Aminophylline (theophylline) is prescribed for a client with acute bronchitis. A nurse administers the medication, knowing that the primary action of this medication is to?

Correct Answer: C

Rationale: The correct answer is C: Relax smooth muscles of the bronchial airway. Aminophylline (theophylline) is a bronchodilator that works by relaxing the smooth muscles in the bronchial airways, which helps to open up the airways and improve airflow. This action helps to relieve bronchospasm, which is common in conditions like acute bronchitis. Promoting expectoration (A) and suppressing cough (B) are not the primary actions of aminophylline, although they may be secondary effects. Preventing infection (D) is unrelated to the mechanism of action of aminophylline in treating acute bronchitis.

Correct Answer: B

Rationale: During inhalation, the diaphragm contracts and moves downward, increasing the volume of the thoracic cavity. This decrease in pressure within the thoracic cavity creates a pressure gradient, causing air to flow into the lungs where the pressure is now higher. Choice B is correct because the pressure in the thoracic cavity is indeed less than the pressure within the lungs during inhalation. Choices A, C, and D are incorrect because during inhalation, the pressure in the thoracic cavity decreases, the diaphragm moves downward and flattens, and the chest cavity volume increases to allow for air intake.

Correct Answer: B

Rationale: The correct answer is B: internal respiration. This process refers to the exchange of gases between blood and body cells. Pulmonary ventilation (A) is the process of breathing, moving air in and out of the lungs. External respiration (C) is the exchange of gases between the lungs and blood. Cellular respiration (D) is the process where cells use oxygen to produce energy. Internal respiration best describes the exchange of gases at the cellular level.

Correct Answer: B

Rationale: The correct answer is B because if the thoracic wall is punctured but not the lungs, air will enter the pleural cavity causing a pneumothorax. This leads to lung collapse and can result in death due to impaired gas exchange. Choices A and C are incorrect as the lungs do not get inflated and breathing rate does not decrease. Choice D is incorrect as the breathing rate actually increases in response to the decreased lung function.

Correct Answer: C

Rationale: The correct answer is C: Vital capacity. Vital capacity is the maximum amount of air a person can expel from the lungs after a maximum inhalation. It is the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume. Residual volume (A) is the air left in the lungs after maximum exhalation. Tidal volume (B) is the amount of air inhaled and exhaled during normal breathing. Lung volume (D) is a general term and not a specific measure of air quantity. Thus, vital capacity is the best choice as it accounts for the maximum air that can be expired after a deep inhalation.