PSYB20H3 Lecture Notes - Lecture 3: Cortisol, Blood Proteins, Cardiotocography
PSYB20-Lecture 3: Pregnancy and Prenatal Development
Principles of Growth
-Cephalocaudal principle
oBabies will have big heads, because the head develops first
-Proximodorsal principle:
oDevelopment from the middle, outwards (heart to finger tips)
oCell migration: starting off as a clump of cells that look nothing like humans and
then migrate to where they need to go to continue development
Stem Cells:
-Unspecialized cell and can become any cell
-Can be induced to become certain cells w specialized functions
-Focus on regenerative research
oTake a embryonic stem cell and take it to treat diseases
Cell Death:
-When the cell gets triggered to die
oCan have important role
-For hand development, it is important for cells to die to form fingers otherwise we would
have webbed hands
-Death of cells contributes to
Principles of Growth:
-Gestation: prenatal period of development between conception and birth
o37-41 weeks (40 weeks is normal)
The Germinal Stage:
-First 2 weeks of development
-Fertilization usually occurs in the fallopian tubes
-Dividing through mitosis
-Embryo will implant itself into the uterine lining (1 week after conception)
-Chemical pregnancy: the embryo hasn’t attached itself to the uterine lining
oWoman will get their period as normal and wont even know
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oA test can be taken where it show low levels of pregnancy, but those levels do
not increase, therefore showing that they were pregnant but not anymore
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Stages of Embryonic Development:
-Embryonic disk: a thickened cell mass from which the embryo begins to develop
-Endoderm: lowest layer: these cells become digestive system, pancreas, respiratory
system, etc.
-Ectoderm: upper layer: becomes the outer layer of skin, nails, hair, brain and spinal
cord, etc.
-Mesoderm: middle layer: muscles, skeleton, excretory and circulatory system (last to
develop)
-Each one of these layers is predetermined to become something in a full human being
Brain Development:
-4th week of gestation, the neural tube begins to close and develops into the nervous
system
-Starts to close, one part will become the brain and the other becomes the spinal cord
-Neurogenesis occurs a lot
-Hearts, eyes, etc. form after conception
The Embryonic Stage:
-Amniotic sac: encases the developing embryo
oHelps protect the developing baby
oHelps the fetus move more freely through the uterus
-Placenta: attached to the uterus, oxygen, nourishment, and waste to pass between
other and embryo
-Embryo is attached to the placenta through the umbilical cord
-Spontaneous abortion: abortion
oMale fetuses are more likely to be aborted and this happens usually in the first
trimester
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The Fetal Stage:
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-Appearance of the first bone cells at 8 weeks
-Will grow rapidly and grow 20 times it previous length
-230, 000 immature neurons that are produced every minute
-25thweek and first few months after birth
-Brain is partially formed by 20 weeks of gestation
-12th week:
oFetus can swallow and inhale amniotic fluid
-26th
oRespond to sound and vibration
oRise and level off at 32 weeks of gestation
-Males tend to move more than females
-The mother cannot feel it at the 5-6 weeks at that time (jerks at that time, the baby is
learning how to use their limbs)
-The swallowing is there to help prepare the digestive track that will come after birth
-Breathing will help the diaphragm and muscles develop for after birth
oWill take in some amniotic fluid but isn’t drowning because the fetus is receiving
oxygen from the umbilical cord
-Tactile stimulation: can feel itself hitting other things, can hit itself by mistake, can suck
their own thumb
-Taste: can taste what is coming in through the amniotic fluid and whatever the mother is
eating a lot their baby will eat it as well
oSomething they tasted when they were in the uterus can comfort them in their
future adult lives
-Smell: the baby can smell what the other is smelling
-Sounds: can heard muffled sounds of what is happening in the environment
-DeCasper and Spence:
oHad the mother expose the infant to certain sounds when in the uterus
oIf the baby started sucking more when exposed to those same sounds, it
remembers it from when it was in the uterus
-Kisilevsky et al:
oFetal heart rate detection, infants like their mother’s voice over other women’s
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Document Summary
Cephalocaudal principle: babies will have big heads, because the head develops first. Proximodorsal principle: development from the middle, outwards (heart to finger tips, cell migration: starting off as a clump of cells that look nothing like humans and then migrate to where they need to go to continue development. Unspecialized cell and can become any cell. Can be induced to become certain cells w specialized functions. Focus on regenerative research: take a embryonic stem cell and take it to treat diseases. When the cell gets triggered to die: can have important role. For hand development, it is important for cells to die to form fingers otherwise we would have webbed hands. Gestation: prenatal period of development between conception and birth: 37-41 weeks (40 weeks is normal) Embryo will implant itself into the uterine lining (1 week after conception) Chemical pregnancy: the embryo hasn"t attached itself to the uterine lining: woman will get their period as normal and wont even know.
