CNS and Neurotransmitters

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    The role of the Central

    Nervous System and

    Neurotransmitters inhuman behaviour.

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    The Nervous System has 2 main partsthe Central

    Nervous System (CNS) and the Peripheral NervousSystem.

    The CNS consists of the brain

    and the spinal cord.

    The brain is within the skull and the spinal cord is within

    the vertebrae.

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    Parts of the brain and spinal cord

    The Brain

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    Continued: Find out the function of the following brain

    parts: Hippocampus

    Ventricles

    Amygdala

    Hypothalamus

    Hemispheres

    Striatum

    Thalamus

    Cerebellum

    Cortex

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    Neurotransmitters

    Neurotransmitters are chemical messengers that act between the neurones

    in the brain. This allows the brain to process thoughts and memories.

    The nervous system contains neurones and gliaglial cells carry out

    repairs and remove waste products from the brain.

    Neurones receive and transmit messages, passing them from cell to cell.

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    Place the following in the correct order

    The axon terminal of one neurone reaches to thedendrites of another.

    The synaptic gap or cleft sits between two neurones.

    At one end, a neurone has dendrites which surround thenucleus.

    On one side, at the dendrites, there are receptors of acertain shape, prepared to receive the neurotransmitterfrom another neurone.

    From the nucleus, there is a long extension called an

    axon, which reaches to an axon terminal. If the neurotransmitter fits the receptor the message is

    passed on; if it does not, the message is blocked.

    Between the terminal and the dendrites, there is a gapcalled a synapse.

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    How Synapses work

    You will need notes on how messages are

    passed via neurotransmitters

    http://www.youtube.com/watch?v=HXx9qlJ

    etSU

    http://www.youtube.com/watch?v=HXx9qlJetSU&feature=relatedhttp://www.youtube.com/watch?v=HXx9qlJetSU&feature=relatedhttp://www.youtube.com/watch?v=HXx9qlJetSU&feature=relatedhttp://www.youtube.com/watch?v=HXx9qlJetSU&feature=related
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    Neurotransmitters continued:

    RECEPTORS can be thought of as locksif acertain chemical (neurotransmitter) fits like a

    key, then the message is passed on: if it does

    not then the message is blocked.

    Manufactured drugs work in this waythey

    mimic neurotransmitters, more or less fit certain

    receptors, are received like neurotransmitters

    and the message from them works. Somedrugs block the messagethey fit the receptor,

    so the natural neurotransmitter cannot pass the

    message on because the receptor is not

    available.

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    The Role of Genes in Human

    Behaviour

    NOI said GENES

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    A GENE contains a set of instructions and is a

    carrier of information.

    Each individual human has a genotypethis is

    the genetic composition

    Each person has a phenotype which is what the

    individual becomes when their genes interactwith each other and the environment.

    A gene consists of a long

    strand of DNA A chromosome is a double

    chain of DNA

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    Some genes always lead to certaincharacteristics; these are known as dominant

    genesto produce a characteristic, dominantgenes need to be on only one pair ofchromosomes.

    Some genes need more than one copy to

    produce a characteristic; these are known asrecessive genesif a recessive gene is presenton only one of the pair of chromosomes, thecharacteristic will not appear.

    However, they can be passed on and mayappear in a future generation.

    Characteristics can be aspects of appearance,personality or behaviour.

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    Examples of the effects of genes on

    humans

    Some diseases and characteristics are sex linkedthey

    are controlled by the sex genes. E.g. most colour blind

    people are men

    If one parent contributes two copies of chromosome 21,

    then the child has three copies and the consequence isDowns Syndrome.

    Human chromosome 4 has a marker known as G8if a

    parent and child both have Huntingdons Disease, then

    in 98% of cases they both have the same form of G8markersuggesting that the gene for Huntingdons

    travels with the G8 marker

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    Huntingdons Disease

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    Environmental triggers on genes

    Sometimes genes do not influence

    physical characteristics unless the right

    environmental conditions occur. Find out about PKU (phenylketonuria)

    what is it? How can the damage from this

    condition be reduced?

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    PKU

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    The Nature Nurture Debate

    What do psychologists mean when theytalk about the naturenurture debate?

    Write down some characteristics that you

    have which you believe are caused by

    nature.

    Write down some characteristics that you

    have which you believe are caused by

    nurture.

    Which characteristics may be caused due

    to an interaction between nature and

    nurture?

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    Biological explanations for gender

    developmentwe will.

    Consider how biological psychologists

    might explain sex & gender

    Examine chromosomal influences on

    sex/gender development

    Examine hormonal influences on

    sex/gender development

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    Sex chromosomes

    Genetic blueprint for a person is organised

    into 23 pairs of chromosomes

    22 pairs are both X shaped. the 23rddepends on whether the person is female

    or male

    XXfemale XY - male

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    Sex chromosomes

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    Chromosomes & hormones

    Everything develops as a female unless

    instructed otherwise

    The Y chromosome contains instructionsfor the body to produce androgens (male

    sex hormones)

    These cause the embryo to develop alongthe male path

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    Sexual development

    At about 6 weeks gestation the GONADS

    or sex organs begin to develop but there is

    no difference between developing sexorgans of males and females at this stage.

