Chapter Questions
Diagram the four basic steps of $\mathrm{O}_{2}$ transport from an animal's respiratory medium (air or water) to its cells.
Describe two features of the gills of aquatic animals that favor diffusion of $\mathrm{O}_{2}$ and $\mathrm{CO}_{2}$.
Name two differences in the physical properties of water and of air that affect gas exchange in aquatic versus terrestrial animals.
Explain how the tracheal respiratory system of insects enables high metabolic rates.
Explain how gill respiration is facilitated by unidirectional water flow, whereas lung ventilation can depend on bidirectional airflow.
Describe the pressure changes that are needed to draw air into the lungs and to expel air out of the lungs.
Explain how cooperative binding by hemoglobin facilitates $\mathrm{O}_{2}$ uptake into blood.
Explain how the branching of larger arteries into many smaller vessels affects the rate of and resistance to blood flow in the smaller vessels.
Diagram the path of blood flow through the heart, lungs, and body of a fish and of a mammal or bird.
Describe two mechanisms by which the cardiac output of an animal's heart can be adjusted and indicate which is more important for increasing cardiac output in mammals and which is more important in fish.