Respiratory system enables living organisms to live necessary gas exchange. In humans and other mammals are main parts of the respiratory system of the lungs. Respiratory system is responsible for the intake of air into and out of the lungs during breathing, that is for gas exchange.

Respiratory system of humans and animals can be divided into two functionally distinct parts.The first inlet portion has the task of heating, humidification and purification of air entering the lungs. Second, respiratory part, is responsible for the exchange of oxygen and carbon dioxide between the blood and air. Other important functions include maintaining the balance of the internal environment (pH), and vocalization (human formation of speech).