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Unit 19: Biology Part 2 Page 57 of 137
something we think about Diaphragm
regularly, it is absolutely required
for the survival of the cells in your One important muscle not shown in
body. the picture above is the
diaphragm. This sheet of muscle
As you breathe, oxygen flows into goes along the bottom of the rib
the body and carbon dioxide flows cage. The diaphragm contracts to
out. This very important exchange make more space in the chest,
of gases is the main function of allowing air containing oxygen and
your body’s respiratory system. other gases to come in. It then
relaxes, causing there to be less
The Parts of the space in the chest and forcing air
Respiratory System containing carbon dioxide and
other gases out.
The respiratory system, like all
body systems, is a group of
organs and tissues all working
together for a common purpose, in
this case exchanging oxygen for
carbon dioxide. Some of the
respiratory system’s parts are
shown below.
Figure 37 – The diaphragm
goes across the bottom of the
rib cage.
Nose and Nasal Cavity
The first stop for air entering your
body is your nose. In the nose,
Figure 36 – The parts of the the air is warmed and moistened.
respiratory system work The air also acts as a filter. Hair
together to provide oxygen and and mucus in the nose catch
get rid of carbon dioxide. particles in the air that could be
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