The THORAX is the
upper part of the
body (chest, etc.), the
ABDOMEN is the
lower part (stomach,
etc.) Between these
is a muscle called the
DIAPHRAGM.
The diaphragm is below the lungs.
BREATHING OUT
Intercostal muscles RELAX
Ribs 'move down'.
Diaphragm relaxes;
becomes more of a curve
This causes the opposite
effect to breathing in. The
volume decreases and
the pressure increases,
causing air to be pushed
out
BREATHING IN
Intercostal muscles CONTRACT
Ribs 'move upwards
and outwards'.
Diaphragm contracts; becomes a more
horizontal shape below the lungs.
These cause the lungs to expand, they
have a higher volume and low pressure.
This low pressure is unbalanced with
the higher pressure outside the lungs,
and therefore air is drawn in
Within the lungs is a network of
tubes through which air is able to
pass. Air is firstly warmed,
moistened and filtered as it travels
through the mouth and nasal
passages. It then passes through
the trachea and down one of the
two bronchi and into one of the
lungs.
Gas Exchange
the 'swapping’ of gases
between the alveolar air and
the blood