Prenatal Development Flashcards
What are 2 key things psychologists used to believe about prenates?
–Limited cognitive abilities
–Fragmented and confused experience
What are the 3 key current beliefs about prenatal development?
- Experience rich, stimulating, coherent
- Learning
- Continuity
What 3 things are continuous between fetal and postnatal periods?
- Movement
- Rest-activity
- Language dev.
What were the 2 key historical methods for studying prenatal development?
- Indirect
- Autopsy
Give 2 examples of indirect historical methods for studying prenatal development
- Playing loud sound near abdomen
- Placing electrodes on abdomen to detect movement or heartbeat
What are the 4 key current methods used to study prenatal development?
- Fetal ultrasound cardiotocograph (CTG)
- Fetal ultrasound imaging (3D & 4D)
- fMRI
- MEG
What is the APGAR score?
Appearance
Pulse
Grimace
Activity
Respiration
When is the APGAR score taken?
1 minute and 5 minutes after birth
What are alleles? (1 word)
Genes
Genotype
Inherited genetics
Phenotype
Observable & measurable characteristics and traits
What are the two types of genetic inheritance? Give two examples of each.
- Simple dominant (e.g. tongue rolling, Huntingtons)
- Polygenetic (e.g. height, temperament)
Epigenetics
Study of how environment modifies, adds to, or inhibits the action of genes.
What are the 3 stages of prenatal development?
- Germinal
- Embryonic
- Fetal
When is the germinal phase?
0-2 weeks
When is the embryonic stage?
3-8 weeks
When is the fetal stage?
9 weeks–birth
When does implantation take place?
Day 6-10
What is implantation? (2)
–Zygote implanted in uteric wall
–End of germinal phase
How long is the prenate outside of the womb?
3 days!
During which phase does organ development take place?
Embryonic
What are the 4 main processes involved in organ development?
- Division
- Migration
- Differentiation
- Death
Zygote
The cell formed from the genetic information from both parents.
How many chromosomes does a zygote contain?
–46 total
–23 pairs
What are the two types of chromosome and how many are there of each?
Autosomes (22 pairs)
Sex chromosomes (1 pair)
When does the zygote form?
Day 1!
When does cleavage happen? (lol)
Day 2-3
What is cleavage? (2)
–Zygote divides
–Each division turns into 2 cells called blastomeres
What is mitosis?
–One of two types of cell division during cleavage
–Cell duplicates its chromosomes and divides into 2 genetically IDENTICAL “daughter” cells
What is meiosis? (3)
–One of two types of cell division during cleavage
–Only happens to germ cells (sex chromosomes)
–Cell divides into 4 cells, called gametes
How are gametes formed? (2)
–Formed through meiosis
–Contains HALF the chromosomes in the original cell
On what day is the prenate an early blastocyst?
Day 4
What happens on day 4?
–Cell differentiation
–Inner layer -> embryo
–Outer layer -> placenta
When does implantation happen?
Day 6-10
What is implantation?
–Blastocyst attaches to uterine wall
What proportion of zygotes fail to survive implantation?
3 out of 4
When is the embryonic period?
3-8 weeks
What three layers form during the embryonic period?
–Outer
–Middle
–Inner
What’s in the outer layer formed during the embryonic period?
Nervous system, skin, hair
What 2 key precursors to the nervous system at 4 weeks?
–Primitive head
–Neural plate that –> CNS & spinal cord
During what period does sexual differentiation occur?
Embryonic
What 3 key milestones happen at 11 weeks?
–Brain growth
–All organs present
–Spine and ribs
What 3 key milestones happen at 16 weeks?
–Lower body growth
–Movement up (breath, reflex)
–External genitalia
When do components of facial expressions present?
20 weeks
What 5 key things happen by 28 weeks?
- REM
- Neural activity like newborn
- Rest-activity
- Circadian
- Learning
What 3 key learning activities can take place at 28 weeks?
- Mother’s voice
- Music & language
- Emotional content
When does the foetus develop touch and what shows that they do? (3)
~8 weeks
–Plays with face
–Plays with umbilical cord
–Opens mouth
When does the foetus develop taste and smell and what shows that they do? (2)
~13 weeks
–Bitter, sweet, sour
–Big changes in parent’s diet during this period affects sucking and preferences for breastmilk
When does the foetus develop vestibular senses and what shows that they do? (1)
~25 weeks
Righting reflex
When does the foetus develop hearing and what 3 elements of sound can they recognize?
