D&E SUMMARIES Page !1 of !87
Developmental psychology – Chapter 2 - Prenatal development
Conception
Gametes: Single cell that resulted from the union of two highly specialized cells, each
one contains only half of the genetic material found in other cells
Meiosis: Cell division in which eggs and sperm receive only one member from each of
the 23 chromosome pairs contained in all other cells of the body
- If act of sexual intercourse takes place near the time egg is released
(conception), unit of sperm and egg will be possible
- Sperm must travel for about 6 hours Survival of the fittest
Zygote: Fertilized egg, from fallopian tube to womb (Full complement of human genetic
material, 23 chro. from mother, 23 from father)
Developmental processes
1. Mitosis: First cell division, happens 12 hours after fertilization
2. Cell migration: Movement of newly formed cells away from their point of origin
3. Cell differentiation: Cells start to specialize in terms of both structure and
function
Embryonic stem cells: All of the embryos cells (equivalent and interchangeable, no
fixed fate or function)
4. Apoptosis: Selective death of certain cells (Apparent in hand development,
death of cells in between ridges)
- Presence or absence of androgens causes either development of male or female
genitalia (Around 8th week)
Early development
Identical twins: Mostly develop by the 4th day after conception, result from splitting in a
half of the inner cell mass (both exactly same genetic makeup)
Fraternal twins: Two eggs happen to be released from the ovary into the fallopian tube
and both are fertilized
- By end of 1st week following fertilization zygote embeds itself in uterine lining and
become dependent of mother
Amniotic sac: Membrane filled with clear, watery, fluid in which foetus floats, protective
buffer
placenta: Enable embryo develop, permits exchange of materials carried in
bloodstream of the foetus and its mother, prevents mixing of blood systems of mother
and child, semipermeable (Some elements can pass and some not), defensive barrier
against host of dangerous toxins
- During 2nd week inner cell mass folds itself into three layers (Each with diff.
developmental destiny) Top: nervous system, nails, teeth, inner ear..
- Middle: Muscles, bones, circulatory system
,D&E SUMMARIES Page !2 of !87
- Bottom: Digestive system, lungs, glands
Neural tube: Develop into brain and spinal cord
Umbilical cord: Blood vessels running from placenta to embryo, contained in umb.
Cord
Prenatal development
Cephalocaudal development: Earlier development takes place at more rapid pace
than later development, areas nearer the head develop earlier than those farther away
- At 4 weeks after conception: Primitive heart visible, moving and stretching,
- 5 ½: Nose, mouth and palate develop into separate structures
- 9th weeks: Head overwhelms rest of body, internal organs are present, sexual
differentiation has started
- 11th weeks: heart has basic adult structure
- Last 5 months: Growth of lower part of body, increasing movement
- 18th week: fine hair, components of facial expression,
- 28th week: Brain and lungs developed, eyes can open and move
Fetal behavior
Movement:
- Child starts moving from 5 or 6 weeks after conception
- Around week 7 hiccups start (removing air from stomach for more room for milk (theory))
- Swallowing effect, foetus swallows amniotic fluid (tongue movement for drinking and
swallowing and digestive system develop)
- Movement of limbs, wiggling fingers
- Practicing for breathing outside the womb by pulling small amounts of amniotic fluid into
lungs and expelling them
Behavioral cycles:
- Periods of inactivity gradually begin to occur
Rest- activity cycles (Bursts off high activity alternating with little or no activity)
- Near end of pregnancy fetus three-fourths of time sleeping (REM sleep)
Fetal experience
Sight and touch
- Visual experience minimal
- Experience of tactile stimulation as result of own activity
- Respond to maternal movement Vestibular system (Sensory apparatus in inner ear)
is functioning before birth
Taste
- Amniotic fluids contains variety of flowers (Fetus can detect)
- Fetus has sweet tooth
Smell
- Amniotic fluid takes on odors from what mother has eaten
,D&E SUMMARIES Page !3 of !87
- Smells can be transmitted through liquid
Hearing
- Noise level in womb about 70-95 decibels (Loud)
- Fetus also perceives sounds outside the mother
Fetal learning
- Fetuses (30 weeks) show habituation and dishabituation to both visual and auditory
stimuli
- Newborns remember fetal experience after birth (Scent of amniotic fluid)
Experiences in the womb can lead to long-lasting taste preference
- Fetus just learns about mothers voice and general patterns of her language (not any
specific content)
Hazards to prenatal development
Teratogens
Teratogens: Environmental agents that can harm the fetus, timing is a crucial factor in severity
of effects, many can only cause damage when they are present during sensitive period,
amount of duration of exposure