    Later, the gonads begin develop differently

    What does the gene in the Y chromosomecalled SRY do?

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    HORMONES

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    Which protein hormone is released at

    about 6 weeks into foetal development? What does this hormone do?

    What are the undeveloped sex organs of

    both men and women called? What is the name of the first hormone to

    be released by the testes and what does it

    do?

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    Abnormal sex differentiation and

    development Problems with sex differentiation can occur at any time

    during development.

    Problems can arise at fertilisatione.g. boys with XXY

    chromosomes develop Klinefeltere syndrome and girlswith XO chromosomes have Turners syndrome.

    Incorrect Mullerian or Wolffian duct development canalso cause problemsthe foetus might not respond toandrogens, in which case the foetus will have neithermale nor female internal duct structures and lack of theMullerian (female) inhibiting substance but withandrogen secretion can lead to a foetus having bothmale and female duct structures.

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    Klinefelters syndrome

    Physical differences (stature, limbs)

    Underdeveloped genitalia

    Gynaecomastia in some cases

    Poor language abilities, learning difficulties

    Shy and passive temperament

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    Klinefelters syndrome

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    Klinefelters syndrome

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    Turners syndrome

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    Turners syndrome

    Physical differences (neck, stature)

    Underdeveloped ovaries, lack of

    menstruation at puberty

    Poor spatial and mathematical abilities

    Poor social adjustment

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    Turners syndrome

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    Hormones and Gender Development

    Like neurotransmitters, hormones carrymessages

    However, the messages are passed much more

    slowly because hormones travel in the

    bloodstream

    They affect numerous

    processes such as growth,

    development, mood andmetabolism

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    They are produced by endocrine glands, whichare groups of cells and include the pituitary,

    thyroid and adrenal glands

    They are also produced by males in the testesand females in the ovaries

    The female hormones are oestrogen andprogesterone

    The male hormones are androgens such astestosterone

    Collectively these are called reproductive organs These dictate gender differences and cause the

    male and female brains to develop differently

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    Human Brain

    Corpus callosum: the bundle of fibres that connects the two

    hemispheres

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    The Male Brain

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    The Female Brain

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    Hormone differences can affect health and

    lifestyle throughout a persons life. For examplemore females develop pain

    syndromes like fibromyalgia and they alsotend to suffer more from mood disorders

    such as depression and anxiety. On theother hand, more men than women arelikely to develop alcoholism and to abusedrugs.

    Find out about ANDROGENITALSYNDROMECause? Symptoms?

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    Brain Lateralisation

    What is meant by the term brain lateralisation?

    What are the 2 parts of the brain known as?

    What connects the 2 parts of the brain?

    It is claimed that the left and right sides of thebrain are concerned with different thingswhatare these?

    What evidence is there for brain lateralisation?You will need evidence from studies heree.g.Pfeiffer

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    Men Vs Women

    Men(unilateral => stroke affects)

    Women(the corpus callosum is larger)

    Left Hemisphere Right Hemisphere Left Hemisphere Right Hemisphere

    More active in

    linguistic tasks

    Bilateral in linguistic tasks

    High activity in

    spatial tasks

    Bilateral in spatial tasks

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    Speech CreativityAnalysis Patterns

    Time Spatial

    ability

    Sequence Context

    Recognition awareness

    Words Face

    Letters recognition

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    Test your Brain Sex

    You can do this by logging on to the

    following link and completing the testit

    will take about twenty minutes. http://www.bbc.co.uk/science/humanbody/

    sex/index_cookie.shtml

    Please do this and print out your findingsbring to class after half term

    http://www.bbc.co.uk/science/humanbody/sex/index_cookie.shtmlhttp://www.bbc.co.uk/science/humanbody/sex/index_cookie.shtmlhttp://www.bbc.co.uk/science/humanbody/sex/index_cookie.shtmlhttp://www.bbc.co.uk/science/humanbody/sex/index_cookie.shtml
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    Evaluation of biological explanations for

    gender development

    The Case of David Reimer

    The results of biological explanations are based

    on tests that can be repeated e.g. injecting ratswith additional testosterone or using MRI

    scanning in humans to detect blood flow. The

    results are replicable and can be shown to be

    reliable

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    Different research methods are used and tend tocome up with similar results e.g. sex differences

    in brain lateralisation. There is a problem with generalisability because

    many findings come from animal studies; thereare important differences in the human brain, so

    such findings may not be relevant to humansand may not be credible.

    Biological aspects are difficult to study withoutreference to the environment; for example male

    and female children are reinforced for differentbehaviour; this may mean that they use differentstrategies to do tasks rather than that they havedifferent brain structures (SLT)

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    Pseudo hermaphroditese.g. Daphne Went

    this evidence refutes the genetic explanation of

    gender development. How?

    Androgenital syndrome and Androgen sensitivity

    syndrome support the argument that pre natal

    exposure to certain hormones determinesgender developmenthormone exposure can

    override genetic sex.

    There is an argument that gender is a result of

    interaction between biology and environment.

    From the moment a child is conceived, it is

    subject to influence from the environment.

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    http://myhome.iolfree.ie/~lightbulb/Line.html