Urogenital Embryo Flashcards
Where do primordial germ cells originate? What germ layer do they end up in?
Epiblast (yolk sac specifically)- end up in endodermal cells
What type of tumor results from an abnormal migration of primordial germ cells?
Extragonadal germ cell tumor
What are the genital ridges a proliferation of?
Coelomic epithelium - forms germinal epithelium, outermost layer of male and female gonads
Migration of what induces development of the gonad into ovary or testis?
Primordial germ cells invading genital ridges
What is the source of ovarian cancer and endometriosus?
Coelomic epithelium
What gene on the Y chromosome determines if testis will develop?
SRY
What protein does the SRY gene produce?
TDF - testis-determining factor
What are the three cell types present in the testis cords?
Primitive germ cells, Sertoli (sustentacular) cells, Leydig (interstitial) cells
When do testis cords acquire a lumen and become seminiferous tubules?
Puberty
What is the embryological origin of the vas deferens?
Mesonephric duct
What type of cords proliferate in the female?
Cortex/cortical (secondary) cords
What type of cords proliferate in the male?
Medullary (primitive sex) cords
What do the cortical cords in the female transform into?
Follicular cells
What genes does TDF induce downstream?
Mullerian inhibitory substance (MIS), testosterone
What type of cells produce Mullerian inhibitory substance (MIS)? What does it do?
Sertoli cells - causes regression of paramesonephric ducts
What type of cells produce testosterone? What does it do?
Interstitial cells of Leydig - mediates virilization of mesonephric duct
What does testosterone get converted into? What does it do? What enzyme does this?
dihydrotestosterone (DHT) - acts on external genitalia
5a reductase
What would you see clinically if someone has issues making DHT but not testosterone?
Female genitalia but internal testosterone influence
What is the name of the genital duct in males?
Wolffian/Mesonephric
What is the name of the female genital duct?
Mullerian/Paramesonephric duct
What are the remnants of the Mullerian duct in males called?
Utriculus prostaticus
What are the remnants of the Wolffian duct called in females?
Epoophoron, paraoophoron, Gartner’s cyst
What clinical correlation is remnants of the paramesonephros?
Paraovarian cysts
What results from an imperforate hymen?
Metrocolpus - uterus fills w/ menstrual fluid b/c there is nowhere to go
What types of cells form the external genitalia around the cloacal membrane?
Mesenchymal cells
What syndrome does XXY result in?
Klinefelter’s
What syndrome does a single X result in?
Turner’s
What is female pseudohermaphroditism?
Biochemical defect in steroid production - you make a lot of sex steroids, so this personw ould have uterus and ovaries but ambiguous genitalia
What is male pseudohermaphroditism?
Caused by decrease in androgenic hormones - tissues do not respond to DHT, so there are testes, but also a short blind vagina
What is hypospadias? Epispadias?
When urethral groove doesn’t close completely inferiorly
When urethral groove doesn’t close completely superiorly
How do uterine anomalies result?
When Mullerian ducts don’t connect with each other correctly
In the female, what forms from the urogenital sinus?
Urinary bladder, urethra, lower vagina, vestibule, greater vestibular/urethral glands
In the male, what forms from the urogenital sinus?
Urinary bladder, urethra, prostate gland, bulbourethral/Cowpers glands
In the female, what forms from the mesonephric duct and tubules?
Ureter, renal pelvis, major and minor calices, collecting tubules
In the male, what forms from the mesonephric duct and tubules?
Efferent ductules, duct of epididymis, ductus deferens, ejaculatory duct, seminal vesicles, ureter, renal pelvis, calices, collecting tubules
In the female, what forms from the paramesonephric duct?
Uterine tubes, uterus, upper vagina
In the male, what forms from the paramesonephric duct?
Vestigial - appendix of testis
In the female, what forms from the genital tubercle/phallus?
Clitoris (glans, corpora cavernosa, bulb of vestibule)
In the male, what forms from the genital tubercle/phallus?
Penis (glans, corpora cavernosum, corpus spongiosum)
In the female, what forms from the urogenital folds?
Labia minora, perineal raphe, perianal tissue and external anal sphincter
In the male, what forms from the urogenital folds?
Ventral aspect of penis, most of penile urethra, perineal raphe, perianal tissue and external sphincter
In the female, what forms from the labioscrotal folds?
Labia majora
In the male, what forms from the labioscrotal folds?
Scrotum
In the female, what forms from the indifferent gonad?
Ovary - follicles from secondary sex cords in cortex
In the male, what forms from the indifferent gonad?
Testis - seminiferous tubules from primary sex cords, rete testis in medulla
In the female, what forms from the gubernaculum?
Ovarian ligament and round ligament of the uterus
In the male, what forms from the gubernaculum?
Gubernaculum testis
