Embryology of the Genital System Flashcards
what weeks is the embryo in the undifferentiated state
weeks 1-6
when does the phenotypic sexual differentiation befin
week 7
what week can male and female external genitalia be recognized
week 12
when is the phenotypic differentiation complete
week 20
primordial germ cells from ____ invade ____ and migrate to ____
endoderm of yolk sac, invade dorsal mesentery, migrate to urogenital ridges
what is the migration of the primordial germ cells guided by what?
-failure of migration = what
c-kit receptor and stem cell factor (c-kit ligand) expressed on PGCs
-failure of migration leads to gonadal dysgenesis
what is the karyotype of people with pure gonadal dysgenesis
normal set of sex chroms 46, XX or 46, XY
-may have defects of a specific gene on a chromosome
what is the name of PGD, 46, XY
swyer syndrome
what is the name of PGD, 46, XX
XX gonadal dysgenesis
in a male the ___ part of the gonad develops
in the female the __ part of the gonad develops
male = medulla female = cortex
what kind of mesoderm is gonads
intermediate, problems with gonads can also be accompanied by problems with kidneys
what does the mesonephric duct turn into in male
ductus deferens and epididymis
paramesonephric or mesonephric duct develops in female?
paramesonephric (mullerian)
what is the default fetal sex and what triggers the other sex
female is default
SRY protein made from sex determining region of Y chromosome
–SRY protein triggers male devlopment
what is the transcriptional regulator for testes differentiation and via what
SOX9 via SF1
what is the signifigance of the sertoli cells in the male
sertoli cells secrete MIH or AMH which causes the paramesonephric ducts to regress
what is campomelic dysplasia
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
sox9 is required for the formation of what cells
sertoli and leydig
what is function of leydig cells in males
formation of testosterone
what is the function of DHT
masculinization of the external genitalia and prostate
masculinization of the brain
masculiniztion of body tissues and systems
what is required for the maculinization of the internal reproductive system
testosterone
what enzyme converts testosterone into DHT (which type) and where is it made
5a-reductase II
-made in seminal vesicle, epididymis, prostate
in male the following structures become what? and what is the signal
- urogenital sinus
- genital tubercle
- labioscrotal swellings
DHT is signal
UG sinus = urethra prostate
genital tubercle = penis
labioscrotal swellings = scrotum
in female the following become what
- Urogenital sinus
- genital tubercle
- labioscrotal swellings
- UG sinus = stays open, lower vagnia vestibule
- genital tubercle = clitoris
- labioscrotal swelling, remain open, vulva
in the female what can be left over from degeneration of the mesonephric ducts
epoophoron and paroophoron
-can be called gartner’s duct
what signal is found on the X chromosome in both sexes but repressed by __ in males
-what is it upregulated by
DAX1 and repressed by SRY protein
-upregulated by WTN4
DAX1 duplicated in male prevents what
testis formation, resulting in 46XY female
cranial end of paramesonephric duct opens where and distal end goes where
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
the inferior portion of the vagina forms from what
sinovaginal bulbs
-posterior wall of UG sinus (urinary bladder and urethra)
what is mayer-rokitansky-kuster-hauser syndrome
failure of the paramesonephric ducts to develop so no uterine tubes, uterus, and malformation of upper vagina
what is the presentation of re-canalization abnormality
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
what is hematometra
from imperforate hymen, blood from menstrual cycle cannot get out
the urogenital fold becomes ____ in female
labioscrotal fold becomes ____ in female
labia minora
labia majora
steps of male external genitalia
1) enlargement of genital tubercle forms the phallus
2) urehtral folds then fuse to form penile urethra
3) labioscrotal swellings become the scrotum
cryptorchidism
undescended testes, can be unilateral or bilateral
-can be associated with increased incidence of testicular cancer
what is hypospadias and its cause
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
what are the four types of hypospadias and which is most severe
1) glandular
2) penile
3) penoscrotal
4) perineal
the closer to body the more severe
what is epispadias
and what does it often occur with
urethral meatus opens on dorsum of penis
- often occurs with bladder exstrophy
- anterior abdominal wall doesn’t close
what is klinefelter syndrome and treatment
47, XXY
- small testes, low levels testosterone
- poor developed secondary sex characteristics and gynecomastia
- risk for osteoporosis
- testosterone replacement therpay
what is turner’s syndrome
and treatment
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
pseudointersexuality of 46 XX DSD or 46 XY DSD and cause
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
classic virilizing adrenal hyperplasia
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
androgen insensitivity syndrome
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
5 a reducatase deficiency
- 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
true intersex or ovotesticular DSD
have both ovarian and testicular tissue or ovotestes
what part of the urogenital sinus is taken to make the lower part of the vagina
sinovaginal bulbs
