hormonii 2 Flashcards
what is activating effect
reversible changes that in the properties of cells
typically induced by hormones that are present onto the cell receptor for a short amount of time
what is organisational effect
a permanent or semi permanent change in the strucutre of the nervous system
change occurs during sensitive periods
the changes happen because steroid hormone - which is able to cross the cell membrance bc its fat solouable and it binds onto a recpetor that is a steroid receptor and enters the cell nuclues where its able to modefy or induce changes in gene activity
what is sexual development
development of sexual organs
and secondaty sexual feautres - breaking of the male voice
sexual identity
changes in the nervous system
how do changes occur
stage 1 - undifferentiated stage
2- sexual differentiation
undifferentiated stage
earlystage that covers the very first weeks of gestation
between fertilisation and week 7
during this point, there is a strucute called gonad which is identical in males and females
gonad will become either ovaries or testies
strucutre has power to develop in either one on the other depending on genetic profile
sxual differentiation stage
at about 7 weeks
gonat becomes ovaries or testies
how does that happen
- organisatinal effects in physical development
y chromsone is a sex determinant gene
makes gonat develop into testies
of y is not present then the gonat becomes an ovary
this is dependent on genetic profile
boys have y chromsone
at abotu 9 weeks of gestation, thre is another key transoframtion
testis produce steroid hormones called androgene - androgene include one hormone claled testosterone
testosteronq
induces or triggers the development of internal and external genitalia in males
also inhibts the development of similar structures in females such that females will develop female genitalia
testoster induces changes in the nervous system
how
testosterone reaches the brain
they hypothalamus
hypothalamus is divided into different parts called nuclei that have different functions
one of this nuclei is sexually dimorphic nuclues - located in an area that is preoptic area
sexually dimorphic nuclues tends to be larger in males
when test reaches the brain, it csn cross the membrance and its chemically transformed into another type of hormone that is estradiol
estradiol can reach the nucleus membrance and reach centre of the cell
this will trigger a no of reactions that achieve the masculinisation of the brain
in females
there is a natural death of sexually dimorphic nuclues which will prevent female brain from being masculinsed
genetic differentiation such that boys have a y chromosme
that will tranform gonat into testies
testies will secrete testosterone
test reaches the brain and triggers masculinisation of the brain
changes occur during sensitive period
a period of maximum sensitivity
specific point in time during which certain changes occur such that they will not result in the same outcome if they were to happen at a different point in time
gonadogenesis sensitive period in pre-natal development
typically starts about week 7 and end about week 9
impact of sexual hormones on physical differences
full development of sexual organs
sex hormones in adolescnce will be accompanied by the appearance of other sexual behaviour
imacpt of sexual hormoens on brain
when brain size is corrected by body size
gender differences in brain size
boys have a higher brain weight
left hempishere larger in females
right hemisphere larger in males
from recent studiess
gender differences in brain volume are specific for some areas of the brain
women show higher brain volumes in areas which are rich in eostrogen receptors - prefrtaonal regions
men show hgiher volume in medial and orbital frontal cortex and angular gyrus - higher density of androgen receptors
size of corpus callosum
the fibres connecting the 2 hemsiphers
women have a larger corpus callosum -its thicker
consequence - faciliataion for womn to tansfer info between the 2 hemsiphers in a m ore efficent way
brain wiring - connectivity between brain regions
in males the brain is well connected throughout
in females the connectivyt is focusing on frontal areas and they are more denseliy connected
brain rate od brain development
during adolescnce girls are more mature
there is evidence that supports this observatio
certain processes are triggered later in boys than girls
girls begin maturation processes earluer
one maturation process is decrese in brain volume
brain is eliminating synapses that are irrelavant - synaptoic pruning
this allows brain to improve communciation between different regions such as the frontal lobes
pruning happens later in boys
how gender differences have been interpreted
- male brain and female brain
- brains are intersex
- gender similarity is more common thatn gender disimilarity
male brain and female brain
the idea that our physical differences and gender dissimilairty is guiding sex linked traits which are persistent across time and cluture bc they are passed on bia inherited biological sex
we can have a female brain which is not so prototipically female
evidence for male and female brain
there are differences in brain strucutre which are teflected in different higher congitive abilities
men - spatial rotation
women - verbal fluency
task assessing higher cognitive functions in males and females
there are certain tasks in which males perform higher than femaes
task requires spatial relation
a contained has a certain level of liquid who are asked to match with a container that is tilted
men are faster and more efficient at indicating that this upright container matches the tilted one
men are more accurate at indicating which cubes correspond to the plan - task requring mental rotation
females appear to be faster at matching number to symbols
they are faster at filling up a set of words tha begin with a given letter - verbal fluency abilities
brains are intersex
although we have a distinction between male and female genitalia, this disctinition does not mirror a distinction at the brain level
this suggests that most brain consist of a mosaic features - some are more common in males and vice versa
each of us have prototypical female features and other prototypical male features combined
study
females did have on average more prototypicall female areas but they also had male protoypical areas
each participant had a predominantely either pink or blue amount but there was always a combination of the 2 such that certain parts of the brain corresponded to more female or male brain - and some parts were more simialr to the opposite gender
anatomical evidence
there are certain brain regions that are larger in males than femakes
part of the hypothalamus - the intermediate nuclues is on average 2x as large in males
however about a third of males the intermediate nuclues is the size of typical of females
cognitive evidence
tendency to identify certain psychological traits, attitudes or behaviours as gender oriented
there is also a no of situations in which somebody who is a man has female features like certain hobbies or personality traits that are on average associated to females
the gender similairty hypothesis
male and females are more simialr than different on most variables
cognitive evidence
46 meta analysis suggest that gender differences exist but are reality tiny and certinly not significant
there are certain areas that are typically associated with gender differenees which some studies suggest this difference is not relevant up to a certain age - boys and girls up to age 9 and 10 will perform equally well in science and maths ability tasks
the sterotype might have certain influcnes
the disceprency between what we see at a certain age and what we see later one is more likley due to social attitudes and social biases rather than actual performance
a study in which partiicpants were tested in a maths related test which was either easy or difficult
ppt perfomred similar in easy condition with a difference indifficult condition
when ppts were told that the task they were going to perform was going to reveal gender differences, a gender difference emerged in performance
female partiicpants performed worse and male ppts performed way better making the gap much bigger
tendency of males to show higher peformance in tasksmthat require spatial orientation using a map
tendency of women showing a better orientation when they use ladn marks
when the possibility of only using one of these, gender differnces are no longer present
some gender differences might relfect strategies which could be different but they are not the equivalent of abilities
