Prenatal Development Flashcards
last reading wang andfeigenson
people make an assuption that people are are result of learning and then born that way
Why study prenatal development
in an Infancy course?
Ilustrates some of the most important
facts of development
– Cell division
– Cell migration
– Cell differentiation
– Also: programmed cell death (apoptosis)
Principles to map facts on to
Illustrates some of the most important
principles of development
– Nature/Nurture
– Critical or sensitive periods
– Continuity/Discontinuity
– The lasting importance of early experience
* Fetal programming (e.g. Dutch Hunger Winter)
* Sleeper effects
prenatal development
- follows the cephalocaudal direction
- goes from simple to complex
**cephalocaudal direction **
develops from head to feet
Three Primary Stages of
Prenatal Development
-
Germinal Period: The Zygote
– fertilization to implantation -
Embryonic Period: The Embryo
– 12 days - 7/8 weeks -
Fetal Period:The Fetus
– 9 weeks - 40 weeks
prenatal development
starts at conception to birth
Fertilization
- Millions of sperm
- Most perish along the way
- Several hundred at the site of the egg
- With penetration, egg involved
– Egg creates barriers to additional sperm
– Pulls sperm into center, creates filaments to allow nucleii to join
the result of the sperm and egg joining is called a zygot
In vitro fertilization
an egg is extracted from a womens ulterus and a sperm is extracted and put together ‘‘artificially’’ and then implitation
1.Germinal Period : The Zygote #
within the first month of pregancy
Duration: 1-2 weeks
- Rapid cell division(zygot) > Extreme vulnerability
- By 4 days a ball of cells
- Creation of inner & outer masses of cells (blastocyst)
- 10-12 days: Implantation in the uterus wall
- 4-5 days:Differentiation of cells (before, all cells equipotential, embryonic stem cells)
- Outer layer will become Placenta, Amnion, & Umbilicus
- Inner cell mass will becomes the fetus
2. Embryonic Period
duration: 2-8weeks
- Placenta continues developing
- AT IMPLANTATION
- Embryo differentiates into:
– Ectoderm > skin, sense organs, PNS & CNS
– Mesoderm > muscles, circulatory system, skeletal, reproductive & excretory systems
– Endoderm >digestive system, lungs, urinary tract & glands - Heart & Neural Tube begin to form( not functioning)
- Remember – each cell has identical DNA
2. Embryonic Period
- By 7 weeks
– respond to external stimuli
– sexual differentiation begins (but reproductive system differentiation a few weeks later) - All major organ systems have begun to form and are in place
- By the end of this period, spontaneous movement occurs
- At 8 weeks, 3 cm long, 1 gram(tiny)
3.Fetal Period
- Begins around9 weeks
- Development and growth
- Skin and hair develop
- First movement felt at about 16 weeks
- Organization and establishment of :
– states of arousal by 4th month
– sleep/wake cycles by 28-30 weeks
– sensory systems
– learning
Prenatal experience effects
(nature and nurture; sensitive periods)
- Own movement impacts development
– *Experience Expectant; e.g. swallowing; breathing
– Hand movement involves bringing hand to mouth - Some continuity to after birth
– Fetuses with < heartbeat, later inhibited
– Hand thumb is sucked on, dominant hand
Prenatal experience effects#
(nature and nurture; sensitive periods)
- Positive: Diet, exercise, emotional well being
-
Teratogens: Harmful environmental agents (time of exposure is also important)
– Dose-Response relations
– Individual differences in genetic susceptibility -
the embryoric period is the most vulnerable
– Rapid differentiation
– Placenta not yet fully formed
Sensitive Periods
a period where the fetus are more sustable to harm from outside and inside influences
usually early into the pregnancy like first and second trimester - embryoric period
Teratogens
-
Thalidomide: Sedative for
morning sickness, given in the 1960’s
– Caused severe limb deformation if taken at
– weeks 4-6 - Drugs: Cocaine, opiods, marijuana, even aspirin,drinking
-
Smoking:
– Low birth weight, impaired breathing during sleep, miscarriage, later cancer, increased aggression
– Low birth weight transfers to the next generation - Best to avoid all drugs if chance of conceiving
- However, drugs may be necessary
– Antibiotics
– Antidepressants
alcohool as a teratogen
Fetal Alcohol Spectrum Disorders (FASD)
includes Fetal Alcohol Syndrome
(FAS) :infants generally born smaller and abnormalities,attetion problems
Alcohol Related Neurodevelopmental Disorder (ARND)
Other teratogens?
- Disease – CMV, Measles, zika varius
- Smoking
- Drugs – antibiotics
- Recreational drugs
- Acne medication
– Acutane can cause birth defects - stress
- depression
Development of Sensory Systems
- inculde Schneirla, Turkewitz & Kenny
- Sequential development of the sensory systems:
somesthetic/ vistibular(perception/balance- move smoothly)>chemical >auditory> visual
this theory helped take care of preborns
Perception & Learning in the Womb
-
Auditory
– respond to & discriminate sound in utero - Neonates recognize:
– Mother’s voice
– Native language
– Songs and stories heard prenatally
-can discriminate human vc animal sounds -
Visual
– Can even see light in utero
– But face preferences may not require! - prefer from top faces rather the from down
-
Taste
– Benoit Schaal:
– Half mothers
ingested anise
during pregnancy infants born feom mothers who had it feel more incline to the smell then mother who didnt consume ingested anise
– Tested neonates - Facial expression
in newborns - Orientation
Perception & Learning in the Womb
teste
-test buds start to develop by 8 weeks postconception and they start sending information about teste by 14 weeks
-this means way before birth the child have experience with taste
-during the prenatal development they swole aminotic fluid which have traces of what the mother has eaten
very similar to smell as is developed withing 9weeks and is influenced by amionic fluid
touch
sensory experience is experienced by 4 - 7 weeks
habituation
when the newborn decresse response to a repeted stimuli
Maternal Depression
With and without SSRI exposure(anti-depression)
Do SRIs and/or Maternal Depression
impact the timing of change?
IV
SRI Exposure
DV
no exposure to SRI
Timing and/or processing
If SRI exposure interferes with processing, SRI exposed fetuses should fail to discriminate vowels
If SRI exposure accelerates onset, SRI exposed fetuses, but not control fetuses, should discriminate consonant distinctions
Method
Speaker ~ 10 cm from
mother’s abdomen
- Sounds at ~95db
- Mother listens to a story
through noise canceling
headphones - Fetal HR recorded
- 30 sec blocks, then change
- Discrimination indicated by
HR deceleration following
stimulus onset - 10 sec windows
- Analyses control for maternal
mood
results
SRI influences Does accelerate onset of consonant discrimination compering to mothers who didnt take SRI
SRI influences Acceleration may or may not be advantageous(we do not know yet)
