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Flashcards in Embryology* Deck (19)
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1
Q

which germ cell layer gives rise to the urogenital system

A

mesoderm

2
Q

how do the primordial germ cells get to the genital ridge

A

use the gut tube and its mesentery as a guide

3
Q

what do the primordial cells join to at the genital ridge

A

proliferating body epithelium which becomes primitive sex cords

4
Q

in males what happens to the primitive sex cords

A

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

5
Q

what happens to the primitive sex cords in females

A

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

6
Q

in mesonephric duct how does the epididymis form

A

the area close to the duct the tubules become highly coiled to form the epididymis

7
Q

what happens to the paragenital tubules in males

A

they begin to degenerate - can occasionally get some remnants

8
Q

what happens to the paramesonpehric duct in males

A

degenerates but can get remnant - urticulus prostaticus

9
Q

how do the seminal vesicles develop in males

A

as an out spreading of the mesonephric duct

10
Q

what pulls the testis down into the scrotum
and how
does it degenerate

A

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

11
Q

descent of the testis - which layers does it cross and which layers get attaches

A

transverse fascia -> internal spermatic fascia
transverse abdnominus muscle
internal oblique -> cermasteric fascia and muscle
external oblique -> external spermatic fascia

12
Q

paramesonpehric duct in females how does it form a uterus and what else does it form with connection to what

A

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

13
Q

how is the vagina formed

A

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

14
Q

which germ cell layer does the vagina come form

what forms at the point of contact between the vagina and the outside world

A

endoderm

hymen which has small opening for passing of menstrual blood

15
Q

whats a bicornate uterus

A

septum has regressed completely but further up that the double uterus - kind of looks like one uterus

16
Q

whats a separated uterus

A

a septum has formed down the uterine cavity

17
Q

whats a unicorn ate uterus

A

failure of one duct

18
Q

whats a cervical atresia

A

no communication between the vagina and the uterus

19
Q

how do the ovaries descend

A

also via gubernaculum which goes through the inguinal canal and gets stuck on the paramesonephric duct so when it goes down again it pulls them together causing them to fuse
as they fuse they create the broad ligament