Development of the Genital System Flashcards
during what week does sexual differentiate begin
week 7
at what week can male and female genitalia be recognized?
week 12
at what week are phenotypic differentations complete
week 20
primordial germ cells are specified in what early germ layer?
epiblast layer
around week 5, the primordial germ cells migrate up the dorsal mesentery to enter what structure
the genital ridge
somatic support cells in males and females
males: sertoli cells
female: follicle cells
somatic support cells originate from what structure/cell type
proliferating body epithelium cells displaced by germ cells
both mesonephric and paramesonephric ducts in the embryo develop from what layer
intermediate mesoderm
the mesonephric duct is also known as the _____ duct
wolffian duct
part of early kidney development
the paramesonephric duct is also known as the ____ duct
mullerian duct
in males, the wolffian duct (derived from the _____ duct) remains to form what structures
mesonephric - epididymis, vas deferens, seminal vesicles, ejaculatory ducts
in females, the mullerian ducts (derived from the _____ duct) remains to form what structures
paramesonephric - oviduct, uterus, upper vagina
sexual dimorphism is dependent on what chromosome
Y chromosome but also dependent on autosomes as well
what is the sex determining region of the y chromosome
the SRY gene
the SRY gene determines what
gonad type
which determines duct and genitalia development
in the absence of SRY, development of what phenotype occurs
female
SRY gene is expressed in what cell type
the somatic support cells (pre-sertoli)
sertoli cells surround primordial germ cells to organize seminiferous tubules
a subset of undifferentiated tubular cells are induced by the _____ cells to produce what hormone
what are these cells called
sertoli cells
testosterone
leydig cells
what is the major transcription factor driven by SRY gene
sox9
what is the primary target of sox9 gene
anti-mullerian hormone
results in regression of mullerian (paramesonephric) duct between weeks 8-10
the \_\_\_\_ cells drive mesonephric ducts to form efferent ductules epididymus vas deferens seminal vesicles
leydig cells
derivatives of the mesonephros
efferent ductueles
epididymus
vas deferens
seminal vesicles
fetal leydig cells produce what two enzymes
testosterone (weeks 8012) driven by HCG from placenta
induces mesonephric duct to form ductus deferens, epididymus, seminal vesicles
5alpha reductase to turn testosterone into dihydrostestosterone which induces
genital tubercle to become penis
genital swellings to become scrotum
urethral epithelium to form prostate
adult leydig cells produce what hormones to drive what differentiation
andorgens
initiation of spermatogenesis
masculinization of brain
male sexual behavior
products of sertoli cells
AMH (regression of paramesonephric duct)
Androgen binding factor (spermatogonia –> spermatazoa)
seminal vesicles are derived form what duct
mesonephric dcut
intermediate mesoderm of urogenital ridge
prostate is formed by buds of _____ from the UG sinus in t he region of pelvic urethra during what week
buds of endoderm
week 10
prostate and _____ are derived from endoderm
bulbourethral glands
rupture of cloacal membrane opens phallic portion of urogenital sinus to exterior forming endodermally lined plate called the ______ plate
urogenital plate
remnants of cloacal membrane at the ventral end of the urogenital plate and adjacent genital tubercle
glans plate
swelling of mesoderm covered by ectoderm at the vetnral and cranial end of phallic portion of urogenital plate
genital tubercle
_____ drives lengthening and growth of genital tubercle and fusion of labioscrotal swellings to form scrotum
Dihydrotestosterone
in the presence of DHT, the labioscrotal swellings fuse to form what adult structure
scrotum
second most common birth defect after cryptorchidism
hypospadias
urethral folds didnt fuse
without the SRY gene, what transcription factor is able to suppress SOX9
Wnt-4
along with wnt4, what transcription factor suppresses SOX9 constantly
FOXL2
somatic cells not under the signal of Sox9 form what type of cells
follicle and primoridal germ cells (–> oogonia)
without sertoli cells, no AMH is produced, therefore the ____ ducts develop and form
the paramesonephric ducts develop and fallopian tubes, uterus, and upper portion of vagina are formed
without leydig cell, the signal to retain the ____ duct is lost
wollfian (mesonephric)
fusion of the ______ _____ ducts form the uterus
fusion of the inferior paramesonephric ducts
uterine tubes are the unfused portion of the ________ ducts
paramesonephric ducts
the upper vagina is derived from ________
the lower vagina is derived from ________
upper - mesoderm
lower - endoderm
the superficial vagina begins as what structure
sinovaginal bulbs
without the signal of DHT, the genital tubercle is not lengthened and the urogenital folds dont fuse resulting in what two structures
labia minora
labia majora
formation of the broad ligament
midline fusion of the parameso0nephric ducts brings lower urogenital ridge within the pelvic cavity and its covered inn peritoneum
upon completion of uterus and oviduct formation, the remaining tissue thins forming a double fold of peritoneum
congenital conditiosn in which development of chromosomal, gonadal, and anatomic sex is atypical
disorders of sex development
XY DSDs
XY 46 ahs testis but phenotype is female
caused by
inadequate testosterone synthesis
17 beta hydroxysteroid dehydrogenase 3
androgen insensitivity syndrome
5-alpha reductase deficiency
mutations in AMH or AMH receptor
characteristics of androgen insensitivity syndrome
commonly caused by loss of fucntional androgen receptors
have testis but no spermatogenesis; testosterone levels may be high
testosterone at puberty is metabolized to estradiol initiating female secondar ycharactersitics but patients exhibit amenorrhea
no uterus or uterine tubes; vagina is short and ends blindly
5 alpha reductase deficiency
46 XY genotype
autosomal recessive
normal testis and duct system
underdeveloped male external genitalia
depending on level of deficiency, can exhibit external female phenotype
congenital adrenal hyperplasia
most common cause of female sexual ambiguity
46 XX
have ovaries but produce androgens
masculinization of the female external genitalia; may even exhibit fusion of labia giving appearance of scrotum
ovotesticular disorders
true interseexuality
have both testicular and ovarian tissue
ambiguous external genitalia or predominatnly female; usually have a uterus
caused by: translocation of piece of Y onto X, subset of cdells may have mutation in Y, oanomaly in sex determination and differentiation of primoridal germ cells
