Urogenital Development (6) Flashcards
(33 cards)
kidney development
- pronephroi (week 4)
- mesonephroi (week 4) aka embryological kidney for 4 weeks
- metanephroi (dev week 5, function by 9) aka adult kidneys
mesonephroi ducts
drain the mesonephroi but after degeneration (12) ducts remain and develop in males
metanephroi development
ureteric bud + metanephrogenic blastema
initial growth from bud
bud is outgrowth of mesonephric duct
adult derivatives
other kidney parts
stalk > ureter
cranial bud > collecting tubules > major and minor callices
fetal kidney has lobes dissapear in 1st year
renal agenesis
kidneys not develop so either unilateral or bilateral
if bilateral assoc w/ oligohydramnios and death
oppo of polyhydramnios, little/no amniotic fluid
horseshoe kidney
fusion at the poles so kidneys can’t rise
higher in males and females with turner’s syndrome
ectopic ureter
ureter in the ductus deferens/seminal gland/urethra/vagina = incontinence
urogenital sinus parts
- vesical- forms bladder and allantois
- pelvic- forms urethra
-males = membranous and prostatic only
-females = entire - phallic- primordium of penis or clitoris and spongy urethra in males
glans penis from ectoderm instead of endo
bladder development
- bladder and allantois initially continous
- allantois constricts > urachus
- mesonephric ducts incorporated into dorsal wall of bladder
bladder locations
birth-6 yr = abdominal organ
6-puberty = greater pelvis
adult = lesser pelvis
urachal sinus
allantois closure problems
allantois doesn’t close fully so urine flow out of umbilicus
urachal fistula
allantois closure problems
allantois doesn’t close at all so free flow out of umbilicus
urachal cyst
allantois closure problems
allantois closes but urine becomes trapped in a pouch
gonad development
- primordial germ cells from yolk sac
- undifferentiated until week 6-7 with cortex and medulla
- cortex > ovary (medulla regress) and medulla > testis (cortex regress)
testes development
- XY genotype
1. SRY gene on Y starts testicular dev by **turning off **Wnt4, Foxl3, Fst, Rspo1 = inhibit ovarian dev
2. hormones produced for functional dev
-testosterone, DHT, AMH
3. testes cordoned off from mesonephros by thick tunica albuginea
4. AMH inhibits paramesonephric
5. seminiferous tubules produce sperm @ puberty
ovary development
XX genotype
1. Wnt4, Foxl2, Fst, Rspo1 genes make functional
2. must have two X for functional dev
3. separated from mesonephros by thin tunica albuginea
4. no oogonia postnatally
no hormones needed
genital ducts
males
testosterone stimulates mesonephric ducts > ductus deferens, seminal vesicles, ejac ducts
AMH degenerates paramesonephric duct
prostate and bulbourethral glands outgrowth of urethra (urogenital sinus)
genital ducts
females
no testosterone = mesonephric dissapear
no AMH = paramesonephric ducts dev
estrogens from mother stim dev of uterine tubes + uterus + superior vagina from paramesonephric
greater vestibular glands and paraurethral glands form from urogenital sinus
external genitalia
male
induced by testosterone
phallus enlarges/elongates = penis and encloses spongy urethra
labioscrotal swellings fuse = scrotum
external genitalia
female
NOT hormonally induced
phallus shrinks = clitoris
urethral folds separate = labia minora
labioscrotal swellings stay separated = majora
ovotesticular DSD
non functional sex organs
ambiguous external
have both testicular and ovarian tissue
XX DSD
female fetus exposed to excessive androgens (steroids) = functional ovaries but masculine external
XY DSD
inadequate testosterone and AMH by fetal testes = variable external
androgen insensitivity syndrome
aka testicular feminization syndrome
XY genotype resistant to testosterone
typical female appearance but vagina ends in blind pouch
testes present and ovaries absent, no menses
testes removed for cancer prevention
