The air , passes through the nostrils.
The air that is passing is filtered by the fine hairs , which lines the passage.
Also , mucus helps in lining the passage , in the process involved.
From here , air passes through the throat and then into the lungs
In the throat , rings of cartilage are present , which ensures that the air passage does not collapse.
In the lungs , the passage is divided into very smaller tubes , that terminate into balloon like structures known as alveoli.
Alveoli is a surface that helps in the exchange of gases.
Extensive network of blood vessels is present in the walls of alveoli
When we breathe in , our ribs are lifted and diaphragm is flattened.
As a result , chest cavity becomes larger in size.
Therefore ,the air is sucked into the lungs , expanding the alveoli
Carbon dioxide are released into the alveoli by blood.
Oxygen in the alveolar air is taken by alveolar blood vessels , and is transported to all the cells in the body.
