LEC33: Reproductive Tract I Flashcards
what directs gonad development
genotype
what directs external genitalia development
presence of external genitalia
cause of discordance re: gonads, phenotype
mutations- cause gonadal development and phenotype to be discordant
2 phases of development
embryonic development of sex organs, secondary sexual development (happens at puberty)
embryonic development of sex organs includes
gonads (testes, ovaries), genital ducts, accessory glands
layer of embryonic tissue > reproductive organs
intermediate mesoderm
basis of primordial germ cells
endodermally-derived yolk sac
what/when is indifferent gonads period
male/female gonads, genitalia are identical
5-7 weeks
when primoridal germ cells migrate
Begins week 4 done by week 6
takes 2 weeks
during indifferent gonads pd
what is genital ridge
thickening of medial side of mesonephros
during indifferent gonads pd, primoridal germ cells migrate from yolk sac, along dorsal mesentery, to genital ridge, to primary sex cords
when/where primordial germ cells migrate
week 4, along dorsal mesentery
when primordial germ cells incorporated into primary sex cords
week 6
in what structure first see cortex/medulla differentiation?
primary sex cords (weeks 5-7)
cortex/medulla degree of importance to female/male devel?
importance:
cortex-female
medulla: male
what does male phenotype require?
short arm of Y chromosome, with SRY gene
SRY gene
sex region gene on short arm of Y chromosome; produces testis determining factor (TDF) which directs development of testes
physiologically typical female development requires
2 XX chromosomes
what determines ovary production?
absence of Y chromosome
what determines primary female sexual differentiation
no production of testosterone
TDF
testis determining factor, produced by SRY gene expression on short arm of Y chromosome; determines testes development
when testes develop
week 8
seminiferous cords
coiled up, anastomosed primary sex cords
in medulla of gonad
rete testis
From primary sex cords
anastomosing network of tubules in hilum of testicle
connects to ductal system
leads to efferent ductules / mesonephric tubules
what separates seminiferous tubules
mesenchyme
seminiferous tubules- hollow or solid?
solid til puberty, then hollow
what is in wall of seminiferous tubule
interstitial cell of leydig, sertoli cells, spermatogonia
tunica albuginiea
thick structures separating surface epithelium from inner rete testis; not present in ovaries
what do interstitial cells of leydig do
secrete testosterone, lead to differentiation of mesonephric ducts and external genitalia
sertoli cells
in wall of developing testis; secretes AMH (antimullerian hormone), aka mullerian inhibiting substance, SUPPRESSES development of perimesonephric duct system > male!
what do primary sex cords become in females
rete ovarii, which regress
cortical cords
secondary sex cords in females; incorporate germ cells, become cortical cords
primordial follice surrounding oogonium formed by
cortical cords and germ cell
what do ovaries (and testes) develop from
mesonephros
how many follicles at birth of female
2 million
does woman form any oogonia after birth
no
mesonephric ducts
become male genital ducts and glands,
aka wolffian ducts
paramesonephric ducts
become female genital ducts and glands,
aka mullerian ducts
what leads to mesonephric duct development
AMH from sertoli cells + testosterone from insterstitial cells of leydig
progression of male genital duct development
mesonephric ducts > efferent ductules, ductus epididymis, ductus deferens
seminal vesicle location, function
outgrowth of ductal system
produces fluid that nourishes sperm; makes vagina more ALKALINE, helps sperm motility
ejaculatory duct connects
seminal vesicle to vas deferens
prostate develops from
endodermal outgrowths and surrounding mesenchyme from urethra; surrounds urethra
prostate function
produces fluid that comprises first part of sperm ejaculate, fluid is released into the urethra, and alkalinizes the vagina
how is prostatic fluid produced?
produced via muscular contractions of prostate
bulbourethral glands
outgrowth of spongy urethra
secretions contribute to semen
what allows female genital duct development
1) absence of testosterone > mesoneprhic ducts regress
2) absence of sertoli cells’ MIS > paramesoneprhic ducts can invaginate, develop
how paramesonephric ducts develop
invaginations on lateral mesonephroi
where is uterovaginal primordium
fused part of paramesonephric ducts, in pelvic region
becomes uterus, vagina
paramesonephric ducts location re: pelvic region
paramesonephric ducts pass caudally
fallopian tubes form where
unfused portion at top of paramesonephric ducts
what suspends ovary in ducts
mesovarian and broad ligament
what is vagina primordium, where does it form
at mullerian/sinus tubercle
forms by uterovaginal primordium growing into/meeting urogenital sinus
broad ligament forms from
fold in peritoneum
connects ovary, uterus, uterine tube
sinovaginal bulbs form from
paired endodermal outgrowths from sinus tubercle
what forms vaginal plate
fusion of sinovaginal bulbs
begins as solid > center breaks down > hymen separates lumen of cavity from urogenital sinus
what does hymen separate
lumen of sinovaginal bulbs’ fusion from cavity of urogenital sinus
location and function, urethral and paraurethral (skene’s) glands
from urethra
add lubrication to the vagina
location and function, bartholion’s glands
aka greater vestibular gland
auxiliary genital gland in females
forms from urogenital sinus
can become infected w/ gonorrhea, form abcess/cyst
homologues of outgrowths from the urethra
female: urethral and paraurethral (skene’s) glands
male: prostate
homologues of outgrowths from urogenital sinus
female: greater vestibular glands of Bartholin
male: Bulbourethral glands
lasting derivatives of mesonephric tubules
male: efferent ductules
female: none
lasting derivatives of mesonephric ducts
males: duct of epididymus, ductus deferens
females: none
lasting derivatives of paramesonephric ducts
males: none
females: uterus, tubes
lasting derivatives of urogenital sinus
males: bladder, urethra, prostate, bulbourethral glands
females: bladder, urethra, vagina, paraurethral gland, bartholins glands
vestigial structures of sinus tubercle
male: seminal colliculus
female: hymen
