embryology - urinary and repro system development Flashcards
what forms the kidneys, ureter and gonads
intermediate mesoderm
what di the kidney and ureter develop from
urogenital ridge
how does the urogenital ridge form the kidney and ureter
differentiates into gonadal ridge
gives rise to gonad and nephrogenic cord laterally - this forms the kidney and ureter
where does the kidney develop
pelvis
ascends to abdomen by week 12
what does the cloaca give rise to
urogenital sinus which develops bladder and urethra and some parts of male/female reproductive tract
what is the nephrogenic cord
part of the urogenital ridge
what are the three stages of development of the nephrogenic cord
pronephros
mesonephros
metanephros - final kidney
where does the metanephros drain
nephritic duct then cloaca
what is the cloaca
caudal end of enfolded yolk sac
what is the cloacal membrane formed by
ectoderm and endoderm
what is the urorectal septum and what does it do
septum that divides cloaca into the urogenital sinus and anal canal
what does the urogenital sinus form
bladder and urethra
where do primordial germ cells originate
endoderm lining of yolk sac in hind gut at 6 weeks gestation
migrate to gonads
what forms the primitive sex cords
epithelium of gonadal ridge
what is the indifferent gonad
develops in gonadal ridge
made of a combination of germ cells and primitive sex cord cells
can develop into testes or ovaries
what are primitive sex cords
elongated projections that form from the gonadal ridge
how do ovaries develop
primitive sex cords extend into medulla then degenerate
seondary sex/cortical cords develop and surround ovaries to form primordial follicles
when is the ovarian reserve established
20 weeks gestation
what is the function of the SRY gene
produces SRY protein (testes determining factor) which promotes testes formation
how are the testes formed
primitive sex cords extend into medulla and form testis cords then seminiferous tubules and rete testes
how are sertoli cells formed
AMH causes them to be derived from surface epithelium
how are leydig cells formed and when do they produce testosterone
from intermediate mesoderm
produce testosterone from 8 weeks
where to the gonads originate
posterior abdominal wall
when do the testes reach the inguinal ring
by 7 months
what is cryptorchidism
undescended testicle
what is cryptorchidism
undescended testicle
what are the two sets of genital ducts
mesonephric duct - next to indifferent gonad
paramesonephric duct - lateral to mesonephric duct
what does AMH do
causes paramesonephric ducts to regress
mesonephric ducts from male repro organs
what is the trigone formed from in males and females
mesonephric ducts
how does the mesonephric duct persist in males
what does it form
AMH
testosterone
epididymis, vas deferens, seminal vesicles
what does the mesonephric duct form in males
epididymis
vas deferens
seminal vesicles
what happens to the mesonephric duct in females
regresses
what can the remnants of the mesonephric duct in females form
epoophoron
paraphoron
(small cystic structures)
gartners duct cyst
what do the paramesonephric ducts form in females
fuses and canalises to form uterus and upper 2/3 of vagina
unfused portions form fallopian tubes
what forms the lower 1/3 of the vagina
urogenital sinus
what forms the hymen
fusion of the paramesonephric ducts and urogenital sinus
where to urogenital folds form
either side of cloacal membrane
how is the genital tubercle formed
fusion of urogenital folds
what happens to the genital tubercle in males
elongates to form penis
wat happens to genital tubercle in females
forms labia minora and clitoris
what happens to the labioscrotal swelling and urogenital folds in males
labioscrotal swelling folds fuse posteriorly
urogenital folds fuse posteriorly to form penile urethra
what happens to the labioscrotal folds in females
form labia majora
