embryo Flashcards
when is the end of the undifferentiated stage of the embryo?
week 6
when does body folding occur?
week 4
when does gastrulation occur?
week 3
what is created from intermediate mesoderm?
urogenital system gonads ducts seminal vesicles upper vagina
what is created from endoderm?
prostate
lower vagina
bulbourethral glands/greater vestibular glands
when do the testes reach the inguinal area?
week 12
when do the testes migrate through the inguinal canal?
week 28
when do the testes reach the scrotum?
week 33
what happens during the 6th week?
germ cells migrate from the hindgut to the genital ridge (on medial aspect of urogenital ridge)
epithelium proliferates to primitive sex cords -> testes cords
what happens in males during week 8
formation of rete testes from testes cords
tunica albuginea forms
leydig cells produce testosterone
testes cords form seminiferous tubules
how does the descent of the testes work?
gubemaculum + genital ligament grow from inguinal region and guid the testes down
pulls gonadal a. and testicular v. with them
where do the coverings of the testes originate from?
ant. abd wall
what is cryptorchidism?
when one or both testes dont descend properly
what is hypospodias?
urethral folds dont fully close
what does the genital tubercle turn into?
female-clitoris
male- phalus
what do the genital swellings turn into?
male-scrotal swellings
female-labia majora
what do the urethral folds turn into?
male- urethra
female- labia minora
explain male differentiation of the ducts
SRY gene -> testes
sertoli cells -> MIS -> paramesonephric ducts degenerate
Leydig -> testosterone -> mesonephric ducts develop
what do the mesonephric ducts turn into in males?
epididymis vas deferens seminal vesicle ejaculatory duct urethra
what does the UG sinus turn into for males?
bladder urethra anus prostate bulbourethral glands
explain the female differentiation of the ducts
WNT4 gene -> ovary
estrogen -> paramesonephric ducts persist
no testosterone -> mesonephric ducts degenerate
what do the paramesonephric ducts in females create?
uterine tubes (unfused)
uterus (fused)
cervix (fused)
superior vagina (fused)
what does the UG sinus create in females?
inferior vagina
greater vestibular glands
paraurethral glands
what is a bircornate uterus?
incomplete fusion of the paramesonephric ducts
what happens in week 6 of a female embryo?
germ cells migrate -> primitive sex cords -> cell clusters (cortical cords) -> follicular and surround the germ cells that become the primary oocytes
