The nurse recognizes that a rising PaCO2 level in a COPD patient means that:

Correct Answer: C

Rationale: Step-by-step rationale for why answer C is correct: 1. In COPD, impaired lung function leads to inadequate ventilation and CO2 retention. 2. Rising PaCO2 indicates inadequate CO2 removal, leading to respiratory acidosis. 3. Respiratory acidosis is characterized by low pH and high PaCO2 levels. 4. This condition can worsen COPD symptoms and lead to respiratory failure. Summary: Option A is incorrect as rising PaCO2 indicates hypoxemia. Option B is incorrect as ventilation-perfusion imbalance worsens in COPD. Option D is incorrect as anticholinergics do not directly affect PaCO2 levels in COPD.

Correct Answer: A

Rationale: The correct answer is A: carbon dioxide concentrations are high. When carbon dioxide levels are high, it leads to a decrease in blood pH, triggering hemoglobin to release oxygen more readily through the Bohr effect. This is a physiological response to maintain homeostasis. The other choices (B, C, D) do not directly affect the release of oxygen from hemoglobin.

Correct Answer: C

Rationale: The correct answer is C: diffusion. During internal and external respiration, gases move from areas of high concentration to low concentration through passive diffusion. This process is driven by the concentration gradient, allowing gases like oxygen and carbon dioxide to exchange in the lungs and tissues. Osmosis (A) is the movement of water across a semipermeable membrane, not gases. Active transport (B) requires energy and moves substances against their concentration gradient, which is not how gases move during respiration. Endocytosis (D) is a process where cells engulf substances by forming vesicles, not how gases are exchanged in respiration.

Correct Answer: A

Rationale: The vital capacity of lungs is the maximum amount of air a person can exhale after a maximum inhalation. The average vital capacity for an adult human is typically between 3000-4500 ml. This range allows for efficient gas exchange in the lungs. Choice B (1500-1800 ml) and Choice C (2000-2500 ml) fall below the average vital capacity, indicating limited lung capacity. Choice D (500-1000 ml) is significantly low and would not support normal respiratory function. Therefore, Choice A (3000-4500 ml) is the correct answer as it aligns with the average vital capacity range for an average human.

Correct Answer: A

Rationale: The correct answer is A: Flat. During inspiration, the muscles attached to the diaphragm contract, causing it to flatten. This action increases the volume of the thoracic cavity, allowing air to rush into the lungs. The diaphragm moving downward creates a larger space for the lungs to expand. Choices B, C, and D are incorrect because the diaphragm does not become dome-shaped, concave, or rotate during inspiration. The key concept here is understanding the role of the diaphragm in the breathing process and how its contraction affects the shape of the thoracic cavity.