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Child Development
Chapter 5: Prenatal Development
Section 5-1
The Developing Baby
Pipe Cleaners
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With your pipe cleaner, make something to
represent your feelings about learning
about sexuality and conception in class.
Bell Work
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Read p. 141
Answer these questions on your own
paper:
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Why would hearing the baby’s heartbeat be
significant for both parents?
What other experience of the baby would be
exciting to them?
Why might hearing the heartbeat be especially
moving for the father?
Objectives
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Distinguish among the three stages of
pregnancy
Describe the prenatal development during
each stage of pregnancy
Explain what changes affect a woman
during each stage of pregnancy
Conception
TPS
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Why is it important to understand how
conception takes place?
Period of the Zygote
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Lasts about 2 weeks
Zygote- fertilized egg
Zygote travel down fallopian tube
Attaches itself to the lining of the uterus
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Lining provides nourishment
At the end of this period the zygote is only
the size of a pin head
Period of the Embryo
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3rd-8th weeks of pregnancy
Embryo: the developing baby
Grows rapidly
The mass of cells develop into all the major
systems of the human body
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Brain begins to take control of these systems
Amniotic Fluid forms
Placenta develops
Umbilical Cord forms
Bell Work
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p. 144- Health Tip
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Answer questions on own paper to turn in
Period of the Fetus
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8th week until birth- about 40 weeks
4th-5th month mother begins to feel baby movesensations are called “quickening”
Fluid grows as fetus grows until just before birth
when fluid begins decreasing
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Baby is swallowing it
7th month- baby capable of living outside womb
but only with great medical help
8th and 9th month- organs become ready to
survive on their own
Fetus can- suck its thumb, cough, sneez, yawn,
hiccup, and even cry
Preparing for Birth
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Baby’s weight begins to shift down in 9th
month- “lightening”
Fetus is turned upside down in mother’s
pelvis
Less active
Muscles of the uterus and abdomen can be
stretched up to 60 times their original size!
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Return to original size in about 6 weeks after
pregnancy.
Section 5-2
A closer Look at Conception
Genetic Package
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Each person inherits characteristics from parents
Chromosomes: tiny threadlike particles in the
nucleus of every cell
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Human babies receive 46 at conception- 23 pairs
Each chromosomes has thousands of genes: the units
that determine inherited characteristics
For every inherited characteristic a person receives two
copies of a gene- mother and father
Dominant Gene: stronger
Recessive Gene: weaker
Making a Unique Person
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Family often times look alike because of
the gene combinations
Sex of a child is also determined at
conception
Two types of sex chromosome: X and Y
Egg cells contain X
Sperm cells contain wither X or Y
Multiple Births
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Identical Twins: Fertilized egg divides into
two separate babies
Fraternal Twins: two eggs are released at
the same time and both are fertilized
2.5% of births are multiple births
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More than 2 babies is even more rare
Most of the time multiple births (more than 2)
results from treatment of infertility: the inability to
become pregnant
Infertility
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Not all people are able to become pregnant
1st step: Doctor evaluates both parent’s
help to determine cause
Fertility drugs may be prescribed if the
cause is eggs are not released every
month
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Several drawbacks: serious side effects, multiple
births, etc
Options for Infertility
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After treatment for infertility some people are still
not able to conceive
Some options:
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Adoption
Artificial Insemination: sperm injected into woman’s uterus
In vitro Fertilization: Egg is fertilized outside body and
then placed in the woman’s uterus
Ovum Transfer: egg from female donor then fertilized
Surrogate Mother