Systems of Gas Exchange
Introduction and Direct Diffusion
Respiratory processes that help organisms exchange O2 and CO2 range from simple direct diffusion to complex respiratory systems.
Skin and Gills and Tracheal Systems
Respiration can occur using a variety of respiratory organs in different animals, including skin, gills, and tracheal systems.
Mammalian Systems and Protective Mechanisms
The mammalian respiratory system equilibrates air to the body, protects against foreign materials, and allows for gas exchange.