SM_199b: Sexual Differentiation: Normal and Abnormal Flashcards
Describe sex development
Sex development
- Chromosomal sex
- Sex differentiation via ovary-determining genes or testis-determining genes
- Gonadal sex
- Sexual differentiation via gonadal steroids
- Phenotypic sex
Chromosomal sex is developed via ____
Chromosomal sex is developed via meiosis
(nondisjunction can occur)
Describe development of gonadal sex
Gonadal sex development
- First few weeks: gonad starts to develop primordial germ cells in yolk sac
- 5-6th week: urogenital ridge develops further and germ cells migrate from hindgut to genital ridge
- Differentiation occurs by 8 weeks of differentiation
- Ovary develops later after week 10 and requires presence of germ cells
____ is necessary for development of gonads and adrenal glands
SF1 is necessary for development of gonads and adrenal glands
____ and ____ must act for testis formation
SRY and SOX9 must act for testis formation
___ must be suppressed and ___ active for ovarian development
SOX9 must be suppressed and WNT4 active for ovarian development
Describe development of reproductive tract
Reproductive development tract
Sertoil cells secrete ____ to promote Mullerian regression
Sertoil cells secrete AMH to promote Mullerian regression
Leydig cells secrete ____ and ____ to promote male sexual differentation
Leydig cells secrete testosterone and DHT to promote male sexual differentation
Describe AMH (anti-mullerian hormone)
AMH (anti-mullerian hormone)
- Produced by Sertoil cells
- Regulated by SF1 and SOX9
- Causes regression of mullerian structures
- Paracrine effects: AMH from testis causes regression on ipsilateral side
- Described human mutations of AMH are in 46 XY individuals with persistent mullerian duct syndrome
5 alpha reductase 2 mediates ____ and is required for ____
5 alpha reductase 2 mediates conversion of testosterone to dihydrotestosterone and is required for masculinization of external genitalia
Describe phenotypic sex development
Phenotypic sex development
Compare and contrast 46 XY and 46 XX development
46 XY and 46 XX development
Sex development and gender development are ____
Sex development and gender development are different
Disorders of sexual development can present at ___
Disorders of sexual development can present at any time