Embryology of the Genital System

Question 1

what weeks is the embryo in the undifferentiated state

Answer 1

weeks 1-6

Question 2

when does the phenotypic sexual differentiation befin

Answer 2

week 7

Question 3

what week can male and female external genitalia be recognized

Answer 3

week 12

Question 4

when is the phenotypic differentiation complete

Answer 4

week 20

Question 5

primordial germ cells from ____ invade ____ and migrate to ____

Answer 5

endoderm of yolk sac, invade dorsal mesentery, migrate to urogenital ridges

Question 6

what is the migration of the primordial germ cells guided by what?
-failure of migration = what

Answer 6

c-kit receptor and stem cell factor (c-kit ligand) expressed on PGCs
-failure of migration leads to gonadal dysgenesis

Question 7

what is the karyotype of people with pure gonadal dysgenesis

Answer 7

normal set of sex chroms 46, XX or 46, XY

-may have defects of a specific gene on a chromosome

Question 8

what is the name of PGD, 46, XY

Answer 8

swyer syndrome

Question 9

what is the name of PGD, 46, XX

Answer 9

XX gonadal dysgenesis

Question 10

in a male the ___ part of the gonad develops

in the female the __ part of the gonad develops

Answer 10

male = medulla
female = cortex

Question 11

what kind of mesoderm is gonads

Answer 11

intermediate, problems with gonads can also be accompanied by problems with kidneys

Question 12

what does the mesonephric duct turn into in male

Answer 12

ductus deferens and epididymis

Question 13

paramesonephric or mesonephric duct develops in female?

Answer 13

paramesonephric (mullerian)

Question 14

what is the default fetal sex and what triggers the other sex

Answer 14

female is default
SRY protein made from sex determining region of Y chromosome
–SRY protein triggers male devlopment

Question 15

what is the transcriptional regulator for testes differentiation and via what

Answer 15

SOX9 via SF1

Question 16

what is the signifigance of the sertoli cells in the male

Answer 16

sertoli cells secrete MIH or AMH which causes the paramesonephric ducts to regress

Question 17

what is campomelic dysplasia

Answer 17

mutation in SOX9 required for proper sex diff and chondrogenesis

• congenital short limbed dwarfism with bowing of long bones
• malformations of lungs, heart, kidneys
• male to femal sex reversal
• almost always fatal

Question 18

sox9 is required for the formation of what cells

Answer 18

sertoli and leydig

Question 19

what is function of leydig cells in males

Answer 19

formation of testosterone

Question 20

what is the function of DHT

Answer 20

masculinization of the external genitalia and prostate
masculinization of the brain
masculiniztion of body tissues and systems

Question 21

what is required for the maculinization of the internal reproductive system

Answer 21

testosterone

Question 22

what enzyme converts testosterone into DHT (which type) and where is it made

Answer 22

5a-reductase II

-made in seminal vesicle, epididymis, prostate

Question 23

in male the following structures become what? and what is the signal

• urogenital sinus
• genital tubercle
• labioscrotal swellings

Answer 23

DHT is signal

UG sinus = urethra prostate
genital tubercle = penis
labioscrotal swellings = scrotum

Question 24

in female the following become what

• Urogenital sinus
• genital tubercle
• labioscrotal swellings

Answer 24

• UG sinus = stays open, lower vagnia vestibule
• genital tubercle = clitoris
• labioscrotal swelling, remain open, vulva

Question 25

in the female what can be left over from degeneration of the mesonephric ducts

Answer 25

epoophoron and paroophoron | -can be called gartner's duct

Question 26

what signal is found on the X chromosome in both sexes but repressed by __ in males -what is it upregulated by

Answer 26

DAX1 and repressed by SRY protein | -upregulated by WTN4

Question 27

DAX1 duplicated in male prevents what

Answer 27

testis formation, resulting in 46XY female

Question 28

cranial end of paramesonephric duct opens where and distal end goes where

Answer 28

cranial end = peritoneal cavity distal end = joins to form uterovaginal primordium--->epithelium and glands of the uterus, epithelium of upper 1/3 of vagina, and muscular wall of vagina

Question 29

the inferior portion of the vagina forms from what

Answer 29

sinovaginal bulbs | -posterior wall of UG sinus (urinary bladder and urethra)

Question 30

what is mayer-rokitansky-kuster-hauser syndrome

Answer 30

failure of the paramesonephric ducts to develop so no uterine tubes, uterus, and malformation of upper vagina

Question 31

what is the presentation of re-canalization abnormality

Answer 31

present with cyclic or persistent pelvic pain and primary amenorrhea -retrogade passage of blood into uterine tubes can cause hematosalimx which can lead to endometriosis and adhesion formation

Question 32

what is hematometra

Answer 32

from imperforate hymen, blood from menstrual cycle cannot get out

Question 33

the urogenital fold becomes ____ in female | labioscrotal fold becomes ____ in female

Answer 33

labia minora | labia majora

Question 34

steps of male external genitalia

Answer 34

1) enlargement of genital tubercle forms the phallus 2) urehtral folds then fuse to form penile urethra 3) labioscrotal swellings become the scrotum

Question 35

cryptorchidism

Answer 35

undescended testes, can be unilateral or bilateral | -can be associated with increased incidence of testicular cancer

Question 36

what is hypospadias and its cause

Answer 36

incomplete fusion of the urethral folds - urethra opens onto the ventral aspect of the benis - can be from inadequate androgen production or inadequate receptor sites for DHT

Question 37

what are the four types of hypospadias and which is most severe

Answer 37

1) glandular 2) penile 3) penoscrotal 4) perineal the closer to body the more severe

Question 38

what is epispadias | and what does it often occur with

Answer 38

urethral meatus opens on dorsum of penis - often occurs with bladder exstrophy - anterior abdominal wall doesn't close

Question 39

what is klinefelter syndrome and treatment

Answer 39

47, XXY - small testes, low levels testosterone - poor developed secondary sex characteristics and gynecomastia - risk for osteoporosis - testosterone replacement therpay

Question 40

what is turner's syndrome | and treatment

Answer 40

45, XO or 45, XO/46,XX - short stature, borad chest, webbed neck, CHD - secondary sex characterisitcs don't develop - GH and estrogen replacement therapy

Question 41

pseudointersexuality of 46 XX DSD or 46 XY DSD and cause

Answer 41

external genitalia of one sex accopmanies the gonads of the other sex - abnormal levels of sex hormones or receptors - prenatal exposure to androgens - the earlier the exposure, the more severe

Question 42

classic virilizing adrenal hyperplasia

Answer 42

46, XX, DSD - females with severe forms of adrenal hyperplasia have ambiguous genitalia at birth - labioscrotal folds fuse and look like scrotum - clitoral hypertrophy - ovaries are normal

Question 43

androgen insensitivity syndrome

Answer 43

46, XY, DSD - genetic male does not respond to testosterone - X linked disorder - external genitalia feminine - internally they possess non functioning undescended testes - at puberty, secondary femal sex charact may appear due to estradiol from testosterone aromatization

Question 44

5 a reducatase deficiency

Answer 44

- externally look more female - males born with ambiguous genitalia - first woman then man - at puberty, increase in testosterone and if even a slight amount of 5a reductase then start to look like a man - also a 46, XY, DSD

Question 45

true intersex or ovotesticular DSD

Answer 45

have both ovarian and testicular tissue or ovotestes

Question 46

what part of the urogenital sinus is taken to make the lower part of the vagina

Answer 46

sinovaginal bulbs