Transcript Creating Life

Science - Unit 6
Creating Life
Language Learning Goal
Define:
• Reproduce
• Egg
• Sperm
• Fertilize
• Fetus
• Uterus
Content Learning Goal
• Students will learn how humans reproduce
(or make more of themselves). We will
learn what organ system is in charge of
reproducing and how it works.
Creating Life
• Life begins with one cell.
• From that one cell, billions of cells are
made to form a human body.
• Humans have organ systems that make
them able to make new humans…babies.
• If we didn’t have these organ systems, the
human race would die out.
Starting from One Cell
• The human body has an organ system to
reproduce humans. It is called the
Reproductive System.
• Babies are born with all the parts they
need for their reproductive systems, but
the system doesn’t start working until
around Age 12.
Puberty
• Around the time kids turn 12 (may be
younger or older), another organ system
starts sending hormones to the
reproductive system. Do you remember
what system sends hormones?
• Right! The Endocrine System.
• The hormones tell the reproductive system
to start producing sex cells.
• This age in a child’s life is called “puberty”.
Sex Cells
• In the female, sex cells are called eggs.
• In the male, sex cells are called sperm.
• These two kinds of sex cells cannot make
new life on their own, they must join together
and become one cell. When that happens,
we say the sperm fertilizes the egg.
One Cell Continued
• The sperm and egg combine to make one
cell. That one cell divides and becomes
two cells. Those cells divide and make
four cells and so on.
• As the cells divide, they form tissues,
organs and different body parts. Slowly,
the cells build up to make a baby. This
forming baby is called a fetus.
Reproductive Organs
Male:
• Testicles make sperm cells. (Men have
two testicles). The sperm travel from the
testicles through tubes to leave the body.
The final portion of the sperm’s journey in
a male body goes through the urethra in
the penis. (Note: When a male urinates,
urine passes through this same tube.)
Reproductive Organs
Female:
• The ovary produces egg cells. (Women have
two ovaries – one on each side).
• The egg cells move through fallopian tubes. If
the egg cell joins a sperm cell along the way, it
becomes fertilized. It then attaches itself to the
wall of the uterus where it will grow and
develop into a fetus. (Note: if the egg does not
meet a sperm, it is simply absorbed back into
the body…this happens very often. Women
make eggs every month.)
Reproductive Organs
Female:
• The fetus lives in the uterus. When the
fetus is fully developed, it is a baby ready
to be born. It leaves the uterus through
the vagina in an amazing and painful
process.
• How long do you think it takes a fetus to
develop and be ready to be born?
Nine Months
• It takes 40 weeks (or just over 9 months)
for a baby to develop
• Life starts at one cell. The cell multiplies
and attaches itself to the wall of the uterus.
At that stage, it is called an embryo. It
does not yet look like a human baby, but it
is alive (its heart is formed and beating.)
• Look at the diagram on Page 136 to see
how an embryo turns into a fetus.
3 Months
• In Picture B, the forming baby is 3 months old. It is
now starting to look like a human baby. At this
stage, it is no longer called an embryo…it is now a
fetus.
• It has nerves, lungs, stomach, intestines, bladder
and muscles. The muscles are working and allow
the baby to move in the uterus.
• The baby is still connected to the wall of the uterus,
but now it is through a tube to the placenta.
Everything a baby needs to grow, it gets from its
mother through the placenta.
6 Months
• Picture C shows a growing fetus at six
months old. Its respiratory, circulatory and
digestive systems are almost complete. It
moves around a lot (kicks, turns and
swings its arms) and the mother can feel
the baby move.
• Babies born at 6 months could survive, but
they are not ready yet for the outside world
and will have trouble breathing and eating.
9 Months
• Picture D shows a baby that has grown inside
its mother for nine months. Do you think it is
ready to be born?
• If it were born now, do you think it would
survive? How big do you think it would be?
Review
• Work on the Review Questions #1-6 on
Page 137.
Going Deeper…
• Earlier we talked about the “placenta”.
The placenta is what gives a baby all the
good things it needs to grow and passes
the waste back to the mother to get rid of.
• The placenta gives the baby everything it
needs, and the placenta gets everything
from the mother. This means that
everything the mother has in her body is
being passed to her baby through the
placenta.
What does that mean?
• That means that a pregnant mother wants
to take lots of good things into her body to
share with her unborn baby. She also
wants to avoid lots of bad things so she
doesn’t harm her baby.
Pregnant Mom
Examples: Would a pregnant mom want to do
these things? What do you think? Why?
• Eat healthy meals
• Drink Alcohol
• Take vitamins
• Smoke
• Drink lots of water
• Do drugs
Parents
• Let’s talk about what you think it takes to be
a good new parent. What do new parents
have to do? How are their lives different
because they have a new baby?