Development of the Reproductive System Flashcards
urinary and genital systems both develop from a common mesodermal ridge called _____
intermediate mesoderm
intermediate mesoderm bulges into the intraembryonic coelmic cavity to create the _____
urogenital ridge
the urogenital ridge differentiates into ____ and _____
- nephrogenic cord/ridge
- genital ridge
primordial germ cells originate from the ____ of the ____
endoderm; yolk sac
PGCs migrate along the ____ to invade the ____ around week 6
dorsal mesentery; genital ridges
in the genital ridge, epithelium proliferates and epithelial cells penetrate underlying mesenchyme to form _____ (at this point it is impossible to differentiate between male and female- indifferent gonads)
primitive sex cords
during the indifferent gonad phase, both males and females have two ductal systems:
- mesonephric (Wolffian) ducts
- Paramesonephric (Mullerian) ducts
paramesonephric ducts initially run ____ to mesonephric ducts; will cross ventrally and run ____ (in females)
laterally; caudomedially
cascade caused in males by 44+XY (Y influence)
indifferent gonad –> testis –>medually cords develop, no cortical cords, thick tunica albuginea
what happens in females because of 44 + XX (absence of Y)
indifferent gonad –> ovary –> medullary cords degenerate, cortical cords develop, no tunica albuginea
the Y chromosome contains the ____ gene which stands for _____
SRY; “sex determining region of the Y chromosome”
the SRY gene codes for ____, which stands for ____ and will lead to the development of the ____
TDF; testes determining factor; testes
the gonads will arise from ____ within the ____ of the embryo
intermediate mesoderm; genital ridges
the genital ducts will arise from paired _____ ducts
mesonephric
under influence of TDF, primitive sex cords continue to proliferate and penetrate into the ____, which is the central portion of the ____ (i.e. the developing testes)
medulla; genital ridge
the proliferation of the primitive sex cords forms the ___ or ____
testis cords or medually cords
towards the ____ (or lateral portion to the medulla), the testis cords break up and give rise to the tubules of the _____
hilum; rete testis
fibrous connective tissue that separates the testis cords from surface epithelium
tunica albuginea
the testis cords are composed of ____ and ____
primitive germ cells; sustentacular cells (Sertoli cells)
the sustentacular cells or Sertoli cells are derived from _____, secrete ____, and support _____
surface epithelium; AMH (also called MIS); spermiogenesis
the cell population within the empty space found between the testis cords is made up of ____ or _____
interstitial cells; Leydig cells
interstitial/Leydig cells are derived from _____ and secrete _____
mesenchyme of the genital ridge; testosterone
Around month 4, testis cords become _____ shaped
horseshoe
AMH stands for ____ and MIS stands for _____; both substances influence the degeneration/regression of the paramesonephric ducts (also called Mullerian ducts)
anti-Mullerian hormone; Mullerian-inhibiting substance
at approximately the 8th week of development, testosterone is secreted by the Leydig cells, which induces masculine differentiation of ____ and _____
mesonephric ducts; external genitalia
the testis cords remain solid until puberty, at which they develop a ____ and are called the _____
lumen; seminiferous tubules
the seminiferous tubules then join with the ____, which will enter the _____
rete testis tubules (or cords); ductuli efferentes (efferent ductules)
the ductuli efferentes (efferent ductules) link the ____ and _____
rete testis; mesonephric duct
the mesonephric duct will become the _____
ductus deferens (vas deferens)
the genital ducts in males are stimulated to develop by ____ and are derived from the _____
testosterone; mesonephric kidney system
mesonephric ducts open into _____ on either side of the ____
urogenital sinus; sinus tubercle
genital ducts in males
efferent ductules lead to (1) epididymis –> (2) ductus deferens –> (3) seminal vesicle –> (4) ejaculatory duct
under the control of AMH, the _____ degenerates, except for a small portion of the cranial end called the _____
paramesonephric duct; appendix testis
the _____ or ____ is an outpocketing of the urethra
utriculus prostaticus ; prostatic utricle
the testes develop ____ in the abdominal region and must pass through the abdominal wall to the reach the ____; passage occurs through the _____
retroperitoneally; scrotum; inguinal canal
the _____ extends from the caudal pole of the testis, anchors it to the scrotum and guides its descent
gubernaculum
descent occurs primarily due to the growth of the cranial end of the ____away from the future ____ region; this descent through the inguinal canals is controlled by ____
abdomen; pelvic; testosterone
passage through the inguinal canals may also be aided by increase in _____ resulting from growth of _____
intra-abdominal pressure; abdominal viscera
during descent of the testes, the _____ of the abdominal cavity forms evagination on each side of the midline into the ____ abdominal wall; this is the ____, which follows the path of the gubernaculum into the scrotal swellings
peritoneam; ventral; vaginal process or processus vaginalis
as testes descend through the inguinal ring, they get covered by:
- processus vaginalis: visceral layer of tunica vaginalis & parietal layer of tunica vaginalis
- Transversalis fascia: internal spermatic fascia
- internal abdominal oblique muscle: cremasteric fascia and muscle
- external abdominal oblique muscle: external spermatic fascia
_____ does not contribute a layer to the testes
transversus abdominis m.
