THE RESPIRATORY SYSTEM
Cells need oxygen to release the energy that is stored in food molecules such as glucose.
Carbon dioxide is also produced when cells carry out this function.
Gas exchange is the process of taking in oxygen and
releasing carbon dioxide. It occurs in your lungs.
First, air enters the throat and nasal cavities where
dirt gets trapped by mucus and tiny hairs
Next air passes by the pharynx and then to the larynx.
The larynx contains your vocal cords.
The air then travels down the trachea which connects
to the lungs. The tubes in the lungs become smaller
called bronchi and then they get even smaller so that
air can be carried to all parts of the lungs.
Once the air reaches the lungs, the exchange of gases occurs between the blood and the alveoli.
Alveoli are tiny air sacs whose walls are made up of a single layer of cells.
The alveoli are surrounded by tiny blood vessels called capillaries.
Oxygen diffuses from the alveoli into these capillaries (into your bloodstream).
Carbon dioxide diffuses from the capillaries into the lungs (to get rid of the CO2)