Prenatal Development and the Newborn

Prenatal Development and the Newborn
 “Prenatal” = conception  birth
Conception Process
 Female releases egg (she is born with all she’ll have, but will release 1 in 5,000)
 200 million sperm cells released (sperm cells are produced, beginning in puberty)
 Just one gets in
o Does so by releasing a digestive enzyme to eat away egg protective coat
o Once one is in, egg pulls it in, and will not allow others.
 Zygote – fertilized egg
Prenatal Development
 ½ of zygotes do not make it passed 2 weeks.
 Cells divide – by 1st week it is 100 cells.
 Cells then begin to differentiate – divide tasks of development.
 After 10 days, the cells attach to uterine wall
o Outer cells become placenta
o Inner cells become the embryo
o Embryo – developing human organism from 2 weeks through 2nd month.
o (Releases hormone to stop uterus from shedding lining – period)
 9 weeks – looks unmistakably human (fetus – 9 weeks  birth)
o 6 months – stomach developed and functions (lucky for preemies)
 Also, can hear mother’s muffled voice (preferred from birth)
 Play Mind Clip - Teratogens
 Teratogens – harmful agents such as viruses or drugs that reach the embryo or
fetus during prenatal development. (cause birth defects)
o Heroin, nicotine, AIDS
o Embryonic stages – major structural damage
o Fetal stage – usually stunt growth or interfere with organ functioning
 Fetal Alcohol Syndrome (FAS) – marked by small, misproportional head and
lifelong brain abnormalities.
o Overall likelihood – 1 in 750 infants
o Obviously, alcoholics make it more likely - 4 in 10 babies born to
alcoholic mothers
o 1 drinking binge can kill millions of fetal brain cells
o There is no known safe amount of alcohol consumption
Science still not conclusive on role of a woman’s psychological state during
o Some results say stress can lead to delayed motor development, increased
emotionality, learning deficits, and depression.
Competent Newborn
 Babies come equipped with reflexes suited for survival.
o Grasp reflex
o Babinski reflex – sole of foot touched, toes fan, turn inward
o Stepping reflex
o Moro reflex – startle response – infant arches back, throws back head,
flings out arms and legs – then rapidly closes arms and legs to body.
o Rooting reflex – if head touched, baby turns, searches, and sucks
o Visual tracking
Crying – humans predisposed to find it unpleasant, relieving it is reward.
How do we study newborns? How do we know what they like?
o He have to become behaviorists – let the behaviors do the talking.
o Habituation – decreasing responsiveness with repeated stimulation.
 As infants gain familiarity with repeated exposure to a visual
stimulus, their interest wanes and they begin to look away sooner.
What do they like?
o Prefer sights/sounds that facilitate social responsiveness
 Turn head toward human voices
 Smell of mother
 Can find mother’s bra when given 2 choices
 Preferred distance from object 8” – 12”
 Eye contact distance while nursing
 Prefer facial pattern to non-facial pattern
 Prefer bull’s-eye (resembles eye) to blank disc.