibiting substance

Question 13

The testis determining factor tell the primitive sex cords to do what?

Answer 13

it tells them to persist - become the testis cords - they line up nicely in a row and then develop the rete testis cords which develop towards the mesonephric tubule -

then it becomes more organized to become little horsewhoe shaped testis cords which are still attached to the excretory mesonephric tubules -

Question 14

What embryological strucutre becomes the Vas Deferens?

Answer 14

the mesonephric duct

Question 15

what occurs to the excretory mesonephric tubules in men?

Answer 15

it degrades over time

Question 16

the ureteric bud in men develops off of what strucutre?

Answer 16

it buds off of the mesonephric duct - to become the ureter

Question 17

Why does the trigone look different from the rest of the detrusor muscle?

Answer 17

because the trigone comes from the mesonephric duct embryologically - where as the detruser comes from the bladder development seperately

Question 18

what ligament brings the testis posterior?

Answer 18

the gubernaculum = mesodermal tissue - goes from the lower pole of gonate to the inguinal ring

Question 19

The processes vaginalis is continueous with what strucutre?

Answer 19

it is continuous with the peritoneum

Question 20

What occurs if the peritoneum and the tunica vaginalis fail to dissociate?

Answer 20

Potential indirect inguinal hernia

Question 21

What is the term for peritoneum closing off from both the tunnica vaginallis and the peritoneum?

Answer 21

Hydrocoele - could potentially start to secrete fluid

Question 22

What is the term for ‘undescended’ testis? What is the risk of it?

Answer 22

Cryptorchidism - could potentially lead to testicular carcinoma- easy to cure if caught early.

You require surgery to bring the testi down

Question 23

What is the term when the testi has a deviant migration?

Answer 23

maldescended or ‘ectopic testis’

abnormal location

Question 24

What occurs to the primitive sex cords in women?

Answer 24

they degenerate - and instead the secondary cortical cords develop -

Question 25

what occurs to the germ cells in women?

Answer 25

they are surrounded by folliculum and stored = folliceles

Question 26

what occurs to the mesonephric duct and tubules in women?

Answer 26

they begin to vanish away - the paramesonephric duct becomes more important

Question 27

What does the paramesonephric duct become?

Answer 27

it becomes the uterus and fillopian tubes

Question 28

the remnant of the gubernaculum in women is what strucuture?

Answer 28

the round ligament

Question 29

what is a bicornis uterus?

Answer 29

where the septum between the two mesonephric ducts never really closes

Question 30

what is the term for a double vagina?

Answer 30

uterus didelphys

Question 32

what is the term for one mesonephric duct never combining with the other?

Answer 32

you get a rudimentary horn on one side of the uterus - only one connective fillopian tube

Question 33

The cloaca is a common.. ?

Answer 33

common excretory duct - between the bladder and anus

Question 34

what divides the anus from the urethra in the embryo?

Answer 34

the urogenital sinus

Question 35

how can you tell the difference between boy and girl at this stage of development?

Answer 35

the two folds combine at the back to form the scrotum in picture A

Question 36

where is the squamo columnar junction occur in the vagina?

Answer 36

the squamocolumnar junction is at the opening of the cervix- not at the embryological junction of tissues oddly enough

Question 37

What is haematocolpos?

Answer 37

where the hymen never breaks open - no menstrual product is allowed to leak, therefore they are retained - very painful

Question 38

what is a urorectal fistula?

Answer 38

where the urethra and the rectum are still connected - note there is still a 'dip' in the outer epithelium wehre it 'should' be

Question 39

what is a rectovaginal fistula?

Answer 39

where the rectum and the vagina are still connected

Question 40

what is the effect of testosterone on development?

Answer 40

the mesonephric ducts stimulated (vas deferens, epididymis)

Question 41

what is dihydrotestosterone? Why is it important?

Answer 41

it is the reduced forme of testosterone - it is the main driver of the external genitalia to take on male like characteristics - stimulates growth of penis, scrotum and prostate

Question 42

describe the developlement of the penis

Answer 42

most of the penile urethra is simply formed by the two urethral folds coming together on the mid line and closing the urethral in =

Question 43

What sort of epithelium lines the very distal part of the male urethra?

Answer 43

stratified squamus b/c the epithelial invaginates the end of the penis - it is not from the urehtral development which is mainly transitional epithelium

Question 44

what is hypospadias?

Answer 44

when the two urethral folds do not close properly along the midline - you're left with a small opening in the base of the penis - how distal or proximal it is... depends on the functionality of it - if it's distal, not a big deal doesn't effect functionality - if it is perineal, then it should probably be corrected surgicaly -

Question 45

what is epispadias?

Answer 45

when you have an opening on the dorsal surface of the penis - here the genital tubercle is not in it's proper position in the urogential membrane - so you have the urthral fold and urogenital membrane anteiror to it- you don't get an anterior wall to the bladder,

Question 46

the labia majus develops from what embryological structure?

Answer 46

develops from the genital swelling

Question 47

what is pseudohermaphroditism?

Answer 47

virilization of the external genitalia - of the female to look more like a male due to excessive androgens

Question 48

what is Male pseudomaphroditism?

Answer 48

a man who has reduced androgen production or androgen insensitivity during development leading to no virulization of the external genitalia- and female gentialia to develop