Lecture 2 Heredity, the Brain, and Prenatal Developmen Flashcards

1
Q

what is a genotype?

A

genetic material an individual inherits

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2
Q

what is a phenotype?

A

observable expression of genotype, including body characteristics and behaviour

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3
Q

what is an environment?

A

includes every aspect of the individual and his or her surroundings, other than genes

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4
Q

what is a chromosome?

A

threadlike structure found in the nucleus

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5
Q

what is DNA?

A

double-stranded molecule that makes up the chromosomes

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6
Q

what are genes?

A
  • basic units of heredity
  • each chromosome has thousands of genes, small segments of DNA
  • a gene is expressed if it has been turned on to make its specific protien
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7
Q

what did every person start out as?

A

1 cell ( which we refer to as a ZYGOTE)

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8
Q

What is a zygote made up of?

A

It is basically a singular cell which is made up of sperm ( 23 chromosomes) and ova ( 23 chromosomes)

  • each parent contributes half to the makeup of the zygote
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9
Q

What are alleles?

A

when the same gene has many different forms

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10
Q

the effect of any gene or set of genes is …

A

probabilistic

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11
Q

what is phenotypical plasticity?

A

the degree to which environmental factors affect a given trait

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12
Q

what is canalization?

A

when certain characteristics are restricted in their outcome, even if the environment varies widley; to summarize, they’re a less likely to get influncs to variations in the environment ( like language for an example)

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13
Q

what is norm of reaction?

A

range of possible phenotypes for a given genotype

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14
Q

what is epigenetics?

A

complex process which environment shapes the expression of genes

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15
Q

what are the four ways in which genes and the environment react?

A
  1. environmental factors turn genes on/off
  2. environmental factors alter magnitude of genetic effects on development
  3. gene expression can affect how people respond to children “evocative”
  4. Genotype affects the type of environments the person seeks out - “active”
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16
Q

what are the basic units of the brain

A
  • neurons
  • synapses
  • glia
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17
Q

what are neurons

A

communication cells

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18
Q

what are synapses

A

connectie spaces between neurons

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19
Q

what are gila

A

suppoting cells that produce myelin

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20
Q

whats a myelin

A

a sheath that allows electrical impulses to transmit quickly and efficiently along the nerve cell

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21
Q

what are the four lobes of the cerebral cortex

A
  1. frontal lobe ( movements, attention impulses )
  2. parietal lobe ( touch, pain, and body position
  3. occipital lobe ( visual cortex)
  4. temporal lobe ( smell, taste, hearing, and language)
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22
Q

Explain the stages of brain development

A
  1. Neurulation ( formation of neural tube)
  2. Neurogenesis ( birth and migration of neutrons)
  3. Circuit formation (synaptogenesis and synaptic pruning )
  4. Myelination ( formation of fatty covering on axons)
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23
Q

explain Neurulation

A
  • happens 3 weeks after conception
  • neural tubes form from ectoderm
  • cells inside the tube the (CNS) central nervous system cell outside the tube from the (PNS) peripheral nervous system
24
Q

explain neurogensis

A
  • the proliferation of neurons through cell division
    a ) this begins as soon as the neural tube starts to form and is complete by the 18th week
    b) 100 billion before birth
  • during this stage neuron migration mappesn where neurons move to appropriat place in the brain
25
Q

explain the third stage of brain developemt circuit formation

A
  • synaptogensis takes place whihc is most rapid in pre and postnatal periods. lots of overproduction of spynapses are producded than the amount that twill acc be used
  • the peak amt of synapses happens at diff times around diff brain regions ( like during adolesence the visual corext will lower and prefrontal corext will be in peak)
  • synapse pruning also happens at this stage. it is where experince determines whihc synapses will live or die ( kind of like use it or lose it) the time of pruning also varies across brain regions) like a two yearold will have more acticty than a six yearold
26
Q

explain myelination

A
  • the variability in timing across brain regions ( this is related to when you develop certain skills)
  • motor and visual circuits myelinated in infancy
  • frontal mylination contunies until adolsecnes or adulthood
27
Q

what can interfere with mylination

A

nutritional deficiencies

28
Q

the timing of brain develoment differs for ….

A

diff brain

29
Q

what is developmemntal plasticty?

A

how much brain development is open to modification by the environment

30
Q

what does the effect of an experince on the brain depend on?

A
  1. timing
  2. dose
  3. duration
31
Q

how does experince influence the developing brain?

A

experience expectence plasticty

32
Q

what is experience expectence plasticty

A

The brain adapts in response to existing sensory
information (species-typical experiences)
– Due to pruning of synapses that were overproduced
– Sensitive periods

33
Q

provide an example of experinece plasticy

A
  • Vision – babies born with cataracts
    – Language – Genie
34
Q

what are Critical periods?

