Psychology 30
Concept Web

Looking through the eyes of the
developing person …

Looking through the eyes of the
systems of support …
Unit Objectives





To understand the issues and challenges in
becoming a parent.
To understand the biological changes from
conception to birth.
To understand the cognitive changes from
conception to birth.
To understand the socioemotional changes
from conception to birth.
To understand the issues, challenges and
support systems from the perspective of
microsystems, exosystems, and
macrosystems of support.
2.1 Unit Overview: Human
development from conception to birth

Video:
 National Geographic’s In The Womb
Physical Development:





The germinal period is the first two weeks of
development.
This period is characterized by rapid cell division, the
beginning of cell differentiation, and implantation of the
blastocyst into the uterine wall.
By approximately one week after conception, the zygote
is composed of 100 to 150 cells.
The differentiation of cells commences and the zygote
becomes differentiated into two layers: The blastocyst is
the inner layer of cells that later develop into the embryo;
the trophoblast is the outer layers of cells that later
provides nutrition and support for the embryo.
Implantation of the zygote into the uterine wall takes place
about 10 days after conception (Santrock, 1999, p. 103).
Physical Development:




The embryonic period is the period of prenatal
development that occurs from two to eight weeks
after conception.
The embryo's endoderm, the inner layer or cells,
primarily produces internal body parts such as the
respiratory and digestive systems. T
he middle layer of cells, called the mesoderm, will
become the circulatory system, bones, muscle,
excretory system, and reproductive system.
The outer layer of cells, the ectoderm, will become
the nervous system, the sensory receptors (eyes,
nose, ears), and skin. As the embryo develops so
too does the placenta, the umbilical cord and the
amnion (fluid-filled sac) (Santrock, 1999, p. 103).
Physical Development:
The fetal period is the period of development that begins two
months after conception and lasts for seven months, on the
average.
 Three months after conception the fetus is 10 centimetres long
and weighs approximately 60 grams.

 It has become active, moving its arms and legs, opening and closing its
mouth, and moving its head.
 The face, forehead, eyelids, nose, and chin are all distinguishable, as
are the arms, hands and legs.
At four months, a growth spurt occurs in the fetus' lower parts.
By the end of the fifth month the toenails and fingernails have
formed and the fetus is more active.
 By the end of the sixth month the eyes and eyelids have
completely formed, a grasping reflex is present and irregular
breathing occurs.
 In the last two months, fatty tissues develop and the functioning
of various organs such as the heart and kidneys steps up
(Santrock, 1999, p. 103).


Cognitive Development:




Some simple aspects of the functioning of the human
nervous system appear very early.
Indeed the blood circulation system and the nervous
system are the first to function in embryonic life, with
heartbeat commencing in the third week following
conception.
By the second month, an avoidance reaction, the
withdrawal of the hand region by contraction of the
neck muscles, occurs if an unpleasant stimulus is
applied to the embryonic upper lip.
These developments imply that simple arc reflexes
are already differentiated at this stage, with
appropriate synaptic connections and interneuronal
activity being brought into play in order to coordinate
muscular movements (Rose, 1989, p. 192).
Temperament/Personality
Development:



Every individual is born with a distinct,
genetically-based set of psychological
tendencies, or dispositions.
These tendencies, which together are called
temperament, affect and shape virtually every
aspect of the individual's developing
personality.
Temperament, and therefore personality, is not
merely genetic: it begins in the multitude of
genetic instructions that guide the
development of the brain and then is affected
by the prenatal environment (Berger, 2000, p.
219).
What are the critical periods in
prenatal development?
Body System
Especially Sensitive
Development up to …
Central nervous
system/Brain
Heart
4th to 8th weeks
5th to 9th weeks
Postnatal, through to
adulthood
12th week
Upper limbs
6th to 10th weeks
12th week
Eyes
6th to 10 weeks
Term
Lower limbs
6th to 10th weeks
12th week
Teeth
9th to 11th weeks
Term
Palate
9th to 11th weeks
16th week
External genitalia
9th to 11th weeks
Term
Ears
6th to 11th weeks
13th week
What are some alternative
methods of conception?

