5 - hormones and sex

Question 1

what do hormones do?

Answer 1

underpin signalling within brain-body systems

act to maintain a desired ‘set-point’ or ‘desire state’ in terms of behaviour or physiology

Question 2

how do hormones travel throughout the body?

Answer 2

vascular system

Question 3

why is the hypothalamus seen as a master controller?

Answer 3

part of brain so receives contextual information and sensory input

it compares this to the biological set points

Question 4

structure of hypothalamus and pituitary gland

Answer 4

pituitary gland hangs off of the hypothalamus on the infubidilum

Question 5

what is the difference between the anterior and posterior pituitary hormones?

Answer 5

anterior pituitary has a 2 step release mechanism

anterior - neurosecretery cell releases hormones into blood vessels that go into pituitary gland that causes more hormone release

postirior - goes straight from hypothalamus and causes hormone release

Question 6

what is chromosomal sex?

Answer 6

most humans have 22 pairs of autosomes (matching) and one pair of allosomes (not matching)

differences in allosome are associated with biological aspects of phenotypic sex

it is fixed

Question 7

what is phenotypic sex?

Answer 7

internal and external genitalia, secondary sex characteristics

XX - ovaries, vagina etc
XY - testicles, penis etc

it is modifiable

Question 8

what is gender?

Answer 8

individuals subjective perception of their sex

emerges from self-appraisal in the context of social or cultural norms

it is constructed

Question 9

what is turner syndrome?

Answer 9

missing X chromosome (XO) affects females

tend to be shorter and have impaired ovary function

have reduced levels of oestrogen and progesterone so under development of secondary sex characteristics

infertility or reduced fertility

Question 10

how to treat turner syndrome?

Answer 10

give oestrogen and progesterone

Question 11

what is Klinefelter’s syndrome?

Answer 11

extra X chromosome (XXY), affects males

tend to be taller and impaired testicular function

reduced levels of testosterone leads to under development of secondary sex characteristics

infertility or reduced fertility

Question 12

what is treatment for Klinefelter’s syndrome?

Answer 12

testosterone

Question 13

what is XYY syndrome?

Answer 13

extra Y chromosome, affects males

tend to be taller, risk of learning or speech development problems, but symptoms mild so many never diagnosed

normal fertility

Question 14

what is treatment for XYY syndrome?

Answer 14

supported learning

Question 15

what is the SRY gene?

Answer 15

a sex-determining region of the Y chromosome

important for ‘diversion’ toward male biological development in utero (at around 6-8 weeks)

Question 16

what happens if we chemically block SRY action?

Answer 16

results in genetically male person with ovaries

Question 17

what happens if we inject SRY protein?

Answer 17

results in genetically female person with testes

Question 18

why do men have nipples?

Answer 18

they are made before the SRY gene activates

Question 19

what governs development of secondary sex characteristics?

Answer 19

gonads (ovaries and testes)
considered a key part of phenotypic sex

Question 20

how does puberty effect hormone release?

Answer 20

the release of sex hormones inhibit hypothalamus and pituitary gland

reduction in sensitivity of Hyp/AP starts puberty

pulsatility rate increases towards puberty, leading to increased LH and FSH signalling, elevated concentration of sex hormones, triggering puberty

Question 21

how do hormones regulate menstrual cycle after puberty?

Answer 21

changes in pulsatility of GnRH release

Question 22

what is the historical view of brains within genders?

Answer 22

sex hormones lead to differentiation of male and female brain, similarly to how they determine primary and secondary sex characteristics

Question 23

is there a neurobiological basis for gender?

Answer 23

WHO includes ‘behaviour associated with being a man or women as well as relationships with each other’ in their definition

neuroscientists and psychologists see behaviour as emerging fairly directly from the brain

Question 24

what is the role of neuroscience regarding gender?

Answer 24

explore sex-related differences in brain structure and function

Question 25

what are sex differences in the brain?

Answer 25

male brains weigh about 10% more than female brains

most of this difference is explained by differences in body mass

Question 26

what are problems with research investigating sex differences in the brain

Answer 26

motivations: researchers motivated to find differences

bad design: even if comparison is found, it may not be significant

questionable comparisons: difference species have sexual dimoriphism (differences in phenotypes) to different degrees, humans don’t have high degree

publication bias: finding a difference is more likely to get published

Question 27

why care if there are sex differences in the brain?

Answer 27

many conditions have different levels of incidence depending on sex

is this down to brain differences or other factors (social, behavioural, environmental, educational)

Question 28

what did the human brain mosaic demonstrate?

Answer 28

variation across individuals within a gender category is greater than that between categories