The human respiratory system is very complex when compared to other animals as well as in sects. The respiratory system of an amphibian includes the skin that exchanges oxygen and carbon dioxide by process of diffusion through the skin. In case of plants, the respiratory system includes stomata that are found on the underside of the leaves. It is through these stomata that the plants receive their supply of carbon dioxide.
The respiratory system in human and all other mammals is made of the lungs, trachea, bronchioles and alveoli. Several molecules of oxygen and carbon dioxide are exchanged with the aid of the alveoli. The process of exchange of gases is known as diffusion. In the humans the environmental gases are transported to the blood circulating in the human body. The oxygen that is inhaled by the respiratory system is converted into energy and the waste [products along with carbon dioxide are exhaled through the lungs into the environment.
Ventilation, control of ventilation, inhalation, exhalation and gas exchange are some of the functions of the human respiratory system. There are various diseases affecting the function of the respiratory system and these include bronchitis, asthma, alveolar damage, fibrosis, pulmonary edema, embolism and pulmonary hypertension. Various infections include pneumonia, tuberculosis, exposure to asbestos and other pollutants can also cause anomalies in the normal respiratory function.