A

A very narrow period during which a particular
experience must occur for development to proceed
normally

35
Q

give an example of a critical period

A

Imprinting in chicks

36
Q

whats a Sensitive period?

A

A developmental stage during which the brain is most susceptible to experiences, but changes are still possible
outside of this window

37
Q

what is Experience-dependent plasticity?

A

– Changes in the brain due to an individual’s unique
personal experiences
– Due to formation of new synapses throughout the
lifespan

38
Q

what is an example of experience dependent plasticty

A

– Adult violin players
– London cab drivers

39
Q

what is Prenatal Development

A

Conception to birth
* Begins when sperm penetrates egg
and forms a zygote
* Zygote has full complement of genetic
material, half from each parent
* Takes about 266 days for the one-celled
zygote to become a fetus of 200 billion cells

40
Q

what are the 3 stages of Prenatal Development

A

1.Germinal period (days 0-14)

  1. Embryonic period (weeks 3 – 8)
  2. Fetal period (week 9 – birth)
41
Q

what is the embryonic period

A

(weeks 3 – 8)

– Formation of major organs
– Formation of major organs

41
Q

whats germinal period

A

is days 0-14

– From conception to implantation in uterine wall (zygote)

42
Q

whats the fetal period

A

(week 9 – birth)

– Organ systems begin to function
– Significant growth

43
Q

what are some milestones during gerninal period

A
  • Zygote travels towards
    uterus
  • Cleavage:
    – The division of the zygote
    into many cells
    – Begins ~24 hours after
    conception
    – Occurs while the zygote
    travels down the fallopian
    tube towards uterus
  • By the 4th day after conception, the
    zygote arranges itself into a hollow
    sphere of cells (the blastocyst) with a
    bulge of cells, the inner cell mass, on
    one side.

*Blastocyst implants in uterine wall:
–Inner layer (embryonic disc) becomes embryo
–Outer layer (trophoblast) becomes:
*Amniotic sac
*Placenta
*Umbilical cord

44
Q

what are some milestones during Embryonic Period

A
  • Cephalocaudal
    development
  • Proximo-distal
    development

– 3
rd week
* Neural tube (from ectoderm) becomes the brain and
spinal cord; major areas of the brain begin to divide

– 4
th week
* Heart begins beating; limbs, eyes, ears, and digestive
system begin to form

– 5
th week
* Lungs begin to form

– 6
th week
* Head becomes dominant; brain is differentiated
– 7
th week
* Nerve cells form in the brain; muscles differentiate;
sexual differentiation

– 8
th week
* Ears are fully formed; fetus is capable of moving

45
Q

What does folic acid
have to do with prenatal
development?

A

baby needs folate to make healthy new cells, and to make DNA and RNA (genetic material). These are cell-building blocks. Folate also is essential to form normal red blood cells and certain amino acids

46
Q

what are some milestones during the Fetal Period: Last 7 Months

A
  • A period of rapid growth and refinement of
    organ systems
    – From 11⁄2 to 20 inches
    – From 0.02 to 7.1 pounds
  • Fetus becomes more responsive
  • Behaviour becomes increasingly regular and
    integrated
  • Fetuses become viable between 24-26 weeks
47
Q

when does a fetus begin learning

A
  • Responding to sounds in
    intrauterine environment
    ~6-7 months
48
Q

whats Habituation?

A

the fetus
decreases responses to
repeated or continued
stimulation, then increases
response to new sound

49
Q

do Newborn infants recognize
rhymes and stories
presented before birth?

A

yes, the will recognixe
- Cat in the Hat
– Mother’s voice
– Native language

50
Q

what do new brons prefer

A

Newborns also prefer
smells and tastes that are
familiar because of
prenatal exposure

51
Q

what are Teratogens

A

Any disease, drug, or other environmental agent
that can harm a developing embryo or fetus

52
Q

What are some possible teratogens?

A

– Maternal diseases
– Drugs
– Environmental hazards

53
Q

is it true that The same defect can be caused by different
teratogens

A

yes it is true

54
Q

what can result from a single
teratogen

A

A variety of effects

55
Q

what do the effects of tratogens depend on?

A

– Timing of exposure
– Amount and length of exposure (dose-response
relation)
– Genetic susceptibility of the fetus

56
Q

what are some other hazards and explain

A
  • Nutrition
    – Severe malnutrition in the mother ⇨ babies born low
    birthweight, later cognitive deficits
  • Stress
    – Prolonged and severe emotional stress is associated with
    stunted growth, prematurity, low birthweight, and
    irritable infants
  • Age
    – Prime time for childbearing: 16-35 years