The role of chromosomes and hormones (gender)

Question 1

What is someone’s sex and what 3 physical things determine it?

Answer 1

SEX= Biological structures, occurs as biological maturation takes place

• Egg fertilised by sperm carrying X or Y chromosome
• Gonads (testes or ovaries)
• Hormonal differences

Question 1

In terms of the role of chromosomes on gender, how is a female foetus formed?

Answer 1

• There is an egg with an X chromosome, and it is fertilised by a sperm carrying an X chromosome
• The 2 gonads will become ovaries
• The male elements will disintegrate
• Exterior anatomy develops into female genitalia

Question 2

In terms of the role of chromosomes on gender, how is a male foetus formed?

Answer 2

• There is an egg with an X chromosome, and it is fertilised by a sperm carrying a Y chromosome
• Gonads develop into testes
• A hormone is pumped out that absorbs all the female parts and then produces testosterone
• The result is a male with external male genitalia

Question 3

What happens to males and females during puberty?

Answer 3

• Male or female gonads release hormones from the pituitary gland or the hypothalamus
• This is testosterone for males, oestrogen+progesterone for females
• This stimulates the production of secondary sexual characteristics such as development of breasts and pubic hair

Question 4

What is the role of TESTOSTERONE in determining gender?

Answer 4

• Steroid hormone

-Stimulates growth of secondary sexual characteristics

(females can produce T, just less of it)

• Causes the development of male sex organs and also acts on the hypothalamus
• It’s associated with the masculinisation of the brain
• Also associated with male typical behaviour, eg aggression and competitiveness

Question 5

Role of testosterone- study by Money and Ehrhardt:

A sample of girls whose mothers took testosterone drugs during pregnancy exhibited ____-type behaviours.

They also showed a lack of ______-type behaviours

What does this suggest?

Answer 5

• MALE

-FEMALE

This suggests that testosterone has an effect upon gender behaviour.

Question 6

Role of testosterone- study by Deady

Answer 6

• Measured testosterone levels
• Gave BSRI to women aged 25-30
• asked questions about maternal personality (importance of having children and having a career)
• HIGH TESTOSTERONE LEVELS NEGATIVELY CORRELATED WITH LOW LEVELS OF MATERNAL PERSONALITY

——> suggests maternal drive is affected by testosterone

Question 7

What’s the role of OESTROGEN in determining gender?

Answer 7

• female hormone responsible for onset of menstruation and foetal development when pregnant

-Males can produce small amount

-there are behavioural effects= cause pre-menstrual tension, associated with emotionality, irritability, irrational behaviour and even criminality

-Diminishing oestrogen levels= the menopause

-Oestrogen also plays a part in ‘feminising’ the brain

• Also associated with female-type behaviours such as sensitivity and co-operation

Question 8

Research support for the role of oestrogen is…

Answer 8

ALBRECHT + PEPE

• Found that increasing oestrogen levels in pregnant baboons led to heightened cortisol production

-This assisted the development of organs and tissues in foetuses

–> suggests oestrogen plays a key role in promoting pregnancy

Question 9

What is the role of OXYTOCIN in determining gender?

Answer 9

• Acts as a neurotransmitter
• Produced in the brains of both males and females to control key aspects of the REPRODUCTIVE system
• Acts more in females:
  –>helps facilitate child birth by stimulating contractions
  –>helps in breast feeding
• Affects female social behaviour such as mate selection, ‘nesting’ behaviour, monogamy and nurturing acceptance and protection of offspring.

Question 10

How does Van Leengoed’s study support the role of oxytocin?

Answer 10

• Inhibited oxytocin production female rats shortly after birth
• Mothers showed a delay in maternal behaviour

-When the effects of the antagonist (that inhibited oxytocin) wore off, normal maternal behaviour was seen

——> supports idea that oxytocin is involved in the promotion of maternal behaviour

Question 11

How does Elbourne’s study support the role of oxytocin?

Answer 11

• Assessed the administration of oxytocin in 3000 patients in the 3rd stage of labour
• Found evidence of reduced blood loss–> supports idea of oxytocin in achieving successful child birth