Urogenital system I & II Flashcards
What are the three sets of kidney systems?
pronephros, mesonephros, and metanephros
Mesonephric kidney
functional between 5-10th week
mesonephric tubules
in males some persist as efferent ductules of testes
mesonephric duct
in males - persist as ductus (vas) deferens and epididymis
Metanephric kidney
forms adult functional kidneys, begins functioning at end of 9th week, develops early 5th week
Which two structures does the metanephric kidney develop from?
ureteric bud and metanephric mesoderm
Ureteric bud forms
ureter, renal pelvis; branches within metanephric mesoderm forms: major & minor calyces, collecting ducts (tubules)
Collecting ducts induce metanephric mesoderm to form
metanephric vesicles and metanephric tubules
Metanephric vesicles and metanephric tubules develop into
bowmans’ capsule, proximal convoluted tubule, descending and ascending limbs of henle’s loop, distal convoluted tubule
All of the structures that come from the metanephric mesoderm create…
the urine-forming part of the kidney
Renal corpuscle
bowman’s capsule + glomerulus
ascent of kidneys
kidneys initially develop in pelvis, ascent to suprarenal glands by 9th week, blood supply changes
polar renal artery
compresses the ureter and impairs flow of urine, causes swelling
ectopic kidney
kidney located in wrong spot due to failure to ascend to correct position
horseshoe kidney
when the two kidneys fuse together and gets hooked on the inferior mesenteric artery
Ureteric bud malformations
duplicated ureters (partial or complete) - when there are two duplicated ureters, one will be normal and the other could join at inappropriate spot
supernumerary kidneys - when there are extra kidneys
Renal agenesis
results from lack of formation of ureteric bud or disrupted interaction with metanephric mesoderm. Unilateral - compatible with life & bilateral - incompatible with life
development of suprarenal (adrenal) glands
the fetal adrenal cortex develops within mesoderm of the urogenital ridge, neural crest migrate to the adrenal cortex to form adrenal medulla, the cortex engulfs and ultimately encapsulates the entire medulla
formation of bladder and urethra
forms from cloaca and urogenital sinus; from endoderm and splanchnic mesoderm
three regions of urogenital sinus
- Vesicle part - becomes bladder
- Pelvic part - becomes urethra in female and part of urethra in male
- Phallic part - becomes penile urethra in male and forms space vestibula of vagina in females
allantois
becomes urachus, forms median umbilical ligament in humans
trigone of bladder
incorporation of mesonephric ducts into posterior bladder
urachal fistula and cysts
if uracha fails to become fibrous cord, could cause fistula or cyst
exotrophy of the bladder
ventral body wall does not form correctly, mesoderm migration is not sufficient and baby’s can be born with an open bladder.
anorectal malformations
urorectal fistula - incomplete partition of the cloaca often occurs with imperforate anus
Most of the urogenital system develops from…
intermediate mesoderm
What do the kidneys develop from?
Intermediate mesoderm
What do the ureters develop from?
Intermediate mesoderm
What does the bladder develop from?
Urogenital sinus (splanchnic mesoderm, endoderm
What does the urethra develop from?
Urogenital sinus (endoderm, splanchnic mesoderm, and ectoderm for males)
Pronephric kidney
rudimentary and transitory, the pronephric tubules degenerate and the pronephric duct contributes to the mesonephric duct
Nephron is made up of what structures
bowman’s capsule, glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tubule
Uriniferous tubule
nephron + collecting duct
Polycystic kidney disease
autosomal dominant or recessive, also can be acquired from dialysis, cysts form in segments of nephron, causes renal failure in childhood (AR) or in adulthood (AD)
which embryonic kidney gives rise to the adult kidney?
metanephric kidney
The urine collecting portion of the kidney is derived from the
uteric bud
Prior to the 7th week of development, male and female embryos…
are identical in sex
Gonads develop from
urogenital ridge
when do primordial germ cells begin to migrate
6th week
How do gonads differentiate into male and female gonads?
epithelium of gonadal ridge proliferates to form primitive sex cords and primordial germ cells migrate from yolk sac to developing gland.
XY differentiation at 7 weeks
Testis determining factor (TDF) present, primitive sex cords become seminiferous (medullary) cords, rete testis, tunica albuginea, leydig cells start producing testosterone, sertoli cells produce mullerian inhibiting factor (MIF), and spermatogonia takes place
XX differentiation at 12 weeks
No testis determining factor (TDF), cortical cords, primordial follicles, no testosterone, no MIF, oogonia
Mesonephric duct derivatives
efferent ductules, epididymis, vas deferens, seminal vesicles, ejaculatory ducts
Paramesonephric duct derivatives
fallopian tubes, uterus, upper 1/3rd of vagina
which tissues give rise to prostate?
urogenital sinus endoderm and associated mesenchyme
Formation of uterus and vagina
contact of paramesonephric duct to pelvic portion of UG sinus induces sinovaginal bulbs (endoderm), solid vaginal plate becomes canalized by 5th month, hymen separates vagina from UG sinus
Upper 1/3rd of vagina is from
paramesonephric duct (mesoderm)
Lower 2/3rd of vagina is from
urogenital sinus (endoderm)
Epithelium of spongy urethra comes from?
- Endoderm from phallic portion of urogenital sinus
- Surface ectoderm forms glandular plate that canalizes to form distal urethra
Hypospadias
external urethral orifice on ventral side of penis - results from incomplete fusion of urogenital folds or incomplete canalization of glandular plate
Epispadias
urethral orifice and tissue is on dorsal side of penis. Associated with exotrophy of bladder.
Female pseudohermaphrodism, 46, XX - congenital adrenal hyperplasia
excessive production of androgens results in masculinzation of external genitalia
Male pseudohermaphrodite
XY genotype, testis are rudimentary to normal, feminization of external genitalia, reduced production of androgens and mullerian inhibiting factor
Androgen insensitivity syndrome (46, XY)
a defect in the androgen receptor mechanism leads to resistance to testosterone at the cellular level
Turner syndrome 45, X
webbed neck, broad chest, widely spaced nipples, short stature, gonadal dysgenesis
Descent of testes
- Gubernaculum extends from testes to floor of scrotum and assists in descent of testes from posterior abdominal wall to scrotum
- Processus vaginalis - evagination of peritoneum that passes through inguinal canal. Follows course of gubernaculum into scrotum.
Cryptorchidism
The most common genital problem encountered by pediatrics, seen in 3-4% of full term male births, up to 30% in preterm male births; most spontaneously descent by the 1st year
Indirect inguinal hernia
processus vaginalis remains in open communication with peritoneal cavity
Hydrocele
fluid accumulation in tunica vaginalis
A bicornuate uterus was diagnosed in a 20 year old patient who had been referred to a gynecologist on account of several miscarriages. This uterine anomaly results from:
a defect of the paramesonephric ducts
