The Heart and
Circulatory System
Copyright 2010.
What are some of the things
that a heart symbolizes?
What is the real purpose of the heart?
Functions of the Circulatory
A cell needs oxygen
and nutrients.
• Deliver nutrients and
oxygen to body cells.
• Carry carbon dioxide
and other waste
products away from
the body cells.
A cell needs to get
rid of carbon dioxide
and other wastes.
Organs of the Circulatory
• Heart: A muscle that pumps
blood to all parts of the
– The human heart is
made of four chambers.
The right atrium, right
ventricle, left atrium and
left ventricle.
– Valves are flaps of tissue
that open & close to let
blood in & out of the
parts of the heart.
Fun Fact!
•Your heart beats with
about the same strength it
takes to squeeze a tennis
•Squeeze a tennis ball and
see how hard that is.
• Now think what it must
be like for your heart to
do this 70 times a minute,
60 minutes an hour, 24
hours a day - for a
Do all animals’ hearts
have 4 chambers?
Look at the four chambers of the
Question: Why is the right labeled left and the left labeled right?
Answer: Anatomy drawings are labeled as if they were in a person or
animal that is facing you!
This is a sheep’s heart that has been dissected, or
opened. Locate the four chambers of the heart. The
stringy structures in the heart are the valves that open
and close to let blood move between the chambers of
the heart.
Stop and Think:
• What are some things that could
make your heart beat faster?
• What are some things that could
make your heart beat slower?
Blood Vessels
• Arteries are pipelines that
generally carry blood away
from the heart. They carry
oxygen-rich blood. They
are usually designated by
the color red because
oxygen-rich blood is red.
• Veins generally carry
oxygen-poor blood back to
the heart from the rest of the
body. They are usually
designated by the color blue
because oxygen-poor blood
is a darker color.
Your arteries
and veins run to
every location in
your body in a
Why do you think some people compare our circulatory
system to a network of roads?
Blood Vessels
• Capillaries are
microscopic blood
vessels that connect
arteries to veins.
The Capillaries are in between the artery
on the left and the vein on the right
They are where oxygen
& waste exchange occur.
• They are only big enough
for one blood cell to pass
at a time.
Click here for a video of blood flowing
in the blood vessels
The little donut-shaped red blood cell (scientific
name erythrocyte) squeezes through the
capillary and drops off its cargo of nutrients and
• This is the path of the blood through the heart,
lungs, and body.
Click here for a silly
circulation song!
Follow the arrows in the pictures
to trace the flow of blood through
the heart, lungs and body.
Now discuss these review
• What are the functions of the circulatory
• What are the major organs of the circulatory
• What are the main parts of the heart?
• What do arteries and veins do?
• How big are capillaries?
• What path does blood take as it goes
through your body?
• A thinking question: Do you think all living
things have a heart?