Pathway of Air

Introduction to the Respiratory System

The respiratory system allows us to breathe in oxygen and breathe out carbon dioxide.
The oxygen we breathe in is necessary for our bodies to produce energy.
It also serves to remove the waste product carbon dioxide that our body generates as it uses up energy.

When you breathe in through your nose or mouth, the air travels down the windpipe, also known as the trachea.
The trachea branches into two tubes called bronchi, one entering each lung.
Inside the lungs, the bronchi divides into smaller air passages known as bronchioles. These bronchioles end in tiny air sacs called alveoli.
The alveoli is where the exchange of gases takes place. The oxygen moves from the alveoli into the blood vessels while carbon dioxide waste moves from the blood vessels into the alveoli.
The carbon dioxide is then expelled from the body when we breathe out.

The diaphragm, a dome-shaped muscle located at the base of the lungs, plays a crucial role in breathing.
When we breathe in, the diaphragm contracts and flattens, creating a vacuum that causes a rush of fresh air into the lungs.
When we breathe out, the diaphragm relaxes and returns to its dome-like shape, pushing out the air laden with carbon dioxide.

The capillaries play an essential role in this gas exchange process.
They are tiny blood vessels that line the walls of the alveoli.
They are so thin and permeable that oxygen can easily pass through them from the alveoli into the bloodstream.
Similarly, the waste carbon dioxide can transfer from the bloodstream into the alveoli before being exhaled.