A patient is scheduled to have excess pleural fluid aspirated with a needle in order to relieve her dyspnea. The patient inquires about the normal function of pleural fluid. What should the nurse describe?

Correct Answer: D

Rationale: The correct answer is D: It lubricates the movement of the thorax and lungs. Pleural fluid acts as a lubricant between the layers of the pleura, reducing friction and allowing smooth movement during respiration. This function is crucial for the efficient expansion and contraction of the lungs during breathing. Explanation: 1. A (It allows for full expansion of the lungs within the thoracic cavity): While pleural fluid does contribute to lung expansion, its main role is not to solely allow for full expansion. 2. B (It prevents the lungs from collapsing within the thoracic cavity): This is incorrect as the pleural pressure, rather than the pleural fluid, prevents lung collapse. 3. C (It limits lung expansion within the thoracic cavity): This is incorrect as pleural fluid actually facilitates lung expansion by reducing friction.

Correct Answer: A

Rationale: The correct answer is A: 40 mm Hg. In peripheral tissues, oxygen is delivered by the blood through capillaries. The partial pressure of oxygen in the interstitial space of peripheral tissues is lower than in the blood, around 40 mm Hg. This allows for the diffusion of oxygen from capillaries to cells. Choice B (45 mm Hg) and C (50 mm Hg) are slightly higher pressures and would not promote efficient oxygen diffusion. Choice D (70 mm Hg) is closer to arterial blood oxygen levels and would not allow sufficient oxygen release to tissues. Thus, the correct answer is A as it reflects the physiological conditions necessary for effective oxygen delivery to cells.

Correct Answer: D

Rationale: The correct answer is D: oxygen-hemoglobin saturation curve. This is because the oxygen-hemoglobin saturation curve graphically depicts the relationship between the saturation of hemoglobin with oxygen and the partial pressure of oxygen. This curve helps visualize factors affecting oxygen release, such as pH, temperature, and carbon dioxide levels. A: Spirograph is a tool used for drawing geometric shapes and has no relevance to hemoglobin oxygen release. B: Pulmonary volume chart is used to measure lung volumes and capacities, not specifically related to hemoglobin oxygen release. C: Respiratory cycle chart may show breathing patterns but does not directly visualize factors affecting oxygen release from hemoglobin. In summary, the oxygen-hemoglobin saturation curve is the most appropriate tool for visualizing factors influencing oxygen release from hemoglobin, making it the correct choice over the other options.

Correct Answer: D

Rationale: The correct answer is D: Alveoli are expanded. Prior to birth, the alveoli in the lungs are collapsed, and they begin to expand and develop after birth when the baby starts breathing air. A: Pulmonary arterial resistance is high due to blood flow bypassing the lungs. B: Pulmonary vessels are collapsed to prevent blood flow in the fetal lungs. C: The rib cage is compressed in the womb due to the limited space, but it expands after birth to allow for lung expansion.

Correct Answer: B

Rationale: The correct answer is B: Edema. In heart failure patients, fluid buildup in the lungs is known as pulmonary edema. This occurs due to the heart's inability to pump effectively, leading to fluid leaking into the lungs' air sacs. Ascites (A) is fluid buildup in the abdomen, not the lungs. Pleurisy (C) is inflammation of the lining around the lungs, not fluid buildup. Effusion (D) refers to fluid accumulation in body cavities like the chest or abdomen, but it is not specific to the lungs like pulmonary edema.