~25 weeks
- Speech
- Rhythm
- Pitch
When does the foetus develop vision and what shows that they do? (3)
~28-30 weeks
–Eyes close for sleep
–Eyes open & move when awake
–Can react to light from ~30 weeks
When does habituation begin?
30
Give an example of fetal habituation to visual stimulus. (2)
–Flash lights in specific order + measure cortical response using MEG
–> Shows similar response to previously learned patterns
Give an example of fetal habituation to auditory stimulus. (2)
–Mother reads poem
–When newborns played this poem if they suck in a specific pattern, quickly learn to do so
Give an example of fetal habituation to taste. (1)
If you drink carrot juice while pregnant, ur baby will like carrot juice.
Which organ develops THROUGHOUT the prenatal period (from ~3 weeks)?
Brain!
Neurogenesis
Brain development
When does the brain stop developing?
Early adulthood
At what age has neonatal preference for faces been recorded?
A few hours after birth
What are the 4 stages of brain development?
- Neurogenesis
- Neural migration
- Differentiation
- Synaptic pruning (death)
When does neurogenesis begin?
~3 weeks
–When ectoderm begins to form neural plate
What is neurogenesis?
The birth of neurons
What is neural migration?
Migration of neurons to their correct location
What is differentiation? (3)
–Neurons become different types
–Synapses form
–Myelination
What is synaptic pruning?
Pruning of connections between cells
How many neurons do we have?
About 100 billion
How many neurons is each neuron connected to?
~7000
How are new synaptic connections formed?
Learning
What is myelination?
Fatty insular forms around axon, make it go fast
What is the process of synaptic pruning? (5)
–Brain initially “overenthusiastic” in forming connections
–Synapse elimination to “fine-time” neural connections
–Leads to “functional networks”
–Strongly influenced by environment..!
–Pruned connections can be replaced
Do baby brains have more grey or white matter?
Grey
What is grey matter? (2)
–Cell bodies
–Dendrites
What is white matter? (1)
Axons
What is the brain like at birth? (3)
- 1/4 size of adult
- Generating lots of new synapses
- Pays attention to faces, familiar sounds
Chromosomes
Packages of DNA inside each cell’s nucleus
Genome
An organism’s complete set of DNA
How many DNA base pairs are there in each cell?
~3 billion
How many genes are there in a human genome?
Between 20,000-25,000
What 3 things do genes regulate?
- Formation and functioning of new cells
- Differentiation
- Timing and pace of development
What are chromosomal abnormalities? (3)
- Changes in number of chromosomes
- ‘Error’ in cell division or chromosome structure
- Random
What are genetic abnormalities? (3)
- Mutation of one or multiple genes
- May be environmentally influenced
- Usually inherited
What is the human genome project?
Sequencing the human genome–3 billion DNA base pairs
What are the 4 main potential benefits of the human genome project?
- Improve diagnosis
- Detect dispositions to disease
- Assess damage from radiation exposure
- Establish family relationships
What is Mitochondrial Replacement Therapy?
Allows folks with MRT to have their nucleus implanted in egg that has healthy mitochondria
Describe gene x environment interaction
Genes and environment interact to determine how genotype is translated into phenotype
Give 3 examples of the impact of prenatal environment on development.
–Nutrition
–Stress
–Perceptual/cognitive
Give an example of DNA being changed by your childhood environment
McDade et al 2017–babies who get more cuddles have their genetics changed -> lower morbidity
Teratogen
Environmental agents that can harm fetus
What are the three Ds of teratogens?
- Diet
- Disease
- Drugs
What 3 things can teratogens cause?
- Prenatal death
- Structural abnormalities
- Physiological changes
What 2 factors are teratogens sensitive to?
- Timing
- Dose
How did Zika virus affect newborns? (4)
–Small head
–Developmental delays
–Intellectual disability
–Behavioural and neurological differences
What’s PKU? (1+5)
Phenylketonuria
–Hyperactivity
–Brain damage
–Behavioural difficulties
–Tremors
–Epilepsy
What can variation in the 5-HT transporter gene cause?
–Depression
–Anxiety
What 3 factors mediate the impact of having short alleles in the 5-HT transporter gene?
–Social support
–Poverty
–Childhood maltreatment
What 3 things can environment do to a gene?
- Modify
- Add to
- Inhibit
Foetus
12 weeks after conception until birth
Neonate
Infant less than a month old
What indirect methods are used to study prenatal development?
- Comparative
- Autopsy
- Neonates
What direct methods are used to study prenatal development?
- Foetal ultrasound
- fMRI
- MEC
What 3 things can we record using fetal ultrasound?