Major organ system most vulnerable to damage at time when basic structures are
formed
Look at figure 2.14 (p.61) in book
Dose-response relation: The greater fetus exposure to potential teratogen, the more likely that
fetus will suffer damage and the more severe any damage is likely to be
- Effects can vary according to individual differences in genetic susceptibility
Drugs
- Harmful, just take under supervision of physician
Antidepressants
- Depression during pregnancy is problematic (For both mother and child)
- SSRI’s are very harmful (cardiac malformations)
Opioids
- Use of opioid prescription medications harmful
Illegal drugs
Cigarette smoking
- Baby gets less oxygen
- Linked with higher risk of sudden infant death syndrome
Alcohol
- Alcohol crosses placenta into fetus bloodstream and amniotic fluid, fetus has no ability to
remove alcohol
, D&E SUMMARIES Page !4 of !87
- Maternal drinking can result in Fetal alcohol spectrum disorder (Facial deformities,
attention problems, hyperactivity)
Environmental Pollutants
Maternal factors
Age
- Very old and very young can be dangerous
- Children born by older mothers at heightened risk of ASD
Nutrition
- Inadequate diets can lead to deprivation in child (nutritionally)
- Lack of folic acid can lead to child with neural tube
- General malnutrition affects growth of brain
Disease
- Some diseases dangerous for child
- STIs quite hazardous for fetus (Genital herpes, HIV)
- Maternal flu and other types of infections may interact with genetic factors to lead to
mental illness
- Zika-virus
Maternal emotional state
- Prenatal maternal stress linked to postnatal behavior problems
- Genetic factors also link both maternal stress and postnatal outcomes
The birth experience
- 38 weeks after conception
- Typically baby has already contributed to process by rotating itself into normal head-
down position
- Birth is not painful for newborn Mothers pain come from tissues being stretched, baby
is squeezed
- Squeezing has benefits: Forces amniotic fluid out of lungs for baby to grasp air (strong
cry is good)
State of arousal
State: Continuum of arousal, ranging from deep sleep to intnse activity
Sleep
Rapid eye movement (REM) sleep: Active sleep state associated with dreaming in adults
- Characterized by quick, jerky eye movements under closed lids
Non-REM sleep: Quite sleep state characterized by absence of motor activity or eye
movements
- Regular slow brain waves, breathing and heart rate
- REM sleep constitutes fully 50% of newborns total sleep time Declines rapidly to only
20% by 3/4 years
Developmental psychology – Chapter 2 - Prenatal development
Conception
Gametes: Single cell that resulted from the union of two highly specialized cells, each
one contains only half of the genetic material found in other cells
Meiosis: Cell division in which eggs and sperm receive only one member from each of
the 23 chromosome pairs contained in all other cells of the body
- If act of sexual intercourse takes place near the time egg is released
(conception), unit of sperm and egg will be possible
- Sperm must travel for about 6 hours Survival of the fittest
Zygote: Fertilized egg, from fallopian tube to womb (Full complement of human genetic
material, 23 chro. from mother, 23 from father)
Developmental processes
1. Mitosis: First cell division, happens 12 hours after fertilization
2. Cell migration: Movement of newly formed cells away from their point of origin
3. Cell differentiation: Cells start to specialize in terms of both structure and
function
Embryonic stem cells: All of the embryos cells (equivalent and interchangeable, no
fixed fate or function)
4. Apoptosis: Selective death of certain cells (Apparent in hand development,
death of cells in between ridges)
- Presence or absence of androgens causes either development of male or female
genitalia (Around 8th week)
Early development
Identical twins: Mostly develop by the 4th day after conception, result from splitting in a
half of the inner cell mass (both exactly same genetic makeup)
Fraternal twins: Two eggs happen to be released from the ovary into the fallopian tube
and both are fertilized
- By end of 1st week following fertilization zygote embeds itself in uterine lining and
become dependent of mother
Amniotic sac: Membrane filled with clear, watery, fluid in which foetus floats, protective
buffer
placenta: Enable embryo develop, permits exchange of materials carried in
bloodstream of the foetus and its mother, prevents mixing of blood systems of mother
and child, semipermeable (Some elements can pass and some not), defensive barrier
against host of dangerous toxins
- During 2nd week inner cell mass folds itself into three layers (Each with diff.
developmental destiny) Top: nervous system, nails, teeth, inner ear..
- Middle: Muscles, bones, circulatory system
,D&E SUMMARIES Page !2 of !87
- Bottom: Digestive system, lungs, glands
Neural tube: Develop into brain and spinal cord
Umbilical cord: Blood vessels running from placenta to embryo, contained in umb.
