The C in COPD stands for:

A. A pneumothorax occurs when there is a collapse of the lung due to air entering the pleural cavity, but this is not directly related to the lungs dropping below atmospheric pressure.
B. Air flows out of the lungs when the pressure inside the lungs is higher than atmospheric pressure (e.g., during exhalation).
C. When the pressure in the lungs drops below atmospheric pressure, it creates a vacuum effect, causing air to flow into the lungs during inhalation. This is how normal breathing works.
D. Bronchiolar constriction can cause respiratory distress, but it is not directly linked to a drop in lung pressure. Instead, constriction happens due to factors like asthma or allergies, not pressure changes.

A. Bronchodilators are medications specifically designed to relax the muscles around the airways, making it easier to breathe by increasing airflow. They are commonly used in conditions like asthma and chronic obstructive pulmonary disease (COPD).
B. Doxycycline is an antibiotic used to treat bacterial infections. It has no direct effect on airway muscles or airflow.
C. ACE inhibitors are used primarily to treat high blood pressure and heart failure. They do not act on the airways and are not used to improve airflow.
D. Anti-androgen therapy is used to reduce levels of male hormones, typically in the treatment of prostate cancer or hormone-sensitive conditions. It has no role in bronchodilation or respiratory therapy.