Lecture 2- Sex Differences

Question 1

What are the three factors determining development of male sex organs

Answer 1

• Testis- determining factor
• Anti-Mullerian hormone
• Androgens: Testosterone and Dihydrotestosterone

Question 2

What is XY sex reversal?

Answer 2

Point mutations in SRY region of Y chromosome results in female sex organs in XY individuals

Question 3

What is Androgen insensitivity syndrome?

Answer 3

Caused by lack of functioning androgen receptors in XY individual, development of female with no internal sex organs

Question 4

What is Turner’s syndrome?

Answer 4

Presence of only X chromosome results in lack of ovaries but otherwise normal female sex organs and genitalia.

Question 5

What is Persistent Müllerian duct syndrome?

Answer 5

Lack of anti-Mullerian hormone causes development of both male and female internal sex organs in an XY individual

Question 6

What is the Aromatisation hypothesis?

Answer 6

Suggestion that in some CNS cells, testosterone is converted into estrogen by aromatase before it acts on estrogen receptors to exert masculinising effects.

Question 7

What is the protection hypothesis?

Answer 7

Idea that brains of developing rodents are ‘protected’ from masculinising action of estrogen by alpha-feto protein.