The main function of the respiratory system is to breathe in oxygen and to breathe out carbon dioxide. It also helps in protection from harmful particles and allows the ability to smell and speak. The respiratory system also warms and adds moisture to the air during breathing.

Larynx – it is also called the voice box, it is responsible for vocal sounds and aids in respiration.

Trachea – a tube that serves as the passageway for air, it is also called the windpipe. The trachea divides into left and right bronchi.

Bronchiole – each bronchus is further divided into finer and smaller channels known as bronchioles

Lungs – sac-like structures covered by the pleura, it houses the alveoli where the exchange of gases occurs.