1 prenatal development

what are the three stages of prenatal development

germinal, embryonic and foetal

when does the germinal period occur

weeks 1-2

what is the germinal period

fertilisation and formation of the zygote, implantation into uterine lining and development of nourishing and protective structures such as the amnion, chorion, yolk sac, placenta and umbilical cord

when does the embryonic period occur

weeks 3-8

what is the embryonic period

central nervous system, internal organs, muscles and skeleton begin to form, heart begins pumping blood, neurons develop rapidly, external features begin to form such as eyes, ears, nose and limbs

when does the foetal period occur

week 9 to the end of pregnancy

when is the first trimester

weeks 1-12

what happens in the first trimester

organs, muscles and nervous system begin to organise, lungs begin to expand and contract, sex of foetus detectable with ultrasound

when is the second trimester

weeks 13-26

what happens in the second trimester

fetus is active, mother can feel movement, neurons rapidly form synapses, sensitivity to light and sound emerges

when is the third trimester

weeks 27-40

what happens in the third trimester

age of viability: 22-26 weeks

substantial growth and weight gain, rapid gains in neural connectivity and organisation, expanding sensory and behavioural capacities, signs of developing temperament

describe the formation of the brain during prenatal development

during the first month the neural tube forms, during the 6th month most of the brains neurons are in place and synaptogenesis begins, associated with new behavioural capacities, during the last trimester the cerebral cortex enlarges

describe fatal movement progression during prenatal development

fetal movement from week 8 onwards, felt by mother at 18-20 weeks (variable), behaviour becomes progressively more organised with gestational age

describe prenatal learning

foetuses respond to sound during the third trimester, can discriminate between familiar and novel auditory stimuli from the 32nd week

is prenatal learning retained after birth

hell yeah (DeCasper & Spence, 1986)

how many chromosomes do humans have and what are they made up of

23 pairs of chromosomes, each made up of multiple genes

what is a gene and what is the point

a small section of dna that codes for a specific protein, they are how characteristics are inherited from our parents

how many chromosome pairs are sex related

22 pairs are matching autosomes and the 23rd pair are sex chromosomes (xx female xy male)

what are alleles

different possible forms of a gene

describe the difference between homozygous chromosomes and heterozygous chromosomes

homozygous - the same allele was inherited from both parents

heterozygous - different alleles were inherited from each parent

explain the idea of dominant vs recessive alleles in genetic inheritance

dominant alleles always express their characteristics

both recessive alleles must be present to express their characteristics (recessive alleles can be passed to children even if not expressed in the parent)

homozygous inheritance of certain recessive alleles can cause serious disabilities and diseases

explain what polygenic means in terms of genetic inheritance

many genes contribute to a single trait, resulting in a combined trait or one that is intermediate between the two, eg. hair colour, height, skin colour

explain multiple alleles in terms of genetic inheritance

more than two alleles for a gene, affecting a single trait, resulting in codominance or incomplete dominance

explain what is meant by a mutation in terms of genetic inheritance

sudden, permanent change in a dna segment, can occur spontaneously or be caused by hazardous environmental agents

what are teratogens

environmental agents causing damage during the prenatal period

what are examples of teratogens

smoking, alcohol, drugs, environmental toxins

what effects can smoking have when done during the prenatal period

low birth weight, prematurity, impaired heart rate and breathing rate, infant death, asthma in later childhood, ADHD

what effects can alcohol have when consumed in the prenatal period

physical abnormalities, learning difficulties, hyperactivity, anxiety, fetal alcohol syndrome

what effects can drugs have when taken during the prenatal period

poor blood flow to placenta, babies born with signs of addiction

what effects can environmental toxins have if exposed during the prenatal period

mercury - cerebral palsy and cognitive impairments

arsenic - low birth weight and cognitive impairments

what effects can maternal diseases have if contracted during the prenatal period

rubella, hiv, gestational diabetes, zika

which maternal factors can impact the baby

diet, age, emotional state, poverty

sensitive periods?

what is a gene-environment interaction

genetic characteristics mediate responsiveness to environment

define epigenetics

factors modulating the expression of a gene

outline Radtke et al. (2011) study and findings

recruited women who had and hadn't experiences domestic violence during pregnancy

they measured dna for cortisol receptors (associated with a number of physical and behavioural problems)

in mothers there was no difference associated with their experience of domestic violence however when the children were aged 10-19 there was a significant difference in those who’s mothers had experienced violence during preganancy

the stress from experiencing domestic violence affected gene expression in the developing, unborn child that last through to adolescence