2-19-16-Embryology Of The Genital System (Cole)

Question 1

When can male and female external genitalia be recognized?

Answer 1

Week 12

Phenotypic differentiation complete at week 20

Question 2

Primordial germ cells from ___ of the yolk sac invade the dorsal mesentery and migrate to urogenital ridges. This migration is guided by ___ receptor and ___ ligand expressed on primordial germ cells

Answer 2

endoderm

c-kit

Stem cell factor (c-kit ligand)

Question 3

__ has a normal set of sex chromosomes (i.e., 46, XX or 46, XY), as opposed to those disorders that result from missing all or part of the 2nd sex chromosome

Answer 3

Pure gonadal dysgenesis (PGD)

Pts with PGD have a normal karyotype but may have defects of a specific gene on a chromosome

Question 4

___ is referred to as PGD, 46, XY

___ is referred to as PGD, 46, XX

Answer 4

Swyer syndrome

XX gonadal dysgenesis

Question 5

___ are aggregates of supporting cells (hormone secreting cells)

Answer 5

Primary sex cords

Question 6

In the male, this duct plays the most important role in the development of genital ducts

Answer 6

Mesonephric ducts

Question 7

In the females, this duct plays the most important role in the development of genital ducts

Answer 7

Paramesonephric ducts

Question 8

Fetal sex is encoded on the ___

Answer 8

sex-determining region of the y-chromsome (SRY)

Question 9

Synthesis of SRY protein triggers ___ development

Answer 9

Male

SRY protein is AKA testis-determining factor, TDF

Question 10

No expression of SRY triggers ___ development

Answer 10

Female

Question 11

The differentiation of bipotential gonads into testis requires ___

Answer 11

TDF (or SRY)

Question 12

Sertoli cell differentiation requires ___

Answer 12

SOX9 (testes differentiation via steroidogenic factor 1 (SF1)

Question 13

__ is required for proper sexual differentiation and chondrogenesis. A mutation in this results in a rare autosomal dominant congenital short limbed dwarfism characterized by congenital bowing of long bones associated with skeletal and extra skeletal features like hypoplastic lungs, malformations of C spine, heart and kidneys. Characteristic feature is male –> female sex reversal

Answer 13

Sox9

Question 14

A mutation in SOX9 results in ___, a rare autosomal dominant congenital short limbed dwarfism characterized by congenital bowing of long bones associated with skeletal and extra skeletal features like hypoplastic lungs, malformations of C spine, heart and kidneys. Characteristic feature is male –> female sex reversal

Answer 14

Campomelic dysplasia

Question 15

List the transcription factor/gene required for this conversion:

Differentiation of bipotential gonad into testis —> interstitial (leydig) cell differentiation

Answer 15

SOX9 (Testes differentiation via SF1)

Question 16

Testosterone is converted to Dihydrotestosterone via __ enzyme and DHT influences differentiation of external genitalia and development of the prostate

Answer 16

5-alpha-reductase-2

Question 17

Where is 5-alpha-reductase-2 made?

Answer 17

By part of the male repro tract (epididymis, seminal vesicle, prostate)

Question 18

The paramesonephric ducts regress in the differentiation into male by ___

Answer 18

AMH or MIF

Question 19

Under the influence of testosterone, the mesonephric ducts become ___

Answer 19

Ductus deferens and epididymis

Question 20

Under the influence of DHT, the urogenital sinus closes and becomes the ___

Answer 20

Urethra and prostate

Question 21

Under the influence of DHT, the genital tubercle becomes the ___

Answer 21

Penis

Question 22

Under the influence of DHT, the labioscrotal swellings become the ___

Answer 22

Scrotum

Question 23

In the development of the ovaries, primary (medullary) cords degenerate by the 10th week, cortical (secondary) cords develop and are invaded by __ cells

Answer 23

Primordial germ

Question 24

All oogonia are formed when?

Answer 24

Prenatally

Question 25

In the female, the ___ degenerate except for the epoophoron and the paroophoron found in the mesentery of the ovary

Answer 25

Mesonephric ducts

Question 26

Portions of the mesonephric duct in females may exist as __ duct

Answer 26

Gartner's

Question 27

___ leads to upregulation of DAX1

Answer 27

WTN4

Question 28

___ is found on the X chromosome in both sexes and SRY expression represses expression of this

Answer 28

DAX1

Question 29

DAX1 duplicated in a male prevents testis formation, resulting in a ___

Answer 29

46 XY, female

Question 30

___ develop during 6th week as invaginations of epithelium lateral to the mesonephros and is inhibited in the male by AMH secreted by sertoli cells

Answer 30

Paramesonephric ducts (Mullerian)

Question 31

The paired portions of the paramesonephric ducts become the ___

Answer 31

Uterine tubes

Question 32

The ___ becomes the epithelium and glands of the uterus, epithelium of the upper 1/3 of the vagina, and the muscular wall of the vagina

Answer 32

Uterovaginal primordium

Question 33

The inferior portion of the vagina forms from the posterior wall of the __

Answer 33

Urogenital sinus (urinary bladder and urethra)

