PSYC 1002 Chapter Notes - Chapter 11: Prenatal Development, Zygote, Placenta
2 May 2018
School
Department
Course
Professor
PSYC 1002
Chapter 11: Human Development across the Life Span
• Development is the sequence of age-related changes that occur as a person progresses
from conception to death
• Reasonably orderly, cumulative process that includes both the biological and behavioral
changes that take place as people grow older
• Physical – changes in the individual associated with biological or maturation changes
• Cognitive – changes in the individual associated with mental abilities
• Social and Emotional – changes in the individual regarding the idiidual’s emotions and
connection with others
Progress before Birth: Prenatal Development:
• Development begins with conception; when fertilization creates a zygote, a one-celled
organism formed by the union of a sperm and an egg; all of the other cells in your body
developed from this single cell
• Each of your cells contains enduring messages from your parents carried on the
chromosomes that lie within its nucleus
• Each chromosome houses many genes, the functional units in hereditary transmission
• Prenatal period: extends from conception to birth, usually nine months of pregnancy
• Germinal Stage:
o First phase of prenatal development (weeks 1 & 2)
o Begins when a zygote is created through fertilization
o Within 36 hours, rapid cell division begins and the zygote becomes a microscopic
mass of multiplying cells
o This ass of ells slol igates alog the othe’s fallopia tue to the
uterine cavity
o On about the seventh day, the cell mass begins to implant itself in the uterine
wall
o Many zygotes are rejected at this point, one in five pregnancies end with the
woman never being aware that conception has occurred
o During the implantation process, the placenta begins to form
o Placenta: is a structure that allows oxygen and nutrients to pass into the fetus
fo the othe’s loodstea, ad odil astes to pass out to the othe
o This critical exchange takes place across thin membranes that block the passage
of blood cells, keeping the fetal and maternal bloodstreams separate
• Embryonic Stage:
o Second stage of prenatal development (Week 2 – 2 months)
o Vital organs and bodily systems begin to form in the developing organism
(embryo)
find more resources at oneclass.com
find more resources at oneclass.com
o Structures such as the heart, spine, and brain emerge gradually as cell division
becomes more specialized
o Starts to look human (arms, legs, hands, feet, fingers, toes, eyes, and ears are
already noticeable)
o Very vulnerable stage
• Fetal Stage
o Third stage of prenatal development (2 months – birth)
o Rapid body growth; bones & muscles begin to form
o Capable of physical movements as skeletal structures harden
o Organs mature
o During the final three months of the prenatal period, brain cells multiply at a
brisk pace
o A layer of fat is deposited under the skin to provide insulation, and the
respiratory and digestive systems mature
The age of viability: the age at which a baby can survive in the event of premature birth. (22-26
weeks)
Environmental factors and Prenatal Development:
• Because the developing organism and its mother are linked through the placenta, a
othe’s eatig haits, dug use, ad phsial health, can affect prenatal development
and have long-term health consequences
• Drugs consumed by a pregnant woman can pass through the membrane of the placenta
• Teratogens: any external agents like; drugs or viruses, that can harm an embryo or fetus
Maternal Drug Use:
• Babies of heroin users are born addicted to narcotics, have an increased risk of early
death (prematurity), birth defects, respiratory difficulties, and problems associated with
their addiction
• Prenatal exposure to cocaine is associated with increased risk of birth complications and
a variety of cognitive deficits that are apparent in childhood
• Problems can also be caused by a great variety of drugs prescribed for legitimate
medical reasons, and even some over-the-counter drugs
• Fetal alcohol syndrome: a collection of congenital (inborn) problems associated with
excessive alcohol use during pregnancy
• Typical problems include: microcephaly (a small head), heart defects, irritability,
hyperactivity, and delayed mental and motor development
• Fetal alcohol syndrome is the most common known cause of intellectual disability and it
is related to an increased incidence of difficulties in school, depression, suicide, drug
problems, and criminal behavior in adolescence and adulthood
• Tobacco use during pregnancy is also hazardous to prenatal development, increases
othe’s isk fo isaiage, stillith, ad peatuit, ad eos’ isk fo sudde
infant death syndrome
find more resources at oneclass.com
find more resources at oneclass.com
• Prenatal exposure to tobacco is also associated with slower than average cognitive
development, attention deficits, hyperactivity, and conduct problems
Maternal Illness and Exposure to Toxins:
• The fetus is largely defenseless against infections because its immune system matures
relatively late in the prenatal period
• The placenta screens out most infectious agents, but not all, many maternal illnesses
can interfere with prenatal development
• Diseases such as rubella, syphilis, cholera, smallpox, mumps, and even severe cases of
the flu can be hazardous to the fetus
• The HIV virus that causes AIDS can be transmitted by pregnant women to their
offspring, transmission of AIDS may occur prenatally through the placenta, during
delivery, or through breastfeeding
• Environmental toxins can have an impact on the fetus, prenatal exposure to air pollution
has been linked to impairments in cognitive development at age 5
Maternal Nutrition and Emotions:
• The developing fetus needs a variety of essential nutrients, severe maternal
malnutrition increases the risk of birth complications and neurological defects for the
newborn
Motor Development: the progression of muscular coordination required for physical activities,
basic motor skills include; grasping and reaching for objects, manipulating objects, sitting up,
crawling, walking, and running.
Basic Principles:
• Cephalocaudal trend: the head-to-foot direction of motor development, children tend
to gain control over the upper part of their bodies before the lower part
• Proximodistal trend: the centre-outward direction of motor development, children gain
control over their torso before their extremities (twist body before they learn to extend
arms)
• Maturation – deelopet that eflets the gadual ufoldig of oe’s geeti luepit
Developmental norms: indicate the median age at which individuals display various behaviours
and abilities
• Deelopetal os ae useful ehaks as log as paets do’t epect their
children to progress exactly at the pace specified in the norms
• Some parents become unnecessarily alarmed when their children fall behind
developmental norms, variations from the typical age of accomplishment are entirely
normal
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The age of viability: the age at which a baby can survive in the event of premature birth. (22-26 weeks) Maternal nutrition and emotions: the developing fetus needs a variety of essential nutrients, severe maternal malnutrition increases the risk of birth complications and neurological defects for the newborn. Motor development: the progression of muscular coordination required for physical activities, basic motor skills include; grasping and reaching for objects, manipulating objects, sitting up, crawling, walking, and running. Developmental norms: indicate the median age at which individuals display various behaviours and abilities: de(cid:448)elop(cid:373)e(cid:374)tal (cid:374)o(cid:396)(cid:373)s a(cid:396)e useful (cid:271)e(cid:374)(cid:272)h(cid:373)a(cid:396)ks as lo(cid:374)g as pa(cid:396)e(cid:374)ts do(cid:374)"t e(cid:454)pect their children to progress exactly at the pace specified in the norms. Some parents become unnecessarily alarmed when their children fall behind developmental norms, variations from the typical age of accomplishment are entirely normal. Attachment: the close emotional bonds of affection that develop between infants and their caregivers.
