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Circulatory System
What Do These Two Systems Have In Common?
(Think-Pair-Share)

Subway System

Circulatory System
Job of the Circulatory System

Acts as a highway to carry oxygen
and nutrients toward your cells while
carrying wastes and carbon dioxide
away from cells.

Your heart pumps 4300 gallons of
blood per day!

THINK! - What parts make up your
circulatory system?
 Heart
 Blood vessels (arteries, veins,
capillaries)
 Blood
The Heart

Your heart is located behind the sternum and is the size of your fist.

THINK! – What muscle tissue makes up the heart?



Cardiac
The heart has 4 chambers:

The two upper chambers are the atria.

Two lower chambers are the ventricles.

The septum is a thick muscle that separates the right and left sides of the
heart so oxygen poor and oxygen rich blood do not mix.

Valves are flaps of tissue that prevent the blood from flowing backwards
Your Heart as 2 Pumps - http://www.kscience.co.uk/animations/heart.swf
Parts of the Heart
Aorta
(carries blood to body)
Pulmonary Artery
Vena Cava
(brings blood from body
back to the heart)
(carries blood from
the heart to the lungs)
Pulmonary Veins
Left Atrium
Right Atrium
Left Ventricle
Valves
Right Ventricle
Septum
Blood Vessels of the Body

Arteries


Veins


carry blood “away” from the heart
carry blood “back” to the heart
Capillaries

the tiniest vessels where oxygen
and nutrients can diffuse from
bloodstream into cells
 Only 1 cell thick
 You can see them nourishing the
white part of your eye
The Heart and Circulation

The job of the heart is to circulate blood throughout
the body

The Heart is really 2 pumps working side by side:

The right side pumps blood to the lungs to pick up
oxygen.

The left side pumps oxygenated blood to all tissues of
the body.

Check out this simple clip first

http://www.kscience.co.uk/animations/bloo
d_system.swf
Activity: Trace the Pathway of Blood During a Heart Beat
1. Oxygen poor blood enters the
heart through the vena cava.
2. Blood is then pumped into the
right atrium and then right ventricle.
3. Oxygen poor blood is pumped,
exits the pulmonary artery and
goes to the lungs.
4. Once it has oxygen, blood
reenters the heart.
5. Blood is pumped into the left
atrium and then left ventricle.
6. Oxygen rich blood is pumped
out of the aorta to the body tissues.
Label and Color Code the Pathway of Blood
THINK! – What sound does the
heart make?
LUB DUB
LUB DUB
 As blood is pumped from
atria to ventricles the “lub”
sound is made
 As blood is pumped from
ventricles to body, the “dub”
sound is made.
Heart Disease

Atherosclerosis

Build up of fat and cholesterol in
arteries
 Leads to heart attack
 Heart Disease: United Streaming

Hypertension


High blood pressure
Clogged arteries can cause high
blood pressure
 Normal pressure is 120/80

THINK! – What do these
numbers mean?


First number – measures
pressure when ventricles
contract
Second number – measures
pressure when ventricles relax