Development/Embryology Flashcards
What week are male and female external genitalia recognizable?
12
What week is phenotypic differentiation complete?
20
Where do primordial germ cells come from?
Endoderm of the yolk sac
What is expressed on Primordial germ cells that guides their migration to the urogenital ridge?
C-kit receptor and stem cell factor (C-kit ligand)
What is it called when there is a failure of PGCs to reach the genital ridge?
Gonadal dysgenesis
What non primary kidney duct do males keep and what does it become?
Mesonephric (Wolff) duct - ductus deferens
What non primary kidney duct do females keep?
Paramesonephric (Muller) duct
What do Sertoli cells secrete to get rid of paramesonephric ducts?
Mullerian inhibitory Substance (Anti Mullerian hormone)
What cells in the testes make testosterone and also make sure the mesonephric duct becomes the ductus deferens?
Leydig cells
In order for the Sertoli cells to make sure the paramesonephric duct regresses, they first have to differentiate. This is under the control of what?
SOX9 and SF1
Mutation in SOX9 causing short limbed dwarfism characterized by congenital bowing of long bones associated with skeletal and extra skeletal features like hypoplastic lungs, malformations of cervical spine, heart, and kidneys. Also male to female sex reversal
Campomelic dysplasia
What has an important role in masculinization of external genitalia and prostate
DHT
5-alpha-reductase has two isozymes. Which one is made by parts of the male reproductive tract?
5-alpha-reductase II
What disorder has genetically male but they look female? (Intersexuality)
5 ARD
In the development of the ovaries, what part of the gonads degenerate and what develops?
Medulla degenerates and cortex develops
Opposite in male gonads
When the mesonephric duct doesn’t degenerate in a female, they are found in the mesentery of the ovary (broad ligament) and are called what?
Epoophoron and paroophoron (or Gartner’s duct)
What is the gene that is found on the X chromosome but it repressed by the SRY in males and is responsible for controlling ovarian development?
DAX1
What does DAX1 do?
Blocks SOX9 and AMH expression
What upregulates DAX1?
WTN4
What fuse together to form the uterus?
The 2 paramesonephric ducts
Failure of the paramesonephric ducts to develop, resulting in missing uterine tubes, uterus, and variable malformations of the upper portion of the vagina is called what?
Mullerian (paramesonephric) agenesis or MRKH - Mayer-Rokitansky - Kuster- Hauser Syndrome
Undescended Testes?
Cryptorchidism
Incomplete fusion of urethral folds causing urethra to open onto the ventral aspect of the penis?
Hypospadias
Urethral meat us opens on the Dorsey of the penis and often occurs with bladder exstrophy
Epispadias
47 XXY, small testes, low levels of testosterone. Poorly developed secondary sexual characteristic and gynoxomastia (breast development). Elongated limbs.
Klinefelter syndrome
45 X or 45X/46XX. Short stature, no adolescent growth spurt, broad chest, webbed neck, congenital heart disease. Ovary development is abortive.
Turner’s syndrome
46XX or 46 XY. External genitalia of one sex accompanies gonads of the other sex
Pseudo intersexuality
What week does phenotypic sexual differentiation begin?
7
