After studying this chapter, you should be able to accomplish the following outcomes.

Gas Exchange Surfaces

1. Name the three events that occur during respiration.
2. Contrast the respiratory exchange surface of a hydra, an earthworm, a fish, an insect, and a vertebrate and show that each is suitable to the environment.
3. Show that countercurrent flow increases the efficiency of gills in extracting oxygen from water.
4. Explain how tracheal system in insects accomplishes ventilation and exchange.
5. Trace the path of air in the human respiratory system and discuss the cleansing role of the tracheal lining.

6. Describe the mechanics of ventilation in humans and compare to birds.
7. Explain how breathing rate in humans can be modified.
8. Discuss the transport of O₂ and CO₂; internal and external respiration; and the regulation of blood pH.

9. List and discuss lower respiratory tract infections and disorders including lung cancer.