The respiratory system performs three important functions for the air we breathe: warming it, moistening it, and filtering it. It is made up of the nasal passage, pharynx, epiglottis, larynx, trachea, bronchi, bronchioles, and alveoli. The lungs contain no muscle tissue, so breathing is driven by the diaphragm and intercostal muscles increasing and decreasing the space in the chest cavity. Cellular respiration uses oxygen to extract energy from foods through the breakdown of glucose.

1. Respiratory System Very nice!