Reproductive Embryology Flashcards
source of gonads (as far as tissue and location)
thickened area of mesoderm develops on the medial side of mesonephros creating a bulge in week 5 — the gonadal ridge
indifferent gonads consist of
external cortex and internal medulla
in XX embryo, cortex _____ and medulla ____
in XY embryo, cortex ______ and medulla _____
forms ovaries; regresses
regresses; forms testes
gonads are indifferent until week ____
7
originate in the wall of the umbilical vesicle and migrate to gonadal ridges
primordial germ cells
primordial germ cells invest into the _____ and eventually form ____ or _____
gonadal cords
oocytes or sperms
directs gonad differentiaion
SRY gene for testis-determining factor (TDF)
TDF induces ________ to condense and extend into the medulla of the indifferent gonads, to form _______
gonadal cords
rete testis
thick, fibrous capsule that separates the gonadal cords from the surface
tunica albuginea
form interstitial (Leydig) cells that secrete androgen testosterone at week 8
Seminiferous tubules
where are sustenacular (Sertoli) cells and what do they do?
Seminiferous tubules
secrete mullerian inhibiting substance (MIS) aka antimullerian hormone
what does mullerian inhibiting substance do?
suppresses the formation of female structures
forms efferent ductules which eventually connect to ductus epididymis
rete testis
in ovary development, gonadal cords extend into medulla of ovary and form
rete ovarii
in ovary development, cortical cords extend from surface epithelium of developing ovary in to the underlying mesenchyme.
__________ move in.
cords create clusters called ________ which consists of an _______ surrounded by a singular layer of _________ from surface epithelium
active mitosis produces _________ before birth (many degenerate)
primordial germ cells
primordial follicles; oogonium; follicular cells
2 million primary oocytes
2 pairs of ducts in both male and female embryos
________ develop i male
________ develop in female
Mesonephric (Wolffian) ducts
Paramesonephric (Mullerian) ducts
in development of male genital ducts, fetal testes produce testosterone and MIS.
What do they do?
MIS - inhibits paramesonephric (Mullerian) duct formation
testosterone - stimulate mesonephric (Wolffian) duct formation
the mesonephric ducts are transformed into _____ and _______ and smooth muscle invests and forms
efferent ductules and duct of epididymis
ductus deferens
Three male glands
Seminal vesicle
prostrate gland
bulbourethral gland
lateral outgrowth from caudal end of each mesonephric duct forms
seminal vesicle
endodermal outgrowths arise from the prostatic part of the urethra to form
prostrate gland
develops from paired outgrowths from the spongy part of the urethra
bulbourethral gland
paramesonephric ducts develop ______ from unfused cranial parts
uterine tubes
caudal, fused portion of paramesonephric duct forms ______ which forms _____ and ______
uterovaginal primordium
uterus
superior portion of vagina
in development of vagina, epithelium from ENDODERM of ________ contacts _________
urogenital sinus
uterovaginal primordium
forms sinovaginal bulbs that fuse to form vaginal plate
sinus tubercle
in vaginal plate, central cells break down to form ______
lumen of vagina
persistent membrane formed by invagination of posterior wall of urogenital sinus
hymen
external genitalia and undifferentiated up to week ___ and characteristics appear during week ____. Fully differentiated by week ____
7
9
12
The genital tubercle forms in week 4 from mesenchyme, then what?
labioscrotal swellings and urogenital folds develop on either side.
tubercle elongates to form primordial phallus
male external genitalia:
primordial phallus enlarges and elongates to form
penis
male external genitalia:
urogenital folds form lateral walls of ______ on ventral surface of penis
folds fuse to form _____
urethral groove
spongy urethra
male external genitalia:
at the ________ and ectodermal ingrowth extends inward to meet spongy urethra and canalizes
glans penis
male external genitalia:
circular ectodermal ingrowth occurs in the periphery of the glans penis and forms the
prepuce (foreskin)
male external genitalia:
mesenchyme in the phallus forms ________ and _______ erectile tissue
corpora cavernosa
corpus spongiosum
male external genitalia:
labioscrotal swellings grow toward each other and fuse to form scrotum - this forms the
scrotal raphe line
female external genitalia:
growth of phallus gradually decreases to form
clitorus
urogenital folds do not fuse anteriorly, but form
labia minora
labioscrotal folds do not fuse, but form
labia majora
testes descend retroperineally from _____ to ______
posterior abdominal wall to deep inguinal rings
descent of testes is induced by _____ by week _____ and takes ______ (length of time)
androgens by week 26
2 to 3 days
the descending testes carry _____ and ______ with it while getting covered with
ductus deferens
vessels
layers of abdominal wall
layers of abdominal wall:
transversalis fascia becomes
internal oblique muscle becomes
external oblique aponeurosis becomes
internal spermatic fascia
cremaster muscle and fascia
external spermatic fascia
attached to uterus near the attachment of uterine tube, for descent of ovaries
gubernaculum
the gubernaculum does NOT pull ovaries down. The cranial part becomes ____ and the caudal part becomes _____
ovarian ligament
round ligament
undescended testes
cryptorchidism
ambiguous genitalia (hermaphrodite no longer used)
intersex
46, XX
error in sex determination giving both testicular and ovarian tissue; phenotype male or female but genitalia always ambiguous
ovotesticular DSD - true gonadal intersex
inadequate production of testosterone and AMH by fetal testes, testicular development ranges from rudimentary to normal
46 XY DSD
exposure of fetus to excessive androgens in utero - masculinization of external genitalia but no ovarian abnormality
46 XX DSD
“testicular feminization syndrome”
failure of masculinization
androgen insensitivity syndrome (AIS)
