The medical nurse who works on a pulmonology unit is aware that several respiratory conditions can affect lung tissue compliance. The presence of what condition would lead to an increase in lung compliance?

Correct Answer: A

Rationale: The correct answer is A: Emphysema. Emphysema leads to an increase in lung compliance due to the destruction of alveolar walls, resulting in decreased elastic recoil. This decreased recoil makes it easier for the lungs to expand and increases overall lung compliance. Incorrect choices: B: Pulmonary fibrosis - Pulmonary fibrosis causes lung tissue scarring and stiffening, resulting in decreased lung compliance. C: Pleural effusion - Pleural effusion is an accumulation of fluid in the pleural space, which can restrict lung expansion and decrease lung compliance. D: Acute respiratory distress syndrome (ARDS) - ARDS causes inflammation and fluid buildup in the lungs, leading to decreased lung compliance due to increased stiffness and reduced ability to expand.

Correct Answer: B

Rationale: The correct answer is B: intrapleural pressure. Intrapleural pressure remains negative throughout the respiratory cycle due to the opposing forces of the elastic recoil of the lungs and the chest wall. This negative pressure keeps the lungs inflated and facilitates breathing. In contrast, intrapulmonary (A) and intra-alveolar (C) pressures fluctuate during inhalation and exhalation, becoming positive and negative, respectively. Atmospheric pressure (D) remains relatively constant and serves as the reference point for pressure changes in the respiratory system.

Correct Answer: B

Rationale: The correct answer is B: bound to hemoglobin. This is because hemoglobin is the protein in red blood cells that carries oxygen from the lungs to tissues throughout the body. Oxygen binds to the iron atoms in hemoglobin, forming oxyhemoglobin. This accounts for the majority of oxygen transport in the blood. A: Dissolved in plasma is incorrect as only a small fraction of oxygen is carried this way. C: In ionic form as a solute in plasma is incorrect as oxygen is not typically found in ionic form in the blood. D: Bound to the same protein as carbon dioxide is incorrect as oxygen binds to hemoglobin, while carbon dioxide primarily binds to different proteins such as carbonic anhydrase.

Correct Answer: B

Rationale: The correct answer is B: changes in PCO2. Chemoreceptors in the carotid and aortic bodies detect levels of oxygen, carbon dioxide, and pH in the blood. Blocking afferent action potentials from these chemoreceptors would specifically interfere with detecting changes in PCO2, as these receptors primarily respond to alterations in CO2 levels. This interference would disrupt the brain's ability to regulate breathing in response to changes in PCO2, leading to potential respiratory problems. Choices A and C are incorrect because chemoreceptors primarily respond to CO2 levels, not O2 or pH. Choice D is incorrect because changes in blood pressure are primarily detected by baroreceptors, not chemoreceptors in the carotid and aortic bodies.

Correct Answer: A

Rationale: The correct answer is A: alveoli. The alveoli are not part of the bronchial tree; they are the tiny air sacs at the end of the bronchial tree where gas exchange occurs. The bronchial tree consists of the bronchi, terminal bronchioles, and respiratory bronchioles, which are responsible for conducting air into the lungs. Alveoli are located at the end of the respiratory bronchioles and are where oxygen is absorbed into the bloodstream and carbon dioxide is released. Therefore, alveoli are not considered part of the bronchial tree.