Answer to Question 1
A
Feedback:
Smoking can decrease the efficiency of the respiratory system. Nicotine causes a decrease in bronchial diameter, constriction of blood vessels, a decrease in ciliary function (which assists in moving foreign particles out of the respiratory tract), and can destroy lung tissue over time. These factors can all result in a decrease in gas exchange. In addition, many tobacco products contain substances (e.g., tars) that can build up in the lungs. The chest does not become more elastic with increased time of smoking; instead, it loses elasticity and becomes stiffer. Thus, the lungs cannot expand, and the change in the ratio of pressure of oxygen and carbon dioxide in the lungs is the effect of aging on the respiratory system.
Answer to Question 2
C
Feedback:
If a person has a breathing disorder, carbon dioxide can build up in the body, dangerously lowering the blood pH. This condition, called respiratory acidosis, can be caused by disorders, such as emphysema, severe pneumonia, asthma, and pulmonary edema. Too little carbon dioxide in the blood is called respiratory alkalosis. Coughing and sneezing are protective reflexes needed to dislodge materials from the respiratory passages. Pleurisy is an inflammation of the pleura caused by infection, injury, or tumor.