2. FUNCTIONS
Oxygen uptake and exchange
 From the atmosphere to the blood (inside the lungs)
Carbon Dioxide removal
Allows us to speak (air passing across the vocal chords)
Expels heat and water vapor (breathed out)

5. RESPIRATORY SYSTEM (AIR
PASSAGES)
Major parts of the
conducting system:
Nasal cavity (nose):
warms and filters air.
Pharynx (throat): Allows
food and air to pass.
The air is channeled
into the larynx.
Larynx (the voice box):
Air passes through
the larynx on its way
to the trachea. Inside
the larynx are the
vocal cords which
creates the ‘voice’.

6. RESPIRATORY SYSTEM
(AIR PASSAGES)
Trachea (wind pipe): The
airway through which the
air passes on its way to
the bronchi.
Bronchi: Are divided into 2
smaller bronchioles, then
divided into even smaller
bronchioles and so on
until the terminal
bronchioles are reached.
Terminal Bronchioles: The
terminal bronchioles
branch yet again to form
respiratory bronchioles
which also branch to form
alveoli or air sacs.

7. ALVEOLI
Alveoli (air sacs):
are tiny air sacs at
the end of the
respiratory
bronchioles.
Millions of alveoli
are surrounded by
capillaries. This is
where oxygen is
exchanged for
carbon dioxide in
the blood.

8. WHERE DOES THE AIR (OXYGEN) GO?

9. Diaphragm contracts
Ribcage enlarges
Chest cavity volume
increases
Intercostals (muscles)
between ribs help
keep chest open
The enlargement of
the chest cavity
decreases pressure
in the lungs
The reduction in
pressure inside the
chest causes a
sucking effect – air
flows into the lungs
The normal amount of
air breathed in per
breath is about
500ml. This can
increase by 4-5
times when
exercising.
MECHANICS OF BREATHING - INSPIRATION

10. Expiration occurs
when the
diaphragm and
intercostal
muscles relax
This again creates
enough
pressure
(squeeze) to
force the air out
of the lungs
Again, during
exercise, this
process will be
faster – and the
abdominals will
also assist with
this process.
MECHANICS OF BREATHING - EXPIRATION