The system consists of the following main parts. They perform all the major functions of the respiratory system.

Structure of respiratory system


It is one of the external respiratory parts. The nose consists of the nasal cavity. It is the main opening which leads to the rest of the respiratory system. The nasal cavity is hollow and contains mucus and hair. The primary function of the nose is to make the air warm and moist. The mucus and hair also filter the air before it enters the lungs. So, a nose is of great help in the overall role of the respiratory system.


The mouth is the second opening leading to the lungs. It supplements the function of the nasal cavity. Alternatively, it also acts as a substitute in case of nasal blockage.


The pharynx is a muscular funnel. It transports air from the nasal cavity to the larynx.


The common name for trachea is the windpipe. It is five inches long and consists of C shaped rings of cartilage. It provides passage to the air when it passes from the larynx to the bronchi.


The trachea divides into two large air passages which are the bronchi. These bronchi carry air into the lungs.


The human body contains one pair of lungs. These are the major organ of the respiratory system. This is where the exchange of gases takes place between the respiratory system and the blood. The lungs consist of tiny air sacs, which are the alveoli.

These sacs provide a large surface area. So, there are the exchanges of the considerable volume of gas within seconds.


The diaphragm plays an important role in the functions of the respiratory system. It is a muscle which helps the lungs expand and contract for the exchange of gases.