Equipping People To Make Sense Of What They Are Told
The respiratory system - Powered by breathing muscles the respiratory tract carries
air into and out of the lungs, during inhalation oxygen is absorbed by the body from
the air, during exhalation carbon dioxide waste is expelled from the body into the
air. Vocalisation is a secondary function of the respiratory system.
This respiratory system in close conjunction with the circulatory system is responsible
for supplying all body cells with essential oxygen as well as removing carbon dioxide
from the body.
Inhaled air enters the lungs from the trachea which branch’s at its base into two
main airways (the primary bronchi) Each of which enters its lung at a site known
as the hilium, the area where the main blood vessels pass into and out of the respective
lung.
The ‘primary bronchi’ further divides and becomes ‘secondary bronchi’ which then
divides further into ‘tertiary bronchi’. Numerous divisions occur from this point
which continually decrease in diameter eventually forming the narrowest airways;
The terminal and then the respiratory bronchioles which distribute air to the alveoli.
Alveoli - microscopic air sacs are thin walled structures arranged in clumps at the
end of respiratory bronchioles. Surrounding the alveoli are intricate networks of
capillaries.
Oxygen passes into the bloodstream via the alveoli by diffusion while carbon dioxide
passes out of the body through the alveoli by diffusion.
There are more than 300 million alveoli per lung which provides a huge surface area
to facilitate the gas exchange.
