Criteria for Determining Sex Flashcards
What does the SRY gene induce?
Testes formation
What hormones do the testes produce?
Anti-Mullerian hormone and testosterone
What does the SRY product trigger?
Sertoli cell fate
What is the Sertoli cell fate triggered by?
Product sry
What develops instead of a Sertoli cell if SRY is absent?
A follicle cell
What develops from Sertoli cells?
Sperm cells
How does sry protein exhibit transcriptional control?
Sry protein contains an HMG box-type of DNA binding domains which binds to the minor grooves of DNA altering its configuration
Which gene is involved in long-term maintenance of the sex pathway thats being determined by SRY?
SOX9
After SRY is activated in males and females what happens to SOX9 levels?
Increases in males
Decreases in femaes
What can mutations of SOX9 cause?
Male-female sex reversal
If which enzyme is absent, can sry not be expressed so XY individual would develop as females phenotypically?
Jmjd1a
What does the Jmjd1a do?
Allow sry to be expressed so XY individuals develop as males phenotypically
Criteria for Sex Determination: What are the germ cells in males?
Sperm
Criteria for Sex Determination: What are the germ cells in females?
Egg/oocyte
Criteria for Sex Determination: What are the supporting cells in males?
Sertoli cells
Criteria for Sex Determination: What are the supporting cells in females?
Follicle cells
Criteria for Sex Determination: What are the steroidal cells in males?
Leydig cells
Criteria for Sex Determination: What are the steroidal cells in females?
Theca cell
Criteria for Sex Determination: What is the connective tissue in males?
Testicular cords/myoid cells
Criteria for Sex Determination: What is the connective tissue in females?
Stroma cells
How can autosomal genes have a role in sexual differentiation?
Autosomal genes may produce necessary enzymes, carriers etc. to manufacture supporting systems
Autosomal genes in sexual differentiation: Deficiency of 5 alpha reductase
- Converts testosterone to more active 5 dihydroxytestosterone
If lacking, then male genitalia do not differentiate properly
Give examples of when autosomal genes have a role in sexual differentiation
- Deficiency of 5 alpha reductase
- Testicular feminisation syndrome
Autosomal genes in sexual differentiation: Testicular feminisation syndrome
Low levels of cytosol carrier protein for testosterone prevents actions
Female phenotype due to unopposed action of small amounts of oestrogen from testes
- testosterone present but effect not induced
What is the karyotype in testicular feminisation syndrome?
46/XY
What is the genotype and phenotype displayed in testicular feminisation syndrome?
Normale male genotype but generally underdeveloped female genitalia
Which ducts degenerate in males?
Paramesonephric (Mullerian) ducts
Which ducts degenerate in females?
Mesonephric (Wolffian) ducts
At 10 weeks, Mullerian (paramesonephric) ducts degenerate in ________
Males
At 10 weeks, Wolffian (mesonephric) ducts degenerate in ________
Females
What are the two phases in testes descent?
- Transabdominal
2. Ingino-scrotal
What is the ingino-scrotal phase of testes descent dependent on?
Testosterone
What is hydrospadosis?
Urethra opens on ventral side of the penis
What is cryptorchidism?
When testes don’t descend into the scrotal sacks
