Describe the conservation of bicarbonate ions in the renal system and compare it to the control of blood carbonic acid levels through the respiratory system.

Explain how the stomach is protected from self-digestion and why this is necessary.

Compare and contrast the conducting and respiratory zones.

A smoker develops damage to several alveoli that then can no longer function. How does this affect gas exchange?

Explain how the enteric nervous system supports the digestive system. What might occur that could result in the autonomic nervous system having a negative impact on digestion?