How lungs work
These organs exhange carbon dioxide for oxygen. When
oxygen-rich air is inhaled, the muscles between the ribs
contract and expand the chest; air inflates the lungs.
When air is exhaled, the lungs get rid of carbon
dioxide produced by cells. The muscles between
the ribs relax and the chest cavity gets
smaller. The cycle repeats with each breath.
Bronchi
Air
Air enters the brochi and
then passes to each
lung. It then travels
to the alveoli.
Alveoli
These tiny air sacs
contain a high
concentration of
oxygen. The alveoli
exchange oxygen with
carbon dioxide in the
body, and they help
oxygen-rich blood to
reach the heart.
Breathing helps to
keep the oxygen levels
high in the alveoli.
Smoking coats the
alveoli and prevents
the exchange of gases.
HEART
NORMAL
Alveoli tissue
Normal
alveoli tissue
provides easy
exchange of
gases.
clusters
EMPHYSEMA
Alveoli tissue
The walls between the
air sacs lose their
ability to stretch and
recoil. Elasticity of lung
tissue is lost. This
prevents the exchange
of oxygen and carbon
Damage is irreversible dioxide. Breathing is
and causes holes in
difficult and results in
the tissue.
shortness of breath.
SOURCES: American Lung Association, http.www://howstuffworks.com
Air is
the sacs.
Alveoli
clusters