In vitro fertilization (IVF): In this procedure,
ova are surgically removed from the
ovaries, fertilized by sperm in the
laboratory, and allowed to divide until the
16- or 32-cell stage. The resulting cells are
then inserted into the uterus, where about
one cell cluster in seven successfully
implants, develops and becomes a healthy
baby. The success rate is just under 20
percent (Berger, 2000, p. 73).
What are some alternative
methods of conception?
Gamete intrafallopian transfer (GIFT). A
doctor inserts eggs and sperm directly into
a woman’s fallopian tube. The success
rate is almost 30 percent (Santrock, 1999,
p. 69).
 Intrauterine (artificial) insemination. Frozen
sperm, from the husband or an unknown
donor, is placed directly into the uterus,
bypassing the cervix and upper
vagina. The success rate is 10 percent
(Santrock, 1999, p. 69).

What are some alternative
methods of conception?


Zygote intrafallopian transfer. This involves a
two-step procedure. First, eggs are fertilized
in the laboratory. Then, any resulting zygotes
are transferred to a fallopian tube. The
success rate is approximately 25 percent
(Santrock, 1999, p. 69).
Intracytoplasmic sperm injection. A doctor
uses a microscopic pipette to inject a single
sperm from a man’s ejaculate into an
egg. The zygote is returned to the woman’s
body. The success rate is approximately 25
percent (Santrock, 1999, p. 69).
What are some alternative
methods of conception?

Ovum donation has two possibilities: In
one version, a woman volunteers to be a
surrogate mother; usually she is artificially
inseminated with sperm from an infertile
woman’s husband and carries the baby to
term. In another version, some of a donor
woman’s ova are removed and artificially
inseminated with a man’s sperm; then the
cluster of cells is inserted into his own
wife’s uterus (Berger, 2000, p. 73).
What are some influences that can have a negative
impact on healthy prenatal development?
Harmful substances such as drugs or
radiation that invade the womb and result
in birth defects are called teratogens.
 Teratogens are especially damaging in the
embryonic stage because it is a critical
period in prenatal development.
 Later, during the fetal stage, the
environment provided by the mother affects
the baby’s size, behaviour, intelligence and
health, rather than the formation of organs
and limbs (Bernstein and Nash, 1999, p.
333).

Environment
Radiation, chemicals, and other hazards in the
environment can endanger the fetus.
 Chromosomal abnormalities are higher among the
offspring of fathers exposed to high levels of radiation in
their occupations.
 Environmental pollutants and toxic wastes are also
sources of danger to unborn children. Among the
dangerous pollutants and wastes are carbon monoxide,
mercury and lead.
 Another environmental concern is toxoplasmosis, a mild
infection that causes cold-like symptoms or no apparent
illness in adults, but can cause eye defects, brain defects,
and premature birth. Cats are common carriers of
toxoplasmosis, especially outdoor cats who eat raw
meat. The expectant mother may pick up the virus
through the cat litter box (Santrock, 1999, p. 100).

Mother’s age



Two time periods are of special
interest: adolescence and the thirties and beyond.
Infants born to adolescents are often
premature. The mortality rate of infants born to
adolescent mothers is double that of infants born to
mothers in their twenties.
Down Syndrome, a form of mental retardation, is
related to the mother's age. By age 40, the
probability is slightly over 1 in 100. By age 50, it is
almost 1 in 10. The risk is also higher before age
18. Women also have more difficulty in becoming
pregnant after the age of 30 (Santrock, 1999, p. 93).
Nutrition



Another common reason for slow fetal growth, and
hence low birth weight, is maternal malnutrition, a
problem that has many specific causes.
Women who begin pregnancy underweight, eat
poorly during pregnancy, and consequently do not
gain at least 1.5 kilograms per month in the second
and third trimesters run a much higher risk than
others of having a low birth weight infant.
Indeed, women who gain less than seven kilograms,
even if they are non-smokers who begin pregnancy
overweight, still have a higher risk of preterm and
smaller babies than those who gain at least seven
kilograms (Berger, 2000, p. 119).
Infections and Diseases




