Aging changes in the lungs    • Respiratory cilia   • Changes in
lung tissue with age   The lungs have two main functions. One
is to get oxygen from the air into the body. The other is to
remove carbon dioxide from the body. Oxygen is needed by the
body to work properly. Carbon dioxide is a waste gas the body
produces when it uses oxygen.  Unsupported extension  During
breathing, air enters and exits the lungs. When you breathe in
(inhale), air flows through the airways into the lungs. The
airways are made of stretchy tissue. Bands of muscle and other
support tissue wrap each airway to help keep them open.  Air
keeps flowing into the lungs until it fills tiny air sacs called
alveoli. Blood circulates around these air sacs through tiny
blood vessels. Oxygen crosses into the bloodstream at the place
where the blood vessels and air sacs meet. This is also where
carbon dioxide crosses from the bloodstream into the lungs to be
breathed out (exhaled).   Unsupported extension    Aging Changes
and Their Effects on th