Inhalation and Exhalation

-Decreased volume of chest

-Higher pressure in the chest

-Ribs fall as the intercostal muscles contract

-Diaphragm moves up

-Air travels from the alveoli to the bronchioles, through the bronchi, up the trachea and out of the nasal cavity. 

-Increased volume of chest 

-Lower pressure in the chest

-Ribs move up and out as the intercostal muscles contract

-Diaphragm flattens

-Air travels through the nasal cavity, down the trachea, through the bronchi, down the bronchioles and into the alveoli, where gas exchange takes place.