EX3 Embryology - Genital System Flashcards
What germ layer is the genital system derived from
intermediate mesoderm
Intermediate mesoderm thickens at week 5 to form what precursor to the genital system
gonadal ridge
At what week do the visible differences of the genital system show
week 7
weeks 1-6 are the “indifferent stage”
The sex of an individual is determined at what stage
conception
What are the two ducts that are precursors to the male/female gonads
males - mesonephric (Wolffian) duct
females - paramesonephric (Müllerian) duct
The mesothelium lining of each gonadal ridge thickens to form what
mesothelial cells = gonadal cord cells
The mesothelial cord cells form what
solid gonadal cords that sink into underlying mesenchyme to “welcome” PGCs
SRY codes for what
TDF; testes-determing factor
These develop from mesenchyme of gonadal ridge and produces testosterone
leydig cells
These develop from gonadal cord cells and forms the seminiferous tubules and rete testes
sertoli cells (“caretakers of PCGs”)
How are seminiferous tubules formed
by an invagination of cord cells
What induces the mesonephric duct to form male genital ducts and external genitalia
testosterone
Testosterone causes the mesonephric ducts and mesonephric tubules to do what
puncture the region of the gonadal ridge where testicles are developing to form the ductus deferens, epididymis, and efferent ductules connections
The mesonephric duct becomes what in males
ductus deferens
The superior end of the mesonephric duct becomes what in males
epididymis
The mesonephric tubules become what in males
efferent tubules
The caudal ends of mesonephric ducts develop what
seminal vesicles and ejaculatory ducts which open into prostatic urethra
The Müllerian duct reman at becomes what in males
appendix testis
The Müllerian duct regresses in males due to which cell signalsing
Sertoli cells; produces MIH (Müllerian-inhibiting hormone)
The prostate and bulbourethral glands are endodermal outgrowth from what
urogenital sinus
This extends from the gonad to the labioscrotal swelling
gubernaculum
The descent of the testes begins in which weeks and ends when
begins week 26; both testes in scrotum by week 32
What is the gubernaculum
it is a ligament that as it shortens, it pulls the testis, ductus deferens, and testicular vessels downward traversing the inguinal canal to the scrotal sac
Where are the layers of the spermatic cord derived from
anterior abdominal wall muscular layers/fascia that are dragged inferiorly with the testes
This is the development of fluid-filled cysts of the testes/spermatic cord
hydrocoele
This is the failure of the testes to descend
crytochidism
True or False
The female genital system contains SRY and TDF
False; it does not
Where do the stromal cells of the developing ovary originate from
mesenchyme of gonadal ridge
Follicular cells (“caretakers” of the PGCs” develop from what
gonadal cord cells
These envelop PGCs
cortical cords (comprised of cord cells)
Cortical cords break up into pieces, and cord cells develop into what
flat follicular cells that surround each oogonium
The primary oocyte plus the follicle cell capsule makes up what
primordial follicle
Due to low testosterone in females, what happens
mesonephric ducts regress
Due to no MIH in females, what happens
continued grout and development of Müllerian ducts
Epoöphoron, paraöphoron, and gartner duct cysts are what in females
remnants of mesonephric duct
The cranial end of the Müllerian ducts form what
uterine tubes
The caudal end of the Müllerian ducts fuse to form what
uterovaginal primordium; which forms the uterus and superior vaginal canal
The uretovaginal primordium comes in contact with dorsal wall or urogenial sinus and induces the formation of what
sinovaginal bulbs; pair of endodermal outgrowths
The sinovaginal bulbs fuse with the uretovaginal primordium forming what
the vaginal plate (inferior vagina)
formed from urogenital sinus
The vaginal canal forms from what
the degeneration of the vaginal plate central endodermal cells
What are the endodermal outgrowths from the urogenital sinus
greater vestibular glands
urethral glands
paraurethral glands
The gubernaculum in females forms what
the ovarian and round ligament
The genital tubercle forms what in males/females
males - glans penis (head)
females - clitoris
The labioscrotal swelling (genital swelling) forms what in males/females
males - scrotum
females - labium majus
The urethral folds form what in males/females
males - penile shaft
females - labium minus