because females have no Y chromosome, they have no ___ or ____
SRY; TDF
_____ dissociate into clusters which occupy the ____ part of the ovary
primitive sex cords; medullary
surface epithelium continues to proliferate which gives rise to the ____ in females
cortical cords
cortical cords split into isolated cell clusters; cells in clusters continue to proliferate & surround ____ with _____
oogonium; follicular cells
oogonia (or primary oocyte) + follicular cells = _____
primordial follicle
in females, with the presence of estrogen and the absence of testosterone and AMH:
- mesonephric ducts regress
- paramesonephric ducts develop into main genital ducts
in females, paramesonephric ducts at first run ____ to mesonephric duct, then cross ____; at midline, they will meet with the paramesonephric duct on the opposite side
lateral; ventrally
the caudal tip of combined paramesonephric ducts projects into the ____ at the ____
posterior urogenital sinus; sinus tubercle
ovaries will descend, and paramesonephric ducts simultaneously form:
- uterine tube
- uterine canal
- corpus uteri
- cervix
- upper portion of vagina
when the caudal tip of the paramesonephric duct hits the urogenital sinus, two _____ proliferate and form solid _____
sinovaginal bulbs; vaginal plate
wing like expansions of the vagina around the end of the uterus
vaginal fornices
____ continues to grow cranially, increasing distance between uterus and urogenital sinus
vaginal plate
the vagina has dual origin; upper portion from ____ and lower portion derived from _____
uterine canal; urogenital sinus
the ____, which is a plate of ____ cells, separates the vagina from the urogenital sinus
hymen; endoderm
as the ovaries descend, fused folds of peritoneum coming from lateral walls create the ____
broad ligament
cranial genital ligament forms the _____
suspensory ligament
caudal genital ligament forms the _____ and _____
round ligament of the ovary; round ligament of the uterus
in females, during the 3rd week, ____ from the primitive streak migrates around the cloacal membrane to form ____
mesenchyme; cloacal folds
the cloacal folds fuse cranial to the cloacal membrane and create the _____
genital tubercle
caudal cloacal folds form the ____ and ____ folds
urethral; anal
genital swellings become visible and will become the ___ in males and the ____ in females
scrotal swellings; labia majora
in males, external genitalia characterized by rapid elongation of ____, now called the ____
genital tubercle; phallus
the phallus pulls ____ forward to form the lateral walls of the _____
urethral folds; urethral groove
epithelial lining of the urethral groove; originates from _____
urethral plate; endoderm
external genitalia in males influenced by _____
androgens
at the end of the 3rd month, two urethral folds close over the urethral plate, forming the ____, which does not extend to the tip of the ____
penile urethra; phallus
the distal end of the phallus is formed during the 4th month, when _____ cells penetrate inward to form short _____
ectodermal; epithelial cord
later, the cord will obtain a lumen and will be called the _____
external urethral meatus
the penile urethra has both ____ and ____ origination
endoderm; ectoderm
scrotal swellings arise in ____ region and move ____
inguinal; caudally
scrotal swelling makes up half of the scrotum, the two are separated by the ____ (line of fusion of scrotal swellings)
scrotal septum
in the female, the genital tubercle elongates slightly to form the ____
clitoris
the urethral folds do not fuse and develop into the _____
labia minora
genital swellings enlarge and form the _____
labia majora
urogenital groove is open and forms the ____
vestibule
external genitalia in females influenced by ____
estrogens
pituitary gland develops from two sources:
- ectodermal outpocketing of stomodeum (developing moouth), which is Rathke’s pouch
- downward extension of the diencephalon, called the infundibulum (nervous tissue)
Rathke’s pouch grows ____ towards the infundibulum and will lose its connection with the ____ (ends up in area of sphenoid bone)
dorsally; oral cavity
cells in anterior wall of Rathke’s pouch form _____ or anterior lobe
adenohypophysis
an extension of the adenohypophysis, the _____, grows along infundibulum and surrounds it
pars tuberalis
the posterior wall of Rathke’s pouch forms _____, or the posterior lobe
pars intermedia
infundibulum gives rise to the ____ and the ____
stalk; pars nervosa
the pituitary gland is the connection between the ____ and ____ systems
nervous; endocrine
