197/198/199 - UG Development, Congenital Anomalies, Sexual Differentiation Flashcards
C - congenital adrenal hyperplasia due to 21-alpha-hydroxylase deficiency
- Testicular DSD will have male external genitalia
- In partial androgen insensitivity syndrome, gonads are present; will not have XX karyotype
Describe the presentation of posterior urethral valves
- Prenatal
- Bilateral hydronephrosis
- Thick-walled bladder
- Oligohydraminos
- Post-natal
- UTI
- Renal insufficiency
- Pulmonary insufficiency
- Incontinence
- Poor urinary stream
What is the role of sertoli cells in sexual differentiation?
Produce AMH -> regression of mullerian ducts
E - posterior urethral valves
Which primordial tissue gives rise to the kidney nephrons?
Metanephric mesoderm
Which indifferent-stage structure gives rise to the prostate and prostatic urethra in 46, XY individuals?
What is the corresponding structure in 46, XX individuals?
Urogenital sinus
Lower vagina and urethra in 46, XX individuals
Why is testosterone elevated in 21-alpha-hydroxylase deficiency?
Normally, 21-alpha-hydroxylase turns 17-OH-progesterone into 11-deoxycortisone
Without 21-alpha-hydroxylase, 17-OH-progesterone is shunted towards the testosteone synthesis pathway -> increaesed testosterone
In females, the secondary sex cords will give rise to which adult structure?
What kind of cells is this structure composed of?
Ovarian follicles
Ovum surrounded by epithelium of granulosa cells
Note: Primary sex cords persist as nonfunctional/vestigial rete ovarii
What is the most common congenital cystic kidney disease?
Multicystic dysplastic kidney
Where in the male is junction of the urethra derived from the urogenital sinus and surface ectoderm?
A. Urinary bladder and prostatic urethra
B. Beginning of the penile urethra
C. Proximal and distal halves of the penile urethra
D. Penile urethra and navicular fossa in the glans
E. Penile urethra and distal epidermis of the glans
D. Penile urethra and navicular fossa in the glans
Where in the adult female is the junction of derivatives of the paramesonephric ducts and urogenital sinus?
A. Uterine tubes and uterus
B. Uterine fundus and cervix
C. Uterus and vagina
D. Middle of the vagina
E. Vagina and vestibule
D. Middle of the vagina
Describe the internal and external genitalia that result from complete androgen insensitivity syndrome in a 46, XY individual
Testosterone present, but receptors non-functional
- Internal
- Testes, often undescended
- AMH secreted -> no uterus or Mullerian structures
- External
- No testosterone action -> female external genitalia
- Testosterone aromatized to estrogen -> breast development
- Often presents in a female-presenting individual with primary amenorrhea*
- 5-alpha-reductase deficiency will have female external genitalia but then development of male structures in puberty 2/2 increased testosterone*
In a ureteral duplication:
- Which ureter is more likely to develop obstruction?
- Which is more likely to develop reflux?
- Obstruction: Ureter from upper moiety
- Inserts inferiorly and medially in the bladder
- Also more likely to have ectopic ureter, ureterocele
- Reflux: Ureter from lower moiety
- Inserts laterally and superiorly in the bladder
- In general, this is more anatomically normal
Which 2 embryonic primordia form the male urethra?
- Urogenital sinus (endoderm) -> proximal majority
- Navicular fossa (ectoderm) -> distal end
Failure of fustion = hypospadias; opening on the ventral surface
A woman is infertile because of an absence of ova. Where might primordial ova have failed to differentiate?
A. Genital ridge mesoderm
B. Primary sex cords
C. Hindgut endoderm
D. Secondary sex cords
E. Paramesonephric duct
C. Hindgut endoderm
- Primordial germ cells orginate in the hindgut, then migrate to the genital ridge*
- Sex cords give rise to the epithelial components of the gonads only (Leydig & Sertoli or Granulosa/Theca)*
What is most common cause of ureteropelvic junction obstruction that is…
- Intrinsic:
- Extrinsic:
- Intrinsic: Aperistaltic segment
- Most common overall cause of UPJ
- Extrinsic: Crossing vessels
Which cells produce anti-mullerian hormone?
Sertoli cells
No gonads/streak gonad -> no Sertoli cells or Leydig cells -> no AMH or testosterone (respectively) -> Mullerian structures persist, no androgen effect on external genitalia
Fetal hydronephrosis 2/2 urinary tract dilation is detected on prenatal ultrasound
How should this be managed?
Observation
50-80% of antenatal hydronephrosis will spontaneously resolve; does not necessarily represent a specific pathology
What are the adult derivatives of the labioscrotal folds in…
- Males:
- Females:
- Males: Scrotum
- Females: Labia majora
C - complete androgen insensitivity syndrome
- 5-alpha reductase = no breast development
- Mixed gonadal dysgenesis is similar, but will not have symmetric inguinal masses (testes)
- 21-hydroxylase deficiency would present much earlier
- Salt wasting, hyperkalemia, failure to thrive soon after birth
Describe the internal and external genitalia that result from 5-alpha-reductase deficiency in a 46, XY individual
- Internal
- Testes, synthesize AMH -> no mullerian structures
- Also synthesize testosterone
- External
- Cannot convert testosterone to DHT -> Variable external genitalia
- Depends on amount of DHT that is produced
- More DHT -> more development of male structures
Male structures will often begin to develop during puberty due to increased testosterone
Where are sperm synthesized?
Where are they stored?
Synthesis: Testes
Storage: Epididymis
What embryonic structure gives rise to the ureter?
Mesonephric duct -> Ureteric bud
Keys is that the ureteric bud comes from the mesonephric duct, not the urogenital sinus