Cord
Prenatal development
Cephalocaudal development: Earlier development takes place at more rapid pace
than later development, areas nearer the head develop earlier than those farther away
- At 4 weeks after conception: Primitive heart visible, moving and stretching,
- 5 ½: Nose, mouth and palate develop into separate structures
- 9th weeks: Head overwhelms rest of body, internal organs are present, sexual
differentiation has started
- 11th weeks: heart has basic adult structure
- Last 5 months: Growth of lower part of body, increasing movement
- 18th week: fine hair, components of facial expression,
- 28th week: Brain and lungs developed, eyes can open and move
Fetal behavior
Movement:
- Child starts moving from 5 or 6 weeks after conception
- Around week 7 hiccups start (removing air from stomach for more room for milk (theory))
- Swallowing effect, foetus swallows amniotic fluid (tongue movement for drinking and
swallowing and digestive system develop)
- Movement of limbs, wiggling fingers
- Practicing for breathing outside the womb by pulling small amounts of amniotic fluid into
lungs and expelling them
Behavioral cycles:
- Periods of inactivity gradually begin to occur
Rest- activity cycles (Bursts off high activity alternating with little or no activity)
- Near end of pregnancy fetus three-fourths of time sleeping (REM sleep)
Fetal experience
Sight and touch
- Visual experience minimal
- Experience of tactile stimulation as result of own activity
- Respond to maternal movement Vestibular system (Sensory apparatus in inner ear)
is functioning before birth
Taste
- Amniotic fluids contains variety of flowers (Fetus can detect)
- Fetus has sweet tooth
Smell
- Amniotic fluid takes on odors from what mother has eaten
,D&E SUMMARIES Page !3 of !87
- Smells can be transmitted through liquid
Hearing
- Noise level in womb about 70-95 decibels (Loud)
- Fetus also perceives sounds outside the mother
Fetal learning
- Fetuses (30 weeks) show habituation and dishabituation to both visual and auditory
stimuli
- Newborns remember fetal experience after birth (Scent of amniotic fluid)
Experiences in the womb can lead to long-lasting taste preference
- Fetus just learns about mothers voice and general patterns of her language (not any
specific content)
Hazards to prenatal development
Teratogens
Teratogens: Environmental agents that can harm the fetus, timing is a crucial factor in severity
of effects, many can only cause damage when they are present during sensitive period,
amount of duration of exposure
Major organ system most vulnerable to damage at time when basic structures are
formed
Look at figure 2.14 (p.61) in book
Dose-response relation: The greater fetus exposure to potential teratogen, the more likely that
fetus will suffer damage and the more severe any damage is likely to be
- Effects can vary according to individual differences in genetic susceptibility
Drugs
- Harmful, just take under supervision of physician
Antidepressants
- Depression during pregnancy is problematic (For both mother and child)
- SSRI’s are very harmful (cardiac malformations)
Opioids
- Use of opioid prescription medications harmful
Illegal drugs
Cigarette smoking
- Baby gets less oxygen
- Linked with higher risk of sudden infant death syndrome
Alcohol
- Alcohol crosses placenta into fetus bloodstream and amniotic fluid, fetus has no ability to
remove alcohol
, D&E SUMMARIES Page !4 of !87
- Maternal drinking can result in Fetal alcohol spectrum disorder (Facial deformities,
attention problems, hyperactivity)
Environmental Pollutants
Maternal factors
Age
- Very old and very young can be dangerous
- Children born by older mothers at heightened risk of ASD
Nutrition
- Inadequate diets can lead to deprivation in child (nutritionally)
- Lack of folic acid can lead to child with neural tube
- General malnutrition affects growth of brain
Disease
- Some diseases dangerous for child
- STIs quite hazardous for fetus (Genital herpes, HIV)
- Maternal flu and other types of infections may interact with genetic factors to lead to
mental illness
- Zika-virus
Maternal emotional state
- Prenatal maternal stress linked to postnatal behavior problems
- Genetic factors also link both maternal stress and postnatal outcomes
The birth experience
- 38 weeks after conception
- Typically baby has already contributed to process by rotating itself into normal head-
down position
- Birth is not painful for newborn Mothers pain come from tissues being stretched, baby
is squeezed
- Squeezing has benefits: Forces amniotic fluid out of lungs for baby to grasp air (strong
cry is good)
State of arousal
State: Continuum of arousal, ranging from deep sleep to intnse activity
Sleep
Rapid eye movement (REM) sleep: Active sleep state associated with dreaming in adults
- Characterized by quick, jerky eye movements under closed lids
Non-REM sleep: Quite sleep state characterized by absence of motor activity or eye
movements
- Regular slow brain waves, breathing and heart rate
- REM sleep constitutes fully 50% of newborns total sleep time Declines rapidly to only
20% by 3/4 years
