8-D Development of the Reproductive System Flashcards
What is the embryonic origin of the urethra and vestibule?
cloaca
What is the embryonic origin of the external genitalia?
genital swellings
What is the embryonic origin of the gonad and duct system?
urogenital ridges
The intermediate mesoderm aka_______ _____ gives rise to the gonad and duct system as well as the kidney and the duct system.
urogenital ridge
Two ducts travel the length of the urogenital ridges, name them.
mesonephric duct (vas deferens and the seminal vesicles) and the paramesonephric duct (uterus and part of the vagina), these ducts are accompanied by the primitive gonad (testes or ovaries)
The mesonephric duct empties into the ___ ____ of component of the cloaca, the paramesonephric duct ends blindly in the tissue between the ______ and ____ _____
urinary bladder; bladder and the anorectal canal
The cranial end of the paramesonephric duct opens into the _______ cavity
peritoneal
The partitioning of the cloaca creates what two structures?
the rectum/anus and the bladder/urethra
What is the finger-like projection of the bladder into the umbilical cord?
allantois
Name the 3 genital swellings
genital tubercle (penis or clitoris), labioscrotal folds (labia major, scrotum) and the urogenital folds (labia minora and ventral penis)
Name the derivatives of the genital tubercle, urogenital/urethral folds and labioscrotal folds
penis/clitoris, ventral penis/labia minor and scrotum.labia major
Describe the indifferent stage of gonadal development.
mesonephric and para mesonephric duct are in place, a segment of each urogenital ridge forms a primitive gonad, primary sex cords form by the ingrowth of coelomic epithelium and germ cells migrate from the gonad from the yolk sac
The determination of gonadal sex is determined by ______ while the determination of the genital sex is governed by _______ factors
genes, hormonal factors
What happens in determination of male gonadal sex?
SRY region on the Y chromosome cause the primitive sex cords to form the seminiferous tubules containing sertoli cells that help in germ cell production and the leydig cells the produce testosterone
What happens during the determination of female gonadal sex?
in the absence of the Y chromosome, primitive sex cords break down and cells become follicular cells that associate with the germ cells
The male reproductive duct system develops largely from _________ ducts.
mesonephric (the paramesonephric ducts largely regress/disappear)
Differentiation of the vas deferens and epididymis form the mesonephric duct is mediated by____ while differentiation of prostate, seminal vesicles and external genitalia is mediated by ________ . (regression of the paramesonephric ducts is mediated by ____ ___ ___
testosterone, dihydrotestosterone, Mullerian Inhibiting Factor
Testicular descent along the gubernaculum and final positioning of the testis in the scrotum is largely under the influence of_______
testosterone
The female reproductive duct system develops largely from the ______ ducts
paramesonephric ducts
How does the uterus form form the paramesonephric ducts?
paramesonephric ducts fuse across the midline to form the uterus and the uterine tubes and part of the vagina
Name the two vestiges of the gubernaculum in the female.
ovarian ligament and round ligament of the uterus
What tissue provides for the completion of the urtero vaginal canal?
sinuvaginal bulbs (20% of lower vagina) made of endoderm that grow to meet the fused paramesonephric ducts and cavitate to form the lower vagina
What is the vestibule?
the space between the labia minora into which the vagina and urethra open
Female external genital development involves ______ growth while development of the male external genital involves growth and extensive fusion of the the _____ and ______ folds across the midline
primary; urethral and labioscrotal folds
Endoderm growing along then ventral surface of the forming penis becomes what?
penile urethra
The component of the uretrha int eh glans forms by an ingrowth of the _____ from the tip of the glans.
ectoderm
What is the name of the portion that must fuse along the ventral side of the penis?
penile and scrotal raphe
What is hypspadias?
failure of the fusion of the urogenital folds
What are variants that can occur if you the paramesonephric ducts don’t fuse properly?
bicornate and unicornuate uterus
During the growth of the genital tubercle an outgrowth of endoderm from the first part of the urethra growing along the ventral surface (urethral plate/urethral groove) develops into the penile ____-
urethra
What is considered the committed step in gonadal differentiation?
differentiation of primitive sex cords
