The heart, the blood,
and the blood vessels make up a system for the transport of gases,
nutrients, and chemical wastes. The primary functions of the circulatory
system are the following:
- To transport nutrients and oxygen to the cells.
- To remove waste and carbon dioxide from the cells.
- To provide for efficient gas exchange.
Blood vessels allow oxygenated blood and nutrients
to reach the tissues and wastes to be removed from the tissues.
The blood is the medium that carries oxygen and
nutrients to the tissue and is also the medium by which waste is transported to the appropriate locations.
The heart is made up of cardiac muscle and is
divided into 4 different chambers. The top two compartments are
called atria, while the bottom two compartments are called
Interior anatomy of the
Exterior view of the
There are three
basic types of blood vessels:
these carry "oxygen rich" blood away from the heart,
except in the case of the artery to the lungs.
these are the sites of gas exchange between the tissues.
3. Veins- these
return "oxygen poor" blood to the heart, except for the
vein that carries blood from the lungs.
On the right is a diagram showing
how the three connect. Notice the artery and vein are much larger
than the capillaries. This junction is called a capillary
Why do you think this is?
Why are the capillaries shown with
two different colors?
Why is the vein shown as blue?
to watch an animation of the heart beating
The circulatory path
|Note: Arterial blood (oxygen rich
in red , and venous blood (contains less oxygen) is in blue.
Now, can you draw the parts of the circulatory system
and show which parts contain oxygen-rich blood and which parts contain
oxygen poor blood?