sex differences

What determines the baby’s chromosomal sex

Presence/absence of Y chromosome

What is a gene SRY

Crucial gene on the Y chromosome - if it is not present Gonad turns into overy

What 2 hormones does the testes produce during development

Anti - mullerian (defeminising)

Androgen (testosterone falls into this)- masculating

What is anti mullerian hormone

What is the mullerian system

Precursor to female internal sex organs

What is the wolfian system

What hormone is required to develop the wolfian system

Androgens

What does DHT stand for

Dihydrotestostrone

What does DHT do

Type of testosterone made by the testes and turns external anatomy to a male specific anatomy

What is persistent Müllerian duct syndrome

Male with external genitalia, with testes, male and female internal genitalia.

What is androgen insensitivity syndrome

Person with female external genitalia

What is Organisational act of a hormones

Hormone does something to make a change and that change is permanent after the hormone is a removed

When does organisational act of hormones occur

Often during the sensitive period

What is the activational act of a hormone

Hormone is causes an effect on brain or body but it dependant on the presence or absence of the hormone

What happens during puberty

Organisational and activational hormones

Secondary sexual characters develop

Public and axillary hair

What hormones impact Public and axillary hair

Androgen

What Are examples of organisational hormal effects

Wider pelvis in women

Wide shoulders in men

Lowering of voice in men

What are examples of activational hormone effect

Increased facial hair in men

Breast development in women

Increased muscle mass

What occurs during puberty

In the hypothalamus there group of GnRH neurons that do not release sex hormones during childhood as GABA/NPY inhibits KNDy neuron which is needed by GnRH neurons to act as a modulator. But this change during puberty when KNDy is not longer inhibited

How does GnRH hormone cause the onset of puberty

They are activated by KNDy when it’s no longer inhibited. GnRH os released into the bloodstream and travels to pituitary gland and the realse of gonadotropins (from pituitary portal system) which then travels to testes and ovaries to stimulate the production of hormones

What are the 2 types of Gonadotropins

FSH (follicle stimulating hormone)

LH (luteinising hormone)

What hormones does the ovaries release

Oestrogen and progesterone

What is FSH in males

Follicle stimulating hormone sperm productions

What is FSH in females

Follicles ripen

What does LH do in males

Testosterone production

What does LH do in women

Luteinising hormone induce ovulation and formation of corpus luteum

What is corpus luteum

Yellow body makes oestrogen and progestrogen (creates the uterus lining)

What happens to the HPG (hypothalamus pituitary gonad) when taking anabolic steroids

Hypothalumus produces less GnRH and lowers testorone in testes and testes shrink (not being stimulated by FSH and LH

What are anabolic steroids

Mimic testosterone

What occurs during the menstrual cycle

What is 5a - reductase deficiency

An enzyme that turns turns testosterone into DHT (dihysdrotesterone). This is needed to produce male external genitalia, so a deficiency doesn’t allow this to occur.

What is congenital adrenal hyperplasia

What happens in puberty for those who have 5a reductase deficiency

There are high levels of testosterone which mimic DHT and develop male genitalia

Why are there sex differences in the brain

Hormones

Genetic

Environment (peers and culture)

Why do children have toy preferences

What are the structural differences between mal and females

Males have bigger brains

Females have a thicker cortex - more grey matter

Males have larger white matter and subcortical structures

What is gynophile

Males attracted to females

What is androphile

Female attracted to male

What are the 4 sex differences in brain and behaviour

Experiential/cultural effects

Activational hormonal effect

Organisational hormonal effect

Genetic effects

What is the activational hormonal impact on behvaiour

High testostrone increase interest in sex

What Organizational hormal impact sex differences

How specific hormones have caused the onset of sex different aspects of the body (i.e genitalia)

When is testosterone high in boys during development

8-24 weeks of pregnancy ( early= external genitalia, late= brain differentiation)

First 3 months after pregnancy- further brain differentiation

How have better verbal abilities

Androphile men

Who has worse vision spatial performance

Androphile

Who has quicker mental rotation

Gynophile women

What are 2d/4d ratios

Ratios of fingers from index finger to ringer finger

Who has a larger ratio of 2d/4d

Females at 0.97

What causes the 2d/4d ratio

Testosterone dependant

What are oto acoustic emisssion

Stimulated clike makes the ears sound back

In who has higher oto emission

Female

What are CAH females more likely to identify their sexual orientation as

Gynophile

What does most evidence point to as a factor for developing gynophile adults

Prenatal testosterone

How do we test for the gentic effect on sexual orientation

Twin studies

Genetic mapping

Evolutionary angle

Fraternal birth order effect

How does twin studies show sexual orientation

Higher concordance in Mz than Dz at about 30 to 100%, possibly higher in women than men

How does genetic mapping show sexual orientation

Family tree can show androphile men have androphilic maternal uncles by showing a an X chromosome inheritance pattern

What is the evolutionary concern on sexual orientation

Natural selection - only heterosexuals can have offspring

What is the heterozygote advantage

How does the fraternal birth order effect determine sexual orientation

A man is more likely to be homosexual the more genetic older brothers he has

Is gender identity a single phenotype

NO - there are multiple descriptions of gender identity

What did research find about gender predispositions on gender dysphoria

Found alleles that played a part