The Human Heart:
The Most Important Muscle in the Human Body
(1) As you have already learned, there are muscles all over your body. All
of them are important, but not all of them are vital. The muscle you cannot
do without is inside your chest. It is the heart!
(2) The heart is responsible for two things. First, through the blood it
pumps, the heart provides oxygen and nutrients to our cells to keep us
alive. Second, and again through the blood, it carries away wastes from
these active cells to special organs that rid them from our bodies.
(3) The heart is really a pump, or two pumps in one. The right side receives
blood from the body and pumps it to the lungs. The left side does the
opposite: it receives blood from the lungs and pumps it around the body.
The Beat Goes On!
(4) The heart is a involuntary muscle. This means it works on its own
without us having to think about any of its average one hundred thousands
beats daily. With each beat, your heart fills with blood. Then it contracts to
pump the blood through your body. This is done all day, all night, all the
time.
Heart Parts
(5) The heart has four different
hallow areas called chambers. There
are two chambers on each side of the
heart. Each one is separated by a
valve, a flap of tissue that opens and
closes to keep the blood flowing in
the right direction.
© Prepared by Jim Cornish, Gander, Newfoundland, 2003.
(6) The two chambers on top are called the atria (ay-tree-ah). The atria are
the chambers that fill with blood. The two chambers on the bottom are
called the ventricles (ven-trick-ulz). They pump the blood out of the heart,
first to the lungs and later to the rest of the body. Separating the two sets of
chambers is a thick wall of muscle called the septum (say: sep-tum). The
septum's job is to separate the left side and the right side of the heart.
(7) The atria, ventricles and valves work together to pump blood. The atria
fill with blood, then pump it into the ventricles. The ventricles pump blood
out of the heart.
Recycling
(8) The blood in our bodies is used over and over again. Its movement
through the heart and around the body is called circulation and can be
viewed as a cycle.
(9) Beginning at the left side of your heart, fresh, clean oxygen-rich blood
is pumped around our bodies. The cells through-out our bodies removes the
oxygen from the blood and use it, like fuel, to work and grow. In these
processes, the cells creates carbon dioxide and other wastes
that must be removed to keep the cells healthy. The blood is
responsible for picking up this waste, delivering it to the
kidneys where, except for the carbon dioxide, it is
removed from the blood.
(10) The blood with its load of carbon dioxide returns
to the right side of the heart where it is then pumped
to the lungs to get rid of the carbon dioxide and to
pick-up fresh oxygen. The oxygen-rich blood goes
back to the left side of the heart and is then
pumped around the body to complete the cycle.
Amazingly, it all happens in less than half a minute!
© Prepared by Jim Cornish, Gander, Newfoundland, 2003.
Networks
(11) The heart uses a network
of tubes to get blood throughout
the body. These tubes are called
blood vessels. The blood
vessels that carry blood away
from the heart (the fresh blood
that's full of oxygen) are called
arteries, and the ones that carry
blood back to the heart (the
stale blood that's carrying the
waste) are called veins.
Listen to the Lub-dub
Amazing Facts
About the Human Heart
Æ
It is about the size of a fist.
Æ
It beats on average 70 times per
minute. That’s 4200 per hour,
approximately one hundred thousand
beats per day, 365 million beats per
year and about 30 billion beats in an
average life time of 80 years.
Æ
An adult heart pumps 7,500 litres of
blood daily.
Æ
It takes 20 seconds to pump blood to
every cell in your body.
Æ
Blood is cleaned by the kidneys.
Æ
If you lined up all the blood vessels in
your body end to end, they would
wrap around the earth twice!
(12) When you go for a
checkup, your doctor uses a
stethoscope to listen carefully to your heart beat. A healthy heart makes a
"lub-dub" sound with each beat. This sound comes from the valves
shutting inside the heart. The first sound (the "lub") happens when the
blood hits valves between the atria and ventricles. The next sound (the
"dub") happens when the blood hits the aortic and pulmonic valves that
close up as the heart relaxes to fill with blood for the next beat.
