To survive, animals must obtain
oxygen and dispose of carbon dioxide. This exchange of gases between
an organism and its environment is accomplished by the process of
All animals ultimately rely on
diffusion for gas exchange, but only the simplest and smallest
organisms use diffusion alone. Complex animals have evolved a number
of different adaptations for gas exchange. These specialized
structures include the skin, tracheal tubes, gills, and lungs.
In this Lesson, we'll explore
the different types of respiratory systems and the components of
these systems. Well also study the structure and physiology of
the human respiratory system, including the mechanism and control of
Well conclude by looking at
the role of breathing in the exchange of oxygen and carbon dioxide
between the air and the circulatory system, and how these gases are
transported throughout the body.