Sex differences

Question 1

Sex determination in mammals

Answer 1

Female has 2 x chromosomes
Male has 1 x 1 Y chromosome

Question 2

what type of cells are gametes

Answer 2

haploid

Question 3

where is the SRY gene located

Answer 3

the Y chromosome

Question 4

what does the gene SRY do

Answer 4

turns the fetal gonad into testes

Question 5

what happens in the absence of the SRY gene

Answer 5

gonad becomes an ovary

Question 6

what two hormones are produced by early testis

Answer 6

Anti-mullerian hormone (defeminising)
Androgens (masculinising)

Question 7

what is the Mullerian system

Answer 7

precursor of female internal sex organs

Question 8

what is the Wolfian system

Answer 8

precursor of male internal sex organs

Question 9

what hormone develops the scrotum and penis

Answer 9

Dihydrotestosterone

Question 10

where is Dihydrotestosterone made

Answer 10

the testes

Question 11

what are the results of having persistent mulllerian duct syndrome

Answer 11

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

Question 12

what would be the result of an individual with androgen sensitivity syndrome

Answer 12

female genitalia

Question 13

what is an organisational hormone

Answer 13

Effect remains after the hormone has been removed

Question 14

when does organisational action of hormones tend to take place

Answer 14

Often occurs during a sensitive period - permanent changes

Question 15

what is an activational hormone

Answer 15

Effect is reversible, depending on presence or absence of a hormone

Question 16

what types of hormones are active during puberty

Answer 16

both organisational and activational

Question 17

what is androgen sensitive in both males and females

Answer 17

Pubic and axillary hair

Question 18

give two examples of activational hormonal effects

Answer 18

Increased facial hair in men
Lowering of the voice in men

Question 19

explain the action of GnRH

Answer 19

-released into the bloodstream
-enters anterior portion of the pituitary gland
-detected by receptors to promote the release of gonadotropins

Question 20

what does GnRH stand for

Answer 20

Gonadotropin releasing hormone

Question 21

Two examples of gonadotropins

Answer 21

follicle stimulating hormone (FSH)
luteinising hormone (LH)

Question 22

role of FSH in males

Answer 22

sperm production

Question 23

role of FSH in females

Answer 23

caused follicles to ripen

Question 24

role of luteinising hormone in males

Answer 24

testosterone production

Question 25

role of luteinising hormone in females

Answer 25

induce ovulation formation of corpus luteum

Question 26

what gland releases GnRH

Answer 26

hypothalamus

Question 27

what gland releases gonadotropins

Answer 27

pituitary gland

Question 28

what gland releases testosterone

Answer 28

testes

Question 29

what releases oestrodiol and progesterone

Answer 29

ovaries

Question 30

what type of system is the HPG axis

Answer 30

a negative feedback system - keeps testosterone around the same levels

Question 31

what does the HPG axis stand for

Answer 31

hypothalamus-pituitary-gonadal axis

Question 32

what do steroids bind to

Answer 32

testosterone receptors

Question 33

what is the effect of taking anabolic steroids on the HPG axis

Answer 33

Pituitary makes less LH and FSH The testes make low amounts of testosterone The hypothalamus producers less GnRH Testes will shrink

Question 34

what does the HPG axis control in females

Answer 34

the menstrual cycle

Question 35

what causes androgen insensitivity syndrome

Answer 35

androgen receptors do not work

Question 36

what happens to gonads with androgen insensitivity syndrome

Answer 36

develop as testes, but testosterone cannot do normal job

Question 37

46 XY individuals with androgen insensitivity syndrome

Answer 37

develop as female but without internal female genitalia typically identify as women

Question 38

46XX individuals with androgen insensitivity syndrome

Answer 38

not infertile but lack of pubic hair

Question 39

what is 5a reductase

Answer 39

an enzyme that turns testosterone into DHT

Question 40

what is DHT crucial for

Answer 40

prenatal external genital development

Question 41

46 XY children with 5a reductase deficiency

Answer 41

born with female external genitalia, but male internal genitalia

Question 42

what happens at puberty for 5a reductase deficiency

Answer 42

high levels of testosterone can mimic DHT so genitalia can develop

Question 43

21 hydroxylase deficiency in females

Answer 43

high levels of prenatal testosterone ambiguous external genitalia

Question 44

evidence of toy preferences as related to

Answer 44

correlations between play style and prenatal testosterone

Question 45

Alexander and Hines toy preference investigation

Answer 45

vervet monkeys female monkeys played with dolls and male with cars suggestive of factors above human experience (no culture involved)

Question 46

gender differences in spatial tasks

Answer 46

Men tend to be faster in spatial mental rotation tasks CAH 46XX individuals perform better than non-CAH 46XX individuals

Question 47

structural differences in brains

Answer 47

male brains - 10% larger female brains - cortex is thicker and tendency for larger corpus collosum

Question 48

what does gynophile refer to

Answer 48

human males are attracted to human females exclusively

Question 49

what does androphile refer to

Answer 49

human females are attracted to human males exclusively

Question 50

sex differences in sexual orientation

Answer 50

90-95% of males gynophiles 85-90% of females are androphiles

Question 51

structural differences for sexual orientation

Answer 51

SCN larger in androphile individuals INAH smaller in androphile

Question 52

evidence of sexual orientation in other species

Answer 52

8% of male sheep are exclusively interested in other males Sexually dimorphic nucleus (SDN) of preoptic area is smaller in these males

Question 53

how are hormones related to sexual orientation

Answer 53

Hormone fluctuations and manipulations affect motivation, but have no effect on orientation

Question 54

how do verbal abilities vary differ

Answer 54

better in androphile men than gynophile men

Question 55

how does visuo-spatial performance differ

Answer 55

worse in androphile men than gynophile men

Question 56

how does mental rotation differ (women)

Answer 56

faster in gynophile women than in androphile women

Question 57

what have twin studies shown about sexual orientation

Answer 57

Higher concordance in MZ than DZ twins Estimates from 30-100%

Question 58

what has genetic mapping shown about sexual orientation and what does this suggest

Answer 58

Androphilic men often have androphilic maternal uncles Suggests an X chromosome inheritance pattern area on X chromosome found as related to sexual orientation

Question 59

what are possible mechanisms for no selection bias for heterosexuality

Answer 59

Heterozygote advantage Different effects in males vs females Kin selection

Question 60

what is the fraternal birth order effect

Answer 60

Number of older brothers trend - more likely to be homosexual

Question 61

what is the maternal immune hypothesis

Answer 61

Mother's immune response to protein neuroligin 4 Y-linked predicts probability of having a male-orientated son