Final answer:
Emphysema is a respiratory system disorder located in the respiratory section of an alphabetic index.
Step-by-step explanation:
Emphysema is a disease that affects the respiratory system. In the alphabetical index of a medical or health textbook, you would find emphysema under the section that deals with the organs and diseases of the respiratory system. Emphysema specifically involves the damage and enlargement of the air sacs (alveoli) in the lungs, leading to breathing difficulties.
Chapter 16 of the textbook, which describes the structure and function of the respiratory system, also addresses disorders of the respiratory system, including emphysema. This can be found in sections detailing the lungs, gas exchange, and breathing processes - making it clear that emphysema is associated with the respiratory system.