The ED nurse is assessing a patient complaining of dyspnea. The nurse auscultates the patient's chest and hears wheezing throughout the lung fields. What might this indicate?

Correct Answer: A

Rationale: The correct answer is A: The patient has a narrowed airway. Wheezing throughout the lung fields indicates the presence of narrowed airways, often due to conditions like asthma or chronic obstructive pulmonary disease (COPD). Wheezing is caused by turbulent airflow through narrowed airways, leading to a high-pitched whistling sound during expiration. This is a characteristic finding in patients with obstructive airway diseases. Summary of other choices: B: The patient having pneumonia would typically present with symptoms like fever, cough, and consolidation on auscultation, not wheezing. C: The patient needing physiotherapy may have respiratory muscle weakness or secretion clearance issues but would not typically present with wheezing throughout lung fields. D: The presence of a hemothorax (blood in the pleural space) would manifest as decreased breath sounds and signs of respiratory distress but not wheezing.

Correct Answer: B

Rationale: The correct answer is B: epiglottis. The epiglottis is a flap of tissue that covers the opening of the trachea during swallowing, preventing food and fluid from entering the lower respiratory system. This mechanism ensures that the airway remains clear and protects the lungs from aspiration. The other choices are incorrect because: A: The larynx is involved in sound production and air passage but does not specifically protect the lower respiratory system during swallowing. C: The vestibule is the space within the nasal cavity but does not play a direct role in protecting the lower respiratory system during swallowing. D: The pharynx is a passageway for both food and air but does not specifically prevent food and fluid bolus from entering the lower respiratory system during swallowing.

Correct Answer: A

Rationale: The correct answer is A because the partial pressure of oxygen decreases with increasing altitude due to the decrease in atmospheric pressure. At sea level, the atmospheric pressure is higher, resulting in a higher partial pressure of oxygen compared to the top of Mt. Everest. Choice B is incorrect because the partial pressure of oxygen is not higher at higher altitudes. Choice C is incorrect because the partial pressure of oxygen is not equal at sea level and Mt. Everest. Choice D is incorrect because the question specifically asks about the partial pressure of oxygen only, not the sum of partial pressures from other gases.

Correct Answer: B

Rationale: The correct answer is B: carbon dioxide. Carbon dioxide is the most important chemical regulator of respiration as it directly affects the respiratory rate and depth. An increase in carbon dioxide levels in the blood triggers the body to increase respiration to expel the excess carbon dioxide. Conversely, a decrease in carbon dioxide levels signals the body to decrease respiration. Oxygen (choice A) is important for cellular respiration but does not directly regulate breathing. Bicarbonate ion (choice C) and sodium ion (choice D) do not play a direct role in regulating respiration.

Correct Answer: D

Rationale: The correct answer is D, pseudostratified ciliated columnar epithelium. This type of epithelium lines the conducting portion of the respiratory tract because it contains cilia that help sweep mucus and debris out of the airways. It appears to be stratified but is actually a single layer of cells with varying heights, giving it a pseudostratified appearance. Simple squamous epithelium (choice A) is too thin for the respiratory tract, simple columnar epithelium (choice B) lacks cilia for mucus clearance, and stratified ciliated columnar epithelium (choice C) is not a valid type of epithelium.