A patient is being treated for a pulmonary embolism and the medical nurse is aware that the patient suffered an acute disturbance in pulmonary perfusion. This involved an alteration in what aspect of normal physiology?

Correct Answer: D

Rationale: The correct answer is D: Adequate flow of blood through the pulmonary circulation. In a pulmonary embolism, there is a blockage in the pulmonary artery, leading to decreased blood flow to the lungs. This disrupts normal pulmonary perfusion, affecting the oxygenation of blood. The other choices are incorrect because A refers to alveolar function, B relates to respiratory muscle function, and C involves acid-base balance in the blood vessels, none of which directly address the alteration in blood flow seen in a pulmonary embolism.

Correct Answer: D

Rationale: Dalton's law states that in a mixture of gases such as air, the total pressure exerted by the mixture of gases is equal to the sum of the partial pressures of each individual gas in the mixture. This means that each gas in a mixture behaves independently of the others. Therefore, choice D is correct as it directly reflects Dalton's law. Choices A, B, and C are incorrect because they do not accurately describe Dalton's law and its principle of partial pressures in gas mixtures.

Correct Answer: B

Rationale: Low pH (acidic conditions) causes hemoglobin to release oxygen more readily, enhancing oxygen delivery to tissues during internal respiration. External respiration (A) involves gas exchange in the lungs, not affected by pH. Carbon dioxide transport (C) is influenced by pH, but not directly related to oxygen binding. Hemoglobin synthesis (D) is the production of hemoglobin molecules, not influenced by pH during oxygen binding. Therefore, the correct answer is B as low pH primarily affects oxygen release during internal respiration.

Correct Answer: D

Rationale: The correct answer is D: sudden infant death syndrome (SIDS). SIDS is the leading cause of death for children under 1 year old due to unexplained reasons, typically occurring during sleep. A: Motor vehicle accidents are more common in older children. B: Falls are also more common in toddlers who are more mobile. C: Cardiac congenital malformations are a significant cause of death but are not the leading cause in this age group.

Correct Answer: B

Rationale: The correct answer is B: Persistent coughing. In heart failure, fluid may accumulate in the lungs, leading to a persistent cough. High blood pressure (A) is a risk factor for heart failure but not a symptom. Excessive weight loss (C) is not a typical symptom of heart failure; instead, patients may experience weight gain due to fluid retention. Increased energy levels (D) are unlikely in heart failure, as fatigue and weakness are common symptoms. Therefore, the most common symptom of heart failure among the choices given is persistent coughing.