Sexual Differentiation Flashcards
What chromosomes do females and males have?
Females - 2 X
Males - X and Y
What controls for sexual differentiation?
The genes on the chromosomes and hormones
When does sexual differentiation occur?
Pre-natally
Female and male brain prenatally
It is the same - biopotential
Has tissue which supports either formation
What does bipotential mean?
Both possibilities
What do males and females both carry?
A set of mullein ducts and wolffish ducts as well as primitive gonads (testes or ovaries)
What determines what gender they become?
There is an SRY (sex determining region) on the Y chromosome - causes the primitive gonads to develop into testes - producing testoerone
What does testosterone cause?
The development of the wolffish ducts to develop into seminal vesicles and vs deferent
Mullerian inhibiting hormones causes degeration of the M ducts
What is the default sex?
A female
What is the difference in the gonadal hormones?
Males - have mostly androgens and a few estrogens (it is the androgen which determines the masculinisation of the foetus)
Females - have mostly estrogens and a few androgens
What is the role of androgens in females?
Associated with sexual desire
What does organising effects of gonadal hormones mean?
Occurs a few weeks after conception when the sex glands develop into male testes or female ovaries depending on the presence or absence of testosterone
Long lasting effects, occur before birth and at puberty
When do the organising effects occur?
in rats - shortly before and after birth
in humans - before birth (3rd and 4th month) and at puberty
What does activating effects of sex hormones mean?
These induce sexual function and behaviour - induce secondary sex characteristics that appear at puberty by activating brain circuits previously developed as pat of the organising effects
Can occur at any time in life when a hormone temporarily activates a response - only when the hormone is present
When do activating effects occur?
Only when the hormone is present
