Embryology of Genital Tracts Flashcards
Why is the inital stage of genital development referred to as the indifferent stage of genital devleopment?
early genital systems of the two sexes are similar
When does gondal development begin?
week 5
What is the gonadal ridge?
a bulge of proliferating mesonephros
Where do the primordial germ cells originate?
wall of the umbilical vesicle (yolk sac) from the epiblast
How do the primordial germ cells reach the gonadal ridges?
migrate along the mesentery of the hindgut
What happens to the primordial germ cells in the 6th week?
primordial cells enter the underlying mesenchyme and are incorporated into the gonadal cords
What type of substance is mullerian-inhibiting factor?
glycoprotein
What tissue forms the urinary and reproductive systemms?
intermediate mesoderm
What effect does the arrival of the primordial germ cells have on the mesonephros?
stimulates proliferation to form the genital ridge
What is the difference between the medullary and cortical cord development in presence with and without SRY?
with SRY, medullary cords develop whereas in ovary cortical cords develop and medullary degenerate
What forms the medullary gonadal cords?
mesonephric tubule
What forms the cortical cords?
surface epithelium of the gonad
What are the paramesonephric ducts also known as?
Mullerian duct
Which cells secrete mullerian inhibiting substance?
sertoli cells
What other name is given to the mesonephric tubule?
Wolffian ducts
What parts of the male genital system does the mesonephric ducts give rise to?
efferent ductules; epididymis; vas deferens and seminal vesicles
How does the epididymis form?
mesonephric ducts near testis will become highly coiled
What is the tunica vaginalis?
peritoneum anterior to testis in scrotum
What is the function of the gubernaculum testis?
anchors the testis to scrotum
What tissue forms the internal spermatic fascia?
transversalis fascia
What tissue forms the cremasteric fascia?
internal oblique
What tissue forms the external spermatic fascia?
external oblique
What do the cortical cords embedded in primordial germ cells go on to form?
separate to become primordial follicles
What happens to the distal ends of the paramesonephric ducts?
meet in the midline to form the uterine canal and join to the wall of the urogenital sinus
What happens when the paramesonephric ducts join to the wall of the urogenital sinus?
causes area of wall to proliferate creating hte sinovaginal bulb
What do the sinovaginal bulbs proliferate to form?
the vaginal plate
What is the difference between the origins of the upper and lower vagina/
upper third- paramesonephric ducts; lower 2/3rds- proliferation of endoderm of urogenitla sinus
What is the ligament of the ovary proper formed from?
gubernaculum- attaches from ovary to uterus (where gubernaculum attaches to paramesonrphric duct)
What does the cloaca form?
anteriorly- bladder and definitive urogential sinus; posteiorrl-rectum/anal canal
What is formed when the cloacal folds fuse cranially
genital tubercle
What is found either sidde of the cloacal folds?
genital swellings
what do the genital swellings form?
scrotum and labia majora
What does the cloacal membrane divide into?
urogenital and anal membranes
what do the cloacal folds divide into?
urethral and anal folds
What does the urethral fold give rise to in females?
labia minora