Maternal diseases and infections can produce
defects by crossing the placental barrier.
For example, the greatest damage to the fetus from
the mother contracting German measles occurs
during the third and fourth weeks of pregnancy.
Syphilis is more damaging later in prenatal
development, four months or more after
conception. Rather than affecting organ
development as Rubella does, syphilis damages
organs after they have formed.
The importance of the mother's health to the health
of her offspring is nowhere better exemplified than
when the mother is infected with HIV (Santrock,
1999, p. 98).
Drugs



Drugs include tobacco, alcohol, prescription, or illegal drugs.
For example, the effects of thalidomide during the fourth
week of development had devastating effects.
Heavy drinking by an expectant mother can also be
devastating. Fetal alcohol syndrome is a cluster of
abnormalities that appear in the offspring of mothers who
drink alcohol heavily during pregnancy. The abnormalities
include facial deformities and defective limbs, face and
heart. Most of these children are below average in
intelligence. In one study, however, even mothers who drank
moderately during pregnancy had babies who were less
attentive and alert, with the effects still present at four years
of age.
Drugs


Cigarette smoking by pregnant women can also adversely
influence prenatal development, birth and postnatal
development. Fetal and neonatal deaths are higher among
smoking mothers. Also prevalent are a higher incidence of
preterm births and lower birth weights. Respiratory problems
and sudden infant death syndrome are also more common
among the offspring of mothers who smoked during
pregnancy.
Tranquilizers taken during the first three months may cause
cleft palate or other congenital malformations. Mothers who
take large amounts of barbituates may have babies who are
addicted or may exhibit tremors, restlessness, and irritability
(Santrock, 1999, p. 98).
Poverty
Compared with women of higher socioeconomic status,
pregnant women at the bottom of the economic ladder are more
likely to be ill, malnourished, teenaged, and stressed.
 Physical difficulty like malfunction of the placenta or the
umbilical cord is likely when pregnancies are closely spaced
and close spacing correlates with poverty.
 Poverty helps explain the wide national and international
variations in the following statistics:

 Of the more than 25 million low birth weight infants born worldwide each
year the overwhelming majority are in developing countries.
 Developing countries in the same geographic region, with similar ethnic
populations, have markedly different low birth weight rates when they
have different average incomes.
 Within nations, differences in low birth weight rates among ethnic groups
follow socioeconomic differences among those groups.
 Within the United States low birth weight rates in the poorest states are
almost twice those in some richer states (Berger, 2000, p. 120).
Emotional state




The mother's stress can be transmitted to the fetus.
When a pregnant woman experiences intense fears,
anxieties, and other emotions, physiological changes
occur in the fetus. These include changes in
respiration and glandular secretions.
For example, producing adrenaline in response to
fear restricts blood flow to the uterine area and may
deprive the fetus of adequate oxygen.
Also, reassuring the mother of fetal well-being has
positive outcomes for the infants in the study
(Santrock, 1999, p. 93).
What are the factors that
influence the degree of affect?




One crucial factor is the time at which the developing
organism is exposed to a specific teratogen.
Some teratogens cause damage only during specific
days or weeks early in pregnancy, when a particular
part of the body is being formed.
Others can be harmful at any time, but how severe
the damage is depends on when the exposure
occurred. The time of greatest susceptibility is called
the critical period.
Each body structure has its own critical period. As a
general rule, for physical defects the critical period is
the entire prenatal period.
What are the factors that
influence the degree of affect?
A second important factor is the dose and/or frequency of
exposure to a teratogen. For most teratogens, experts
are reluctant to specify a threshold below which the
substance is safe. One reason is that many teratogens
have an interaction effect; that is, one poison intensifies
the effects of another.
 A third factor that determines whether a specific teratogen
will be harmful, and to what extent, is the developing
organism's genes. In some cases, genetic vulnerability is
related to the sex of the developing organism. Generally,
male embryos (XY) and fetuses are at a greater risk than
female in that male embryos are more often aborted
spontaneously. In addition, newborn boys have more
birth defects, and older boys have more learning
disabilities and other problems caused by behavioural
teratogens (Berger, 2000, pp. 106-109).
