is the outermost opening of this system. There are
2 nostrils through which air is inhaled and exhaled.
The air passing through the nose is filtered by the
hair inside and it is warmed and moisturized by contact
with the inner curved surfaces. Through the throat,
the air enters the trachea or vent pipe, which is
further divided into two main branches called Bronchus.
The Bronchus is further divided in to sub branches
in the Thoracic Cavity. This cavity is extended to
the Diaphragm at the bottom and is covered by the
ribs from the side. The inhaled air passing through
Bronchus reaches at terminal bronchiole and finally
in the alveoli where the exchange of oxygen and Carbon
dioxide takes place and air is exhaled out of the
body through the same passage.