- Heartbeat
- Movement
- Behaviour
Synaptogenesis
Building of synapses between nerve cells
Apoptosis
Programmed cell death
Ectoderm (2)
- Outermost germ layer of an embryo
- Develops into CNS and other structures
Neural plate (2)
- Thickening of endoderm cells
- Will become brain
Neural tube (2)
- Hollow structure in embryo
- Will become brain and spinal column
What complex tasks is the cerebral cortex associated with? (5)
- Memory
- Language
- Thought
- Integration of movement
- Integration of senses
When does the cerebral cortex start to develop, and what does this mean?
–About 9 weeks
–Mvmts before then reflexive
What happens to the cerebral cortex at around 6 months?
–Differentiation of frontal, parietal, and occipital lobes
2. Inhibition
3. Reorganization
What is inhibition?
Brain can modify movement, not just cause it -> more refined
What is myelination? (4)
- Fatty insulator around nerve fibres
- Prevents leakage of messages
- Faster & more efficient
- Starts in 6 months post-conception and continues into adulthood
What can the foetus do around 24 weeks? (3)
- Learning
- Respond to environment
- Habituation
What does a foetus do around 34 weeks?
- Behaviour more organised
- Rest and activity
- Quiet sleep and active sleep
What does a foetus do around 38 weeks and what is it affected by? (2+1)
- More inhibitory pathways -> less movement/active sleep
- Peak of activity when mother asleep, lull in early morning
- Affected by environmental factors
What reflexes can foetuses do in response to touch? (5)
- Move when lips touched
- Grasp
- Curl toes
- Move toward touch on face
- Touch own body and cord
Chemosensory system
Taste and smell
Give 3 examples of types of molecules that can get into amniotic fluid and fetal blood
- Perfume
- Cigarette smoke
- Diet
What shows foetuses prefer sweet substances over bitter ones?
Fetus will swallow amniotic fluid more frequently if it contains sweet substances
What neonate studies show babies prefer smells they’ve encountered in the womb?
Turn head in direction of odorant’s that were present in the mother’s diet
What do foetuses do if exposed to alcohol in the womb?
Swallow more :(
Vestibular system
Balance and orientation
What’s one possible explanation for why rocking babies sends them to sleep?
Simulates movement of mother, and foetus would usually move less when mother active
What are 3 potential effects of rocking incubators?
–Weight gain
–Visual responsiveness
–Language development
What is vision like for foetuses?
Not much
No light-dark contrast
No edges
How does the visual system develop in the womb? (3)
- Optic nerve
- Optic nerve “crosses”–lets visual info be integrated
- 6 stripes–that deal with different types of visual info–appear
How is the visual cortex organised?
Like a map of each retina!!!
What do the brain areas around the visual cortex do?
Interpret sensory information
What is auditory stimulation like for a foetus? (4)
–Respond between 26-27 weeks
–Bass
–Loudness
–Mother’s voice
What shows that 35 weeks marks an important advance in learning activity? (2)
–Foetuses habituate and dishabituate to low-intensity auditory stimulation at this age
–Habituation variable before that age and no dishabituation
How have we studied whether prenates prefer their mother’s voice? (4)
- Move more when mother speaking vs a stranger 2 hours after birth
- Infants sucked to play recording of mother’s voice more than unfamiliar voice
- Brain activity
- Preterm don’t show as much preference
What shows neonates have language preferences? (3)
- Can tell difference between mother’s language and others 3 days after birth
- 2 day olds have shown preference for mother’s language over foreign language
- Told story in womb -> as neonate, sucked to hear it more than new story
What aspects of speech can neonates tell apart?
- Rhythm
- Vowel sounds
What % of congenital defects are accounted for by genes alone?
10-15%
What % of congenital defects are accounted for by environment alone?
10%
What % of congenital defects are accounted for by by gene x environment interactions?
75-80%
DNA methylation
Addition of methyl groups to DNA from ageing father’s sperm
Effects of fetal alcohol syndrome (3)
- Physical
- Cognitive
- Behavioural
Effects of environmental tobacco smoke (ETS) on fetus (5)
- Weigh less
- Perinatal complications
- Attention
- Visuoperceptual processing
- Speech processing
Developmental programming
Hypothesis that prenatal conditions have detrimental effects on health in adulthood
What effects does maternal stress have on the foetus? (3)
- Low levels cause maturation of: information processing, mental and motor
- But high levels may not have the same impact
- May exacerbate other factors.
Give examples of continuity between before and after birth.
- Reflexes
- Low HR -> less crying
- Fetal body movements linked to crying
- Higher & less predictable fetal mvmt -> more fussiness