Where’s My Pulse?
(13) You can feel your heart beating in several different areas of the body.
The most common place used is the wrist just below your thumb. You'll
know that you've found your pulse when you can feel a small beat under
your skin. Each beat is caused by the contraction of your heart. If you want
to find out what your heart rate is, use a watch with a second hand and
count how many beats you feel in one minute.
© Prepared by Jim Cornish, Gander, Newfoundland, 2003.
Keep Your Heart In Shape
(14) Most children are born with a healthy heart and it's important to keep
yours in good shape. Here are some things that you can do to help keep
your heart strong and healthy.
(15) Remember that your heart is a muscle. Just like you need to exercise
your leg and arm muscles, you need to exercise your heart, too. Regular
exercise is a great way to keep your heart in shape. At least 15 to 20
minutes of exercise each day will give your heart the workout it needs to be
the strongest muscle it can be.
(16) Eating a variety of healthy foods is great for your heart. Avoiding a lot
of fatty foods will keep your heart happy, too.
(17) Stay away from smoking! Smoking is bad for every part of your body,
and especially your heart. Your heart and blood vessels hate cigarettes,
because smoking makes their jobs much harder.
© Prepared by Jim Cornish, Gander, Newfoundland, 2003.
The Human Heart Worksheet
Comprehension
1.
What are the responsibilities of the heart?
2.
What does the left side and the right side of the heart do?
3.
What is the source of the sound in your heart beat?
4.
What can you do to keep your heart healthy?
5.
What happens to the blood in the lungs?
Vital Statistics About the heart
a.
Average number of beats for an adult heart . . . . . . . . . . . . . . . . ____________
b.
Number of litres of blood heart pumps daily . . . . . . . . . . . . . . . . ____________
c.
Number of chambers in the heart . . . . . . . . . . . . . . . . . . . . . . . . ____________
d.
Length of time to pump blood to every cell in the body . . . . . . . . ____________
e.
Amount of blood that goes through kidneys for cleaning
f.
Number of minutes of exercise required daily to keep heart healthy____________
. . . . . . ____________
Number the steps in the heart’s process of pumping blood correctly.
_____ When this blood reaches the cells, it provides them with oxygen and picks up
carbon dioxide and other wastes.
_____ The blood is then pumped to the body, stopping by the kidneys for the removal of
the other wastes along the way.
_____ It is then pumped from the heart to the lungs where it gives up the carbon dioxide
and picks up oxygen.
_____ The oxygen rich blood then returns to the heart right atrium.
_____ First, blood is pumped around the body from the left ventricle.
_____ The blood, now full of waste returns to the heart left atrium.
© Prepared by Jim Cornish, Gander, Newfoundland, 2003.
Backbone Puzzle on the Human Heart
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v
n
Instrument used to listen to the heart.
Considered the most important muscle in the body.
20-30 minutes of this each day will help keep your heart healthy.
A waste gas given off by body cells.
The heart chambers that receive blood.
Name given to the squeezing action of the heart.
The heart is this type of muscle.
The four hallow sections of the heart.
Tubes that carry blood around the body.
The movement of blood around the body.
The wall that separates the left and right sides of the heart.
The heart beat felt in the wrist.
These four “doors” control direction of blood flow through the heart.
Chambers the pump bllod away from the heart.
The system that includes the heart and lungs is also called the ___________________
system.
© Prepared by Jim Cornish, Gander, Newfoundland, 2003.
Diagram of the human heart.
G
Add the following labels. Some labels may be used more than once.
pulmonary artery
left ventricle
pulmonary vein
septum
valve aorta
right ventricleleft atrium
right atrium
G
Colour the vessels that bring blood to the body red.
G
Colour the vessels that bring blood to the heart blue.
© Prepared by Jim Cornish, Gander, Newfoundland, 2003.