Embryology* Flashcards
which germ cell layer gives rise to the urogenital system
mesoderm
how do the primordial germ cells get to the genital ridge
use the gut tube and its mesentery as a guide
what do the primordial cells join to at the genital ridge
proliferating body epithelium which becomes primitive sex cords
in males what happens to the primitive sex cords
continue to develop and organise themselves into horse shoe shaped structures
towards the hilum they break off into thinner structures for releasing sperm
germ cells form the semi tubules which do not fully develop until puberty when they form a lumen
what happens to the primitive sex cords in females
they break apart
individual primitive germ cells get surrounded by somatic support cells and form follicles that are initially deep in the ovary and move out into the cortex
in mesonephric duct how does the epididymis form
the area close to the duct the tubules become highly coiled to form the epididymis
what happens to the paragenital tubules in males
they begin to degenerate - can occasionally get some remnants
what happens to the paramesonpehric duct in males
degenerates but can get remnant - urticulus prostaticus
how do the seminal vesicles develop in males
as an out spreading of the mesonephric duct
what pulls the testis down into the scrotum
and how
does it degenerate
the gubernaculum which is a ligamentous structure that runs form the tests into the inguinal ring and then goes down to the scrotum
it shortness as development goes on and at the third month pulls the testis down into the deep inguinal ring where it stays till month 7
during that time an extension of the peritoneum forms the process vaginalis
the second shortening of the gubernaculum pulls the testis down into the scrotum and then the vaginalis loses its connection with the peritoneal cavity forming the tunica vaginalis
remnants of the gubernaculum stay in place as it helps anchor the testis to the floor of the scrotum - without this can get rotation of the testis
descent of the testis - which layers does it cross and which layers get attaches
transverse fascia -> internal spermatic fascia
transverse abdnominus muscle
internal oblique -> cermasteric fascia and muscle
external oblique -> external spermatic fascia
paramesonpehric duct in females how does it form a uterus and what else does it form with connection to what
initially runs alongside the developing gonadsas it comes down into the pelvis both of them move towards one another and at the midline they fuse to form the uterus - the wall between them breaks and they form a single cavity
also make contact with the urogenital sinus which is the site of the vagina
how is the vagina formed
the uterus/paramesonpehric ducts proliferate with the urogenital sinus forming sinovaginal bulbs which continue to proliferate and gradually push that point of contact further away - then they begin to capitate to form the vagina and a connection into the uterus
which germ cell layer does the vagina come form
what forms at the point of contact between the vagina and the outside world
endoderm
hymen which has small opening for passing of menstrual blood
whats a bicornate uterus
septum has regressed completely but further up that the double uterus - kind of looks like one uterus
