Types of Respiratory Organs
Respiratory organs may be of the following types:
Figure: Some aquatic animals and animals that maintain moist skins, can exchange gases directly through their integuments
Insects have a special respiratory system. Small openings on the insect's body surface connected to small tubes or trachea that branch and spread throughout the body. The gases diffuse through these branches directly into the cells. Generally gills are for aquatic breathing and lungs for breathing air. We shall now consider specific kinds of respiratory organs employed by animals that live in water and on land.