Humans need a respiratory system because it is made up of organs that allow them to breathe. Breathing delivers oxygen to the body and takes away carbon dioxide. Every cell in the body needs oxygen to obtain energy from food.
The lungs and heart work together to ensure that every cell in the body acquires enough oxygen to function properly. Delivery of oxygen to the blood through breathing is the primary function of the respiratory system. Moreover, the respiratory system expels carbon dioxide, which is a harmful waste product of cells. This gas is dangerous when it builds up in the body. The blood carries carbon dioxide from the cells to the lungs, which get rid of the gas by exhaling. This process of exchanging gases is the essential function of the respiratory system.
Respiration is performed through the nose, mouth, trachea, lungs and diaphragm. Inhalation or inspiration is the process of taking oxygen into the lungs, while the process of getting it out is called exhalation or expiration. The respiratory system filters any pollutant or foreign organism that enters through the nose and mouth to ensure that the air the body breathes is clean. The respiratory tract and nasal passageways also have small hairs, called cilia, which filter out dust and particles in the air that enters the body through the nose.
Aside from the lungs, other parts of the respiratory system include the trachea, bronchi and diaphragm.