57 terms

GA - Development of Reproductive System

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Urinary & genital systems develop from
ridge of intermediate mesoderm
urogenital ridge
Initial common urorectal cavity
cloaca
Development of gonads - 2 stages
initial - genital ridges form
developing - genital ridge populated by primordial germ cells
gonadal ridge epithelium --> primitive sex cords
Y chromosome contains what important gene?
SRY (sex-determining region on Y)
SRY gene controls synthesis of
testis-determining factor (TDF)
In males, primitive sex cords
continue to proliferate and penetrate into medulla as testis cords or medullary cords
In females, primitive sex cords
dissociate into future medulla
Medullary cords replaced by vascular stroma of ovarian medulla
___ separates testis cords from surface epithelium
tunica albuginea
Toward hilum, testis cords break up into
rete testis
Testis cords remain solid until
they acquire a lumen, forming seminiferous tubules, during puberty
Seminiferous tubules join
rete testis, which enter efferent ductules
What causes differentiation of genital ducts & external genitalia into male parts?
Testosterone production from interstitial cells (of Leydig)
In females, surface epithelium continues to proliferate, forming
cortical cords --> follicular cells --> oogonia
Primary follicle consists of
oogonia
follicular cells
What stimulates testes to secrete FGF9?
SRY
SOX9
SRY upregulates SF1 through
SOX9
SRY upregulates what protein to promote differentiation of Sertoli and Leydig cells?
SF1 - steroidogensis factor 1
Ovary determining gene (WNT4) upregulates what protein to inhibit SOX9?
DAX1
Ovary determining gene (WNT4) upregulates what genes?
TFII105 - promotes ovarian differentiation
Male genital duct system develops from
mesonephric (Wolffian) ducts
Female genital duct system develops from
paramesonephric (Mullerian) ducts
in the absence of Mullerian inhibiting substance
In males, mesonephric ducts give rise to
epididymis
ductus deferens
ejaculatory duct
seminal vesicles
In males, paramesonephric ducts form
prostatic utricle
appendix testis
In females, paramesonephric ducts form
upper portion of vagina
endometrial lining of uterus
fallopian tubes
In females, mesonephric ducts form
epoophoron
paraoophoron
Gartner's glands
Sino-vaginal bulbs form
lower 2/3 of vagina
*Bicornuate uterus
failure of paramesonephric ducts to fuse
*Double uterus & vagina
failure of fusion of paramesonephric ducts AND sinovaginal bulbs
*Vaginal atresia
Failure of sinovaginal bulbs to develop or vaginal plate to canalize
*Cryptorchidism
Undescended testes due to decreased testosterone
Under the effect of testosterone, what helps the testes descend?
Gubernaculum testes
Gubernaculum testes becomes
scrotal ligament
Evagination of the peritoneum, aka
processus vaginalis
Processus vaginalis becomes
tunica vaginalis
Descent of testes creates
inguinal canal
*Indirect inguinal hernia caused by
persistence of processus vaginalis
*Congenital inguinal hernia
persistence of connection between processus vaginalis and scrotal sac after 1st year of birth
*Congenital hydrocele
partial persistence of cystic cavity during obliteration of processus vaginalis will be filled with serious fluid
Two cloacal folds unite to form
genital tubercle
Cloacal folds are subdivided into
urethral / urogenital folds
anal fold
Phallus formed from elongation of
genital tubercle in presence of androgens
Formation of clitoris due to
slowing of growth of genital tubercle by estrogen
Urethral folds become
penile urethra - fused, then canalized
labia minora - stay separated
Genital swellings become
scrotal swellings
labia majora
*Hypospadias
Incomplete fusion of urethral folds leading to abnormal openings along INFERIOR aspect of shaft of penis
*Epispadias
too far caudal genital tubercle causes opening on the DORSUM of the penis with exposure of the urethra
*Micropenis
Insufficient androgen stimulation
Prostatic and membranous parts of urethra arise from
pelvic part of urogenital sinus
Penile part of urethra arises from
urethral folds
Glandular parts of urethra arises from
surface (glans penis) epithelial proliferation
Prostate gland arises from
prostatic urethra
Urethral & paraurethral glands (female) arise from
cranial part of urethra
*Klinefelter syndrome
47XXY
male, tall, long extremities, gynecomastia, female hair distribution, infertility

Testicular atrophy, infertility
*Turner syndrome
45X
female, short stature, neck webbing, high arched palate, cardiac and renal anomalies, inverted nipples, shield-like chest, infertility, immature female external genitalia

ovarian dysgenesis (streak gonads)
*True hermaphroditism
ambiguous or predominantly female external genitalia

testes and ovaries
46XX
*Female pseudohermaphroditism
Ovaries present, masculine external genitalia

Congenital adrenal hyperplasia due to decreased steroid hormones, increased ACTH, excess androgen production, androgen administration during pregnancy

46XX
*Androgen insensitivity syndrome
Normal female external genitalia with blind vagina, testes present but no spermatogenesis

Male pseudohermaphroditism
Lack of androgen receptors
46XY