Transcript Subobjective 1

Fetal Development
Lesson Objective
The student will explain the development of a fetus in the uterus.
Subobjective 1: The student will describe the different fetal development stages.
Subobjective 2: The student will determine how the embryo gets nourishment.
Subobjective 3: The student will explain how the mother and fetus affect each other's health.
Vocabulary Overview
Building Background
Click the buttons to reveal questions.
List the stages of fetal development.
Describe the key events of each trimester
during a pregnancy.
How does the fetus receive nutrients and
oxygen from the mother?
Before T
or F
Statement
The blastocyst implants into the uterus.
The amniotic sac is how the mother and fetus exchange nutrients and oxygen.
The umbilical cord contains arteries only, no veins.
The blood flow of the mother and fetus never mix but do flow past each
other.
Human pregnancies are divided into 3 trimesters.
After
T or F
Frayer Model
Fill in each box with the relevant information for the given vocabulary word.
• Cell that forms from a
female egg being
fertilized from a male
sperm
Zygote
• Human zygote
• Diploid
• Chromosomes of mother
combine with
chromosomes of father
Frayer Model
Fill in each box with the relevant information for the given vocabulary word.
• A hallow ball of cells
formed from the
developing zygote
• The surface cells allow the
blastocyst to implant into
the uterine wall.
• Small enough to fit inside
the eye of Roosevelt on a
dime
Blastocyst
• Human blastocyst
Frayer Model
• A stage of fetal
development when
three cell layers begin
to develop
Embryo
•
Human embryo
• These three
layers include the
ectoderm,
mesoderm, and
the endoderm.
Frayer Model
• The organ that
connects the mother
to the fetus
• Allows for the
exchange of wastes,
nutrients, and oxygen
Placenta
• Human placenta
Frayer Model
Fill in each box with the relevant information for the given vocabulary word.
• Starting to take on appearance
of the species
• A stage of development from 9 weeks until
birth
Fetus
• Human Fetus
Fertilization
Occurs when the sperm enters the egg and their nuclei fuse.
As soon as one sperm enters the outer layer of the
egg, a protective shield keeps any more sperm
from entering.
Click here to discover what happens when the egg is
penetrated.
Once the egg is fertilized,
it travels down the
fallopian tubes to the
uterus.
As it travels, it divides rapidly
and transforms from a zygote to
a blastocyst.
Implantation
The blastocyst implants into the uterine wall.
Pregnancy has now begun.
The blastocyst develops
three cell layers.
Blastocyst
1. Ectoderm
2.
Endoderm
3.
Mesoderm
Once these layers form, the blastocyst is now
referred to as an embryo.
Embryonic Membranes
There are many structures that protect and nourish the growing
fetus.
Placenta:
the
organ that
connects the
mother to the
fetus
1
3
2
Umbilical Cord:
consists of two
arteries and a vein
that transport
oxygen. Other
nutrients and waste
also travel through
the cord.
Amniotic Sac: a sac
filled with amniotic
fluid that cushions
the fetus from
temperature
changes and
sudden shock
Do the mother's blood and the fetus's blood ever mix?
The blood of the mother and fetus never mix to prevent the mother's body from rejecting the fetus and
ending the pregnancy.
Trimesters
Human pregnancy is divided up into 3 trimesters that are about 13
weeks long.
Many hormones are involved in maintaining the pregnancy:
Estrogen
Progesterone
Human Chorionic Gonadotropin
First Trimester
Embryonic stem cells differentiate into their future tissue or organ.
Embryos are more susceptible to genetic errors, chemicals, or anything harmful the
mother may consume.
First Trimester
Click the images below to link to online video animations.
Weeks 1-9
Weeks 10-14
Second Trimester
The fetus continues to develop physically and mentally.
This results in increased movement that the mother can start to feel.
Second Trimester
Click the images below to link to online video animations.
Weeks 15-20
Weeks 21-27
Third Trimester
Fetus has now reached its largest size.
While most of the major organs and tissues are formed, the fetus is now focused on
gaining weight.
Third Trimester
Click the images below to link to online video animations.
Weeks 28-38
Health of the Fetus
The fetus completely depends on the mother for all of its nutrients.
These nutrients include:
Toxic chemicals taken by the mother can interfere with the fetus's development and
lead to disabilities and deformities in the child.
Health of the Mother
Just as the fetus is affected by the mother's intake, the mother is affected by the fetus.
Pull
Pull
Review Questions
A scientist wants to change the DNA of a sexually reproducing organism and
have the new DNA present in every cell of the organism. In order to do this
after fertilization, she would change the DNA in the ______.
zygote.
testes of the father.
placenta.
ovaries of the mother.
Review Questions
Abnormalities present in the cells that line the uterus may prevent the
production of offspring by directly interfering with the __________________.
Review Questions
The drinking of alcoholic beverages by a pregnant woman is harmful to the
development of her fetus. This is most damaging early in a pregnancy
because during this time ____________________.
Review Questions
Gestation for a human embryo ends when___________.
Review Questions
The embryo is protected from shock by a substance called
_______________.
Wrap Up
Explain how nutrients and oxygen are transported between the mother and her fetus.