Developmental and Educational Psychology
Lecture 1- Prenatal development and attachment
Ch2: 43-70
Ch11: 465-480
Epigenesis the emergence of new structures and functions in the course of development
(proposed by Aristotle)
Conception:
Gametes reproductive cells (egg and sperm) that contain only half the genetic material of all
other body cells
Egg cell and sperm cell merge
Fertilization the fusion of the gametes
- Each gamete has 23 chromosome
- When gametes fuse they form a zygote
Mitosis regular cell division that results in 2 identical cells
Meiosis the formation of gametes
Conception the union of an egg from the mother and a sperm from the father
- The egg moves through the ovaries and out through the fallopian tubes towards the uterus,
releasing a chemical substance which attracts sperm cells towards the egg cell
- In ejactulation almost 500 million sperm released- sperm travels 6 hours to reach the egg-
survival of the fittest situation where only the healthiest/best sperm reach the egg
- When the sperm enters the egg a chemical reaction seals the egg so no more sperm enter
- Zygote fertilized egg cell
Cell migration the movement of newly formed cells away from their point of origin
Cell differentiation cells reach specific destination and serve specific function, the
specialization of cells
- Stem cells are undifferentiated cells
- Embryonic stem cells Embryonic cells which can develop into any type of body cell
Apoptosis cells die (necessary for getting rid of unnecessary cells)- genetically programmed
cell death
Hormones play an important role in sexual differentiation
- androgens (such as testosterone) lead to the development of male genitalia
- steroids (such as glucocorticoids) limit fetal growth and help fetal tissues mature
Zygote (0-2 weeks):
Migration to uterus- most vulnerable stage- 50% of zygotes don’t survive
Cell division (happens twice a day)- first happens 12 hours after conception
Implantation in the uterine wall- cells become a hollow sphere which creates the support system
where embryo forms
hCG Is secreted
Twins occur at this stage
- Identical twinsMonozygotic- zygote splits in 2 forming 2 zygotes- genetically identical
- Fraternal twinsDizygotic- 2 eggs fertilized- comes from 2 different zygotes- same as
siblings genetically
- Triplets can happen different ways
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Embryo (3-8 weeks):
Embryo the developing organism from the 3rd to 8th week of prenatal development
Inner cell mass forms 3 layers- different parts of the body
- Top layer is nervous system, skin, the nails, the teeth, inner, ear and eye lens
- Middle layer is muscles, bones, circulatory system, internal organs
- Bottom layer forms digestive system, lungs, urinary tract and glands
Extremely vulnerable stage- most miscarriages happen at this stage, vulnerable to environmental
influences (teratogens), 15-20% don’t survive
Layers collapse and form neural tube (later spine and brain of baby)
- Neural tube a groove formed in the top layer of differentiated cells in the embryo that
eventually become the brain and spinal cord
Support system develops placenta and umbilical cord and amniotic sac
- Amniotic sac a transparent, fluid filled membrane that surrounds and protects the fetus-
provides even temperatures and cushioning
- Placenta A support organ for the fetus, keeps the circulatory systems of the fetus and
mother separate, but a semi-permeable membrane permits the exchange of some materials
between them (O2 and nutrients, CO2 and waste products)
- Umbilical cord a tube containing the blood vessels connecting the fetus and the placenta
Cephalocaudal development the pattern of growth in which areas near the head develop
earlier that areas further from the head
Fetus (9 weeks- birth):
Fetus the developing
organism from the 9th week
of prenatal development
Further development of
organ and systems
Physical growth, mostly
part of body
(cephalocaudal- development of the head)
90% born healthy -often
after 38 weeks
Prenatal behaviour/sensation:
Despite their very different
environment
(discontinuity), fetuses and children show surprising similarities (continuity)
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Embryo moves at around 5-6 weeks
Week 7 hiccups- theory of burping reflex
Week 10 fetal breathing- amniotic fluid flows in and out of lungs, wake sleep cycle- sleep for
2/3 of the time
Week 12 behaviors of newborn are present- grasping, swallowing, thumb sucking
Prenatal Sensory experiences:
Only some visual stimulation
Lots of tactile movements from moving around
Preference for sweet foods- amniotic fluid takes on flavor and scent of ingested food
Fetus responds to internal and external sounds- should not go to loud places, very loud inside
uterus, fetus responds mainly to mothers voice
Prenatal Learning:
Research only from during 3rd trimester
Animal studies show that babies have a memory for the amniotic fluid scent
- Phylogenetic continuity because of our common evolutionary history, humans share
many characteristics, behaviors and developmental processes with non-human animals,
especially mammals
Research with human newborns- preference for the mothers voice- measured through sucking
pattern- shows habituation
- Habituation a simple form of learning that involves a decrease in response to repeated or
continued stimulation
- Dishabituation the introduction of a new stimulus rekindles interest following habituation
to a repeated stimulus
Harmful influences:
Teratogens environmental influences that can lead to damage to or even death during prenatal
development
- Dose-response relation a relation in which the effect of exposure to an element increases
with the extent of exposure (prenatally, the more exposure a fetus has to a potential teratogen,
the more severe its effects are likely to be)
- Sensitive period the period of time during which a developing organism is most sensitive
to the effects of external factors
- Most damaging during embryonic stage
Mother behavior diet can help development: folic acid (vitamin b- helps folding in stage), other
nutrients (e.g. calcium)
- Harmful: smoking (cigarettes cause most damage), alcohol (results in fetal alcohol spectrum
disorder FASD), drugs (antidepressants, opioids, marijuana)
- FASD fetal alcohol syndrome involves facial deformities, intellectual disabilities, attention
problems, hyperactivity, FAE is term used for those who only display some FAS symptoms.
- Age, Infections (measles/rubella, herpes, influenza, zika virus), mental health (stress
hormones cause greater activity of fetus), depression (more likely post partum depression can
damage attachment with baby), nutrition
External factors which can affect the baby’s development include- toxic metals, pesticides,
synthetic hormones, plastics, herbicides, air pollution