Question 34

Partial or total atresia of the distal portion of both ducts (female) can result in ___

Answer 34

Cervical or vaginal atresia

Question 35

46, XY can have persistence of paramesonephric ducts if the circulating levels of __ are low or there is an abnormal response to normal ___

Answer 35

AMH AMH

Question 36

___ is the failure of the paramesonephric ducts to develop and results in missing uterine tubes, uterus, and variable malformations of the upper portion of the vagina

Answer 36

Mullerian (paramesonephric) agenesis AKA MRKH or Mayer-Rokitansky-Kuster-Hauser syndrome

Question 37

Retrograde passage of blood into the uterine tubes can cause ___, which can lead to endometriosis and adhesion formation

Answer 37

Hematosalpinx

Question 38

In both sexes, a genital tubercle develops near the ___

Answer 38

Cloacal membrane

Question 39

The ___ divides the cloacal membrane into urogenital and anal membranes

Answer 39

Urorectal septum

Question 40

The ___ divides into the urogenital sinus and rectum

Answer 40

Cloaca

Question 41

Regarding the development of male external genitalia: 1) enlargement of the genital tubercle forms the ___ 2) Urethral folds --> urethral groove, then fuse to form ___ 3) Labioscrotal swellings become the __

Answer 41

1) phallus 2) penile urethra 3) scrotum

Question 42

Regarding female development: 1) Genital tubercle elongates and bends inferiorly to become the __ 2) urethral folds become the ___; labioscrotal swellings become the ___ 3) urethra and vagina open into the ___

Answer 42

1) clitoris 2) labia minora; labia majora 3) vestibule

Question 43

__ influence the development of both the internal (paramesonephric) female duct system as well as the external genitalia

Answer 43

Estrogens

Question 44

___ is known as undescended testes

Answer 44

Cryptorchidism

Question 45

__ is incomplete fusion of the urethral folds. The urethra opens onto the ventral aspect of the penis and can result from inadequate androgen production or inadequate receptor sites for DHT

Answer 45

Hypospadias

Question 46

List the 4 types of hypospadias

Answer 46

1-glandular 2-penile 3-penoscrotal 4-perineal Slide 52 for image

Question 47

__ is when the urethral meatus opens on the dorsum of the penis and often occurs with bladder exstrophy

Answer 47

Epispadias

Question 48

___ is 47, XXY. Characterized by small testes, low levels of testosterone, poorly developed secondary sexual characteristics and gynecomastia, and elongated limbs.

Answer 48

Klinefelter Syndrome--> sex chromosome DSD Risk for osteoporosis, 20x increased risk for breast cancer Treat with testosterone replacement therapy

Question 49

___ is 45, X or 45, X/XX + 8 other variants. It is characterized by short stature, no adolescent growth spurt, broad chest, webbed neck, congenital heart disease, ovary development is abortive, and secondary sex characteristics do not develop

Answer 49

Turner's syndrome--> sex chromosome DSD Treat with GH and estrogen replacement therapy

Question 50

___ is characterized by the external genitalia of 1 sex accompanying the gonads of the other sex. It can be caused by abnormal levels of sex hormones or abnormalities in the receptors for these hormones

Answer 50

Pseudointersexuality or 46 XX DSD or 46 XY DSD Old term=pseudohermaphroditism

Question 51

In 46 XX DSD, prenatal exposure to androgens after the 12th fetal week leads only to ___, while exposure at progressively earlier stages of differentiation leads to retention of the ___

Answer 51

Clitoral hypertrophy urogenital sinus and labioscrotal fusion

Question 52

___ is AKA Female Intersex and females with severe forms of adrenal hyperplasia have ambiguous genitalia at birth due to excess adrenal androgen production in utero.

Answer 52

Classic Virilizing Adrenal Hyperplasia (46,XX,DSD)

Question 53

In female development, increased exposure to androgens may result in ___

Answer 53

Clitoral hypertrophy and/or labioscrotal fusion

Question 54

___ is an X-linked disorder in which receptors remain unresponsive to androgens. Despite normal levels of testosterone, the male fetus fails to masculinize and the external genitalia are feminine and internally, these individuals possess non-functioning undescended testes

Answer 54

Androgen Insensitivity Syndrome (AIS)-complete 46, XY, DSD At puberty, secondary female sex characteristics may appear due to estradiol from testosterone aromatization

Question 55

___ is an autosomal recessive condition resulting in the inability to convert testosterone to the more physiologically active DHT. Genetic males with this are born with ambiguous genitalia (underdevelopment of penis and scrotum or pseudovaginal perineoscrotal hypospadias)

Answer 55

5-alpha-reductase deficiency Derivatives of mesonephric duct are normal Often misdiagnosed as AIS

Question 56

___ is very rare and characterized by having both ovarian and testicular tissue or ovotestes. The causes are poorly understood, there is ambiguous external genitalia, and traditionally most are raised as female

Answer 56

True intersex or ovotesticular DSD

Question 57

WHen is the genotype of the embryo established?

Answer 57

At fertilization