Dev. of Reproductive Flashcards
What do the somatic support cells become in the male and female?
- Male: sertoli
- Femae: follicle
Where do the genital ducts form?
In the intermediate mesoderm of the urogenital ridge
What is the mesonephric duct, and what are its derivatives?
- Part of early kidney development
- Epididymis, vas deferens, seminal vesicles, ejaculatory duct
What are the derivatives of the paramesonephric duct?
Oviduct, uterus, upper vagina
What happens with the SRY gene, when is it active, where is it found?
Development becomes male
- only active from days 41-52 and expressed in the somatic support cells
- Upregulates testis specific genes
What cells help organize seminiferous tubules?
Sertoli cells that surround primordial germ cells
What stimulates the production of anti mullerian hormone? What does AMH cause?
- SRY gene stimulates the TF Sox9 which stimulates AMH causing the regression of the paramesonehpric duct btw weeks 8-10
What drives the mesonephric ducts to form their derivitives and what are they?
- Leydig cells producing testosterone
- Forms efferent ductules
- Epididymis
- Vas deferens
- Seminal vesicles
In the male when the paramesonephric duct regresses what is left behind?
- Utricle
- Appendix epididymis
Describe Fetal Leydig cells.
- They’re only present in fetal life, they regress in fetal/early postnatal life
- Produce testosterone around weeks 8-12 driven by hCG from the placenta to form the mesonephric duct
What does 5-a hydroxylase do?
- Converts testosterone into dihydrotestosterone which will cause:
- Genital tubercle to develop into the penis
- Genital swellings to develop into scrotum
- Urethral epithelium to develop into prostate
What do adult leydig cells do?
responsible for androgen production causing initiation of spermatogenesis at puberty and masculinization of brain and sexual behavior
Where does the seminal vesicle and vas deferens come from?
Buds from mesonephric duct in the intermediate mesoderm of the urogenital ridge
Where does the prostate gland bud from?
Endoderm of urogenital sinus in region of the pelvic urethra around week 10
Where do bulbourethral glands come from?
Endodermal buds
What is the genital tubercle?
- ectodermal covered mesodermal swelling at ventral and cranial end of phallic portion of urogenital plate
What is the glans plate?
remnanats of cloacal membrane at the ventral end of the urogenital plate and adjacent genital tubercle
What is the urogenital plate?
Rupture of the cloacal membrane opening the phallic portion of the urogenital sinus to exterior forming endodermally lined platej
How does DHT impact labioscrotal swellings and genital tubercle?
It drives the lengthening and growth of genital tubercle and fusion of the labioscrotal swellings to form scrotum
When does the urethra close?
week 14
What is hypospadias?
Most common birth defect in males after cryptorchidism, failure of the urethral fold to close fully
What is epispadias
Genital tubercle forms inferior to glans plate and urethra opens superior to penis, rare
In the absence of SRY gene, what drives ovarian development?
WNT-4 and FOXL2
- Constant expression of FOXL2 suppresses SOX-9 development which maintains the female gonad development
In absense of SRY what do primordial germ ccells differentiate into and what about the somatic support cells
Oogonia which proliferate and differentiate into oocytes and follicle cells surrounds surround oocytes blocking meiosis I
In the absence of sertoli and leydig cells in women, what occurs?
NO AMH is produced so the paramesonephric ducts are retained and mesonephric duct system is lost
What happens during weeks 9-10 in uterus formation?
Fusioin of the inferior paramesonephric ducts form the uterus and uterine tubes are unfused superior portion of the paramesonephric ducts
How does the vagina form?
Forms from lengthening of solid sinuvaginal bulbs which come from endoderm, and it eventually canalizes
What does the vaginal fornix form from?
Fussed paramesonephric ducts (mesoderm)
What causes vaginal agenesis?
failed sinovaginal bulb development &/or canalization
In the female what is the phallic segment of the urogenital sinus made of?
- Urogenital plate
- Glans plate
- Genital tubercle
glans clitoris forms from what?
genital tubercle
How does the broad ligament form??
- Midline fusion of paramesonephric ductrs brings the urogenital ridge within the pelvic cavity and its covered with peritoneum
- When the uterus is formed the tissue thins forming double fold of peritoneum supporting the uterus and ovary
Round ligament of ovary connecting it to uterus develops from ___.
Superior gubernaculum
Round ligament of uterus connecting uterus to labia majora forms from ____.
Inferior gubernaculum
Patient has genotype of 46,XY and has testis but phenotype is female. What could it be?
Could be:
- Inadequate production of testosterone
- Androgen insensivity syndrome
- 5-alpha reductase deficiency (cant go from testosterone to DHT)
- Mutations in AMH hormone or receptor
What is androgen insensitivity syndrome in males?
- X linked recessive
- Male may have testis but no spermatogenesis and testosterone levels may be high due to lack of NFB bc body can’t detect testesterone
- At puberty testosterone is metabolized to estradiol initiating female seocondary characteristics but patients exhibit amenorrhea
- Testes usually found in inguinal or labial regions
- Has increased risk of tumor formation in gonads
What is 5-alpha reductase deficiency in males?
- XY 46 genotype
- Auto recessive
- Normal testis and duct system, could make AMH and testosterone
- Underdeveloped male external genitalia due to lack of DHT
- depending on level of deficiency patient can exhibit external female phenotype
Female congenital adrenal hyperplasia?
- Fetus produces excess androgens resulting in masculinizaton of female external genitalia
- could result in labia fusing
- Congenital adrenal hyperplasia is most common cause of female sexual ambiguity
- deficiency in 21 hydroxylase
