Criteria for Determining Sex

Question 1

What does the SRY gene induce?

Answer 1

Testes formation

Question 2

What hormones do the testes produce?

Answer 2

Anti-Mullerian hormone and testosterone

Question 3

What does the SRY product trigger?

Answer 3

Sertoli cell fate

Question 4

What is the Sertoli cell fate triggered by?

Answer 4

Product sry

Question 5

What develops instead of a Sertoli cell if SRY is absent?

Answer 5

A follicle cell

Question 6

What develops from Sertoli cells?

Answer 6

Sperm cells

Question 7

How does sry protein exhibit transcriptional control?

Answer 7

Sry protein contains an HMG box-type of DNA binding domains which binds to the minor grooves of DNA altering its configuration

Question 8

Which gene is involved in long-term maintenance of the sex pathway thats being determined by SRY?

Answer 8

SOX9

Question 9

After SRY is activated in males and females what happens to SOX9 levels?

Answer 9

Increases in males

Decreases in femaes

Question 10

What can mutations of SOX9 cause?

Answer 10

Male-female sex reversal

Question 11

If which enzyme is absent, can sry not be expressed so XY individual would develop as females phenotypically?

Answer 11

Jmjd1a

Question 12

What does the Jmjd1a do?

Answer 12

Allow sry to be expressed so XY individuals develop as males phenotypically

Question 13

Criteria for Sex Determination: What are the germ cells in males?

Answer 13

Sperm

Question 14

Criteria for Sex Determination: What are the germ cells in females?

Answer 14

Egg/oocyte

Question 15

Criteria for Sex Determination: What are the supporting cells in males?

Answer 15

Sertoli cells

Question 16

Criteria for Sex Determination: What are the supporting cells in females?

Answer 16

Follicle cells

Question 17

Criteria for Sex Determination: What are the steroidal cells in males?

Answer 17

Leydig cells

Question 18

Criteria for Sex Determination: What are the steroidal cells in females?

Answer 18

Theca cell

Question 19

Criteria for Sex Determination: What is the connective tissue in males?

Answer 19

Testicular cords/myoid cells

Question 20

Criteria for Sex Determination: What is the connective tissue in females?

Answer 20

Stroma cells

Question 21

How can autosomal genes have a role in sexual differentiation?

Answer 21

Autosomal genes may produce necessary enzymes, carriers etc. to manufacture supporting systems

Question 22

Autosomal genes in sexual differentiation: Deficiency of 5 alpha reductase

Answer 22

• Converts testosterone to more active 5 dihydroxytestosterone
  If lacking, then male genitalia do not differentiate properly

Question 23

Give examples of when autosomal genes have a role in sexual differentiation

Answer 23

• Deficiency of 5 alpha reductase

- Testicular feminisation syndrome

Question 24

Autosomal genes in sexual differentiation: Testicular feminisation syndrome

Answer 24

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

Question 25

What is the karyotype in testicular feminisation syndrome?

Answer 25

46/XY

Question 26

What is the genotype and phenotype displayed in testicular feminisation syndrome?

Answer 26

Normale male genotype but generally underdeveloped female genitalia

Question 27

Which ducts degenerate in males?

Answer 27

Paramesonephric (Mullerian) ducts

Question 28

Which ducts degenerate in females?

Answer 28

Mesonephric (Wolffian) ducts

Question 29

At 10 weeks, Mullerian (paramesonephric) ducts degenerate in ________

Answer 29

Males

Question 30

At 10 weeks, Wolffian (mesonephric) ducts degenerate in ________

Answer 30

Females

Question 31

What are the two phases in testes descent?

Answer 31

1. Transabdominal

2. Ingino-scrotal

Question 32

What is the ingino-scrotal phase of testes descent dependent on?

Answer 32

Testosterone

Question 33

What is hydrospadosis?

Answer 33

Urethra opens on ventral side of the penis

Question 34

What is cryptorchidism?

Answer 34

When testes don’t descend into the scrotal sacks