Download The Heart

The Heart
Circulatory System
Try it!
Stand up and put one hand in the air and one hand
below your waist - stand like that for one minute!
Do you notice difference In your palms; why does it
look the way it does?
Is there a difference between your right and left
hand when either is below your waist?
Based on this experiment, can you explain how
blood gets to our brains?
What happens if there isn‛t any blood going to our
brains?
Misunderstood Geniuses:
William Harvey
https://www.youtube.com/watch?v=7NOU4McjtXs
*Disclaimer: Some inappropriate
language!
Your body is made of trillions of cells.
• Each cell needs oxygen
and nutrients.
• As your cells carry out
their functions, they need
to get rid of wastes like
carbon dioxide.
• To do this, your body has
a transportation system.
Circulatory System
• The system that
transports blood
through the
body, delivers
essential
substances to
cells, and
removes wastes.
Circulatory System
The circulatory
system consists of:
• Heart
• Blood Vessels
• Blood
What pumps over two million liters of blood per year
and weighs only 300 grams?
THE HEART!
In fact …
• Your heart pumps around 5 Liters
of blood at the rate of about 60
beats per minute.
• That’s about 100,000 beats per
day and 35 million beats in a
year.
The heart is a hollow organ found in
the middle of your chest.
The Heart
• The heart contracts (squeezes) to
pump blood throughout the body.
• It is made mostly of cardiac muscle
tissue.
• Contractions happen when this
muscle tissue shortens.
The right and left sides of the heart have
separate functions.
Right Side
The right side of the heart collects
oxygen-poor blood from the body
and pumps it to the lungs where it
picks up oxygen and releases
carbon dioxide.
Body ----------------------> Lungs
This is called:
PULMONARY CIRCULATION
Left Side
The left side of the heart then
collects oxygen-rich blood from the
lungs and pumps it to the body so
that every cell in the body has the
oxygen it needs.
Lungs ----------------------> Body
This is called:
SYSTEMIC CIRCULATION
The heart has four chambers.
Chambers of the Heart
• Each chamber has a one-way valve at
its exit. A valve is a flap of tissue that
prevents the back-flow of blood.
• When each chamber contracts, the
valve at its exit opens.
• When each chamber relaxes, the valve
closes so that blood does not flow
backwards.
The heart contracts (or beats) in TWO stages.
In the first stage, blood enters the
atria (plural of atrium).
• The left atrium receives oxygen-rich
blood from the lungs.
• The right atrium receives oxygenpoor blood from the body.
When the atria contract, blood is
squeezed into the ventricles.
• In the second stage, while the atria
relax, the ventricles contract
together. This pushes blood out of
the heart.
• Blood from the right ventricle goes
to the lungs.
• Blood from the left ventricle goes
to the body.
Ventricle Walls
The left ventricle wall is
much thicker and
more muscular than
the right ventricle wall.
This is because the right
ventricle is responsible
for pumping blood to
the entire body, which
requires a lot of force!
Stages of Heart Beat
• Then the heart muscle
relaxes before the next
heartbeat.
• This allows blood to flow
into the atria again.
Useful Videos!
• How Your Heart Works (Kids Health)
https://www.youtube.com/watch?v=_e
VG45_iF9U
• Exploring the Heart – The Circulatory
System
https://www.youtube.com/watch?v=s5iCoCaofc
Useful Videos!
• How the Heart Works 3D Video
https://www.youtube.com/watch?v=oHM
mtqKgs50
• The Heart and Circulatory System (Mayo
Clinic)
https://www.youtube.com/watch?v=CWFy
xn0qDEU
• The Heart Part 1 (Crash Course)
https://www.youtube.com/watch?v=X9ZZ6
tcxArI