Reproductive embryology Flashcards
intermdediate (UG) mesoderm
splits to form neprogenic ridge (lateral) and genital ridge (medial)
genital ridge
in abdomen, medial to nephrogenic ridge. Forms gonads.
nephrogenic ridge
forms mesonephric (Wolfian) duct (forms ureteric bud, kidney, ureter, urinary bladder, male internal reproductive organs) and paramesonephric (Mullerian) duct (female internal reproductive organs)
AMH
produced by sertoli cells, suppresses paramesonephric ducts
Testosterone
produced by Leydig cells in response to LH or hCG. Stimulates mesonephric duct structures (efferent ductules, epididymis, vas deferens, seminal vesicles) and male secondary sex characteristics
DHT
converted from testosterone in peripheral tissue by 5alpha-reductase-2. Promotes development of penis, scrotum, and prostate.
hypospadia
penile urethra open on ventral surface of penis. Cause: urethral folds fail to fuse on ventral surface of penis.
epispadias
penile urethra opens on dorsal surface of penis. Unknown cause.
indirect hernia
failure of processus vaginalis to close around deep inguinal ring.
cortex of indifferent gonad
forms ovary
medulla of indifferent gonad
forms testis
uterus arcuatus
slight indentation in fundus. Cause: lack of fusion of paramesonephric ducts
uterus bicornis bicolis
2 uterine bodies, 2 cervixes. Cause: lack of fusion of paramesonephric ducts.
uterus didelphis with double vagina
2 uterine bodies, 2 vaginas. Cause: complete lack of fusion of paramesonephric duct.
uterus bicornis unicollis
2 uterine bodies, one cervix. Cause: one paramesonephric duct fails to make contact with the other.
uterus unicornis
one uterine body, one cervix, one uterine tube. Cause: one paramesonephric duct regesses.
Klinefelter syndrome
“girly man syndrome” 47, XXY, male. Testes form, but infertile. At puberty: low testosterone, high estrogen. Secondary female characteristics.
Turner syndrome
45, XO, female. No ovaries, streak gonads, cancer risk. Rest of female internal and external genitalia form normally. At puberty: low estrogen, lack of secondary sex characteristics.
Swyer syndrome
46, XY, female. Point mutation in SRY gene->defective TDF protein. Very similar presentation to 45, XO (Turner’s syndrome). No ovaries, streak gonads, rest of female external and internal genitalia form normally.
True hermaphroditism
most have 46, XX genotype, likely translocated Y chromosome. Development of ovotestes. Internal genitalia most often female, ambiguous external genitalia.
Female pseudohermaphroditism
46, XX. Congenital adrenal hyperplasia->excess testosterone. Ovaries form due to lack of TDF. Internal genitalia usually female. Masculinization of external genitalia.
Male pseudohermaphroditism
46, XY. Testes form (normal SRY). Insufficient androgen and AMH (hypogonadism). External and internal genitalia female (due to absence of testosterone and AMH).
Androgen insensitivity syndrome
46, XY. Female phenotype. Testes form (normal SRY). AMH and testosterone production is normal. Lack of androgen receptor expression on reproductive tissues. Mesonephric AND paramesonephric ducts degenerates (testosterone insensitivity, AMH production)->no female internal genitalia. Female external genitalia form.
