i hate embryos Flashcards
what is the indifferent stage of development
for the first 6-7 weeks, males and females are phenotypically indistinguishable.
what is gonadal tissue derived from
mesoderm adjacent to the mesonephros
describe migration of germ cells
they migrate from the yolk sac along the allantois, followed by dorsal mesentary into genital ridges adjacent to mesonephric region
what are genital ridges
area encompassing coelomic epithelium and primitive sex cords
what is absolutely essential for gonad development
germ cells
what can happen with abnormal germ cell migration
teratomas
what does SRY gene encode for
testis determining factor (TDF)
describe functions of TDF
stimulates differentiation into testes and forming of primary sex cords, promoting formation of leydig cells and sertoli cells
what happens without TDF
male structures do not differentiate, leading to development of ovaries and secondary sex cords
primitive sex cords develop from…
coelomic epithelium
what do primitive sex cords form in males
rete testis and seminiforous tubules
where are primitive sex cords located
in the medulla
what is testosterone needed for in terms of developing structures
epididymis, vas deferens, seminal vesicles
what is DHT
hormone made from testosterone via 5a-reductase
what is DHT important for developing
penis, scrotum, prostate
what is the penis derived from
genital tubercle
what is the scrotum derived from
genital swellings
what is the prostate derived from
urethral epithelium
what happens with the primitive sex cords in females
it degenerates
what happens with coelomic epithelium in females
it expands to form the cortical region aka cortex. this happens as the medulla (primitive sex cord) degenerates
what is important to female development in terms of hormones
lack of DHT and MIH
what do the mesonephric ducts become in males
epididymis, ductus deferens, seminal vesicles, ejaculatory duct
what do mesonephric tubules become in males
efferent tubules
what do paramesonephric ducts become in males
not much; partially the appendix testis and prostatic utricle
what do the mesonephric ducts become in females
mostly degenerate, but can form gartner’s duct/cyst and the appendix of the ovary
what do mesonephric tubules become in females
largely degenerate, but partially epoophoron and paraoophoron
what do the paramesonephric ducts become in females
uterine tubes, uterus, cervix, superior third of the vagina
what helps form the uterus and upper third of the vagina
fusion of caudal aspects of mesonephric ducts
when does descent of the testes begin
weeks 10-14
when is descent of testes complete
can finish after birth, but usually descend into the scrotum during the 7th month
what pathway do the testes take into the scrotum
a retroperitoneal pathway
what guides the descent of the testes
the gubernaculum
the descent of the testes forms which structures
deep ring, inguinal canal, and superficial ring
what happens if there are defects in the processus vaginalis
herniation of abdominal contents (indirect hernia) if it is completely patent, hydrocele if partial
what stabilizes the ovaries cranially
suspensory ligament of the ovary
what stabilizes the ovaries caudally
round ligament of the ovary
what does the urogenital sinus form
bladder, urethra, vaginal vestibule
what does the mesonephric ligament form in males
gubernaculum testis
what does the mesonephric ligament form in females
round ligament of the ovary/uterus
what does the genital tubercle form in males
penis
what does the genital tubercle form in females
clitoris
what do genital folds form in males
floor of penile urethra
what do genital folds form in females
labia minora
what results from congenital adrenal hyperplasia
female pseudohermaphroditism
what causes testicular feminization
androgen insensitivity
what is hypospadias
opening of urethra on the ventral surface of the penis due to urethral folds not closing properly
what is epispadias
opening of the urethra on the dorsal surface of the penis
