Cloaca, uterus, external genitalia Flashcards
What is the SDR of the Chromosome?
SDR = sex determining region - which makes the testis determining factor - this acts on the indifferent gonad -
What does the testis determining factor do?
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
If there is no influence of the SDR, what occurs?
ovaries develop
medullary cords degenerate
cortical cords devellop
no tunica albuginea
From what embryological structure do the gonads develop?
from the genital ridge
What migrates into the genital ridge?
the primordial germ cells
the mesonephros is what kidney?
the intermediate kidney
waht is the purpose of the paramesonephric duct?
it is the precursor of the peritoneum
what layer overlies the genital ridge?
the proliferating epithelium
where do the germ cells lie in the early embryo?
they immigrate into the genital ridge and sit withiin the primative sex cords
the mesonephros is what level of kidney?
it is the final kidney
what cells indicate the development of testosterone in males?
The Leydig Cells -
What cells tell the paramesonephric ducts to degenerate in the male?
sertoli cells- which secrete the mullerian inhibiting substance
The testis determining factor tell the primitive sex cords to do what?
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 -
What embryological strucutre becomes the Vas Deferens?
the mesonephric duct
what occurs to the excretory mesonephric tubules in men?
it degrades over time
the ureteric bud in men develops off of what strucutre?
it buds off of the mesonephric duct - to become the ureter
Why does the trigone look different from the rest of the detrusor muscle?
because the trigone comes from the mesonephric duct embryologically - where as the detruser comes from the bladder development seperately
what ligament brings the testis posterior?
the gubernaculum = mesodermal tissue - goes from the lower pole of gonate to the inguinal ring
The processes vaginalis is continueous with what strucutre?
it is continuous with the peritoneum
What occurs if the peritoneum and the tunica vaginalis fail to dissociate?
Potential indirect inguinal hernia
What is the term for peritoneum closing off from both the tunnica vaginallis and the peritoneum?
Hydrocoele - could potentially start to secrete fluid
What is the term for ‘undescended’ testis? What is the risk of it?
Cryptorchidism - could potentially lead to testicular carcinoma- easy to cure if caught early.
You require surgery to bring the testi down
What is the term when the testi has a deviant migration?
maldescended or ‘ectopic testis’
abnormal location
What occurs to the primitive sex cords in women?
they degenerate - and instead the secondary cortical cords develop -
what occurs to the germ cells in women?
they are surrounded by folliculum and stored = folliceles
what occurs to the mesonephric duct and tubules in women?
they begin to vanish away - the paramesonephric duct becomes more important
What does the paramesonephric duct become?
it becomes the uterus and fillopian tubes
the remnant of the gubernaculum in women is what strucuture?
the round ligament
what is a bicornis uterus?
where the septum between the two mesonephric ducts never really closes
what is the term for a double vagina?
uterus didelphys
what is the term for one mesonephric duct never combining with the other?
you get a rudimentary horn on one side of the uterus - only one connective fillopian tube
The cloaca is a common.. ?
common excretory duct - between the bladder and anus
what divides the anus from the urethra in the embryo?
the urogenital sinus
how can you tell the difference between boy and girl at this stage of development?
the two folds combine at the back to form the scrotum in picture A
where is the squamo columnar junction occur in the vagina?
the squamocolumnar junction is at the opening of the cervix- not at the embryological junction of tissues oddly enough
What is haematocolpos?
where the hymen never breaks open - no menstrual product is allowed to leak, therefore they are retained - very painful
what is a urorectal fistula?
where the urethra and the rectum are still connected - note there is still a ‘dip’ in the outer epithelium wehre it ‘should’ be
what is a rectovaginal fistula?
where the rectum and the vagina are still connected
what is the effect of testosterone on development?
the mesonephric ducts stimulated (vas deferens, epididymis)
what is dihydrotestosterone? Why is it important?
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
describe the developlement of the penis
most of the penile urethra is simply formed by the two urethral folds coming together on the mid line and closing the urethral in
=
What sort of epithelium lines the very distal part of the male urethra?
stratified squamus b/c the epithelial invaginates the end of the penis - it is not from the urehtral development which is mainly transitional epithelium
what is hypospadias?
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 -
what is epispadias?
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,
the labia majus develops from what embryological structure?
develops from the genital swelling
what is pseudohermaphroditism?
virilization of the external genitalia - of the female to look more like a male due to excessive androgens
what is Male pseudomaphroditism?
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
