A nurse is caring for a client with emphysema who is receiving oxygen. The nurse assesses the oxygen flow rate to ensure that it does not exceed:

Correct Answer: B

Rationale: The correct answer is B: 3 L/min. Emphysema patients have compromised lung function, so high oxygen flow rates can lead to oxygen toxicity. 3 L/min is the recommended maximum flow rate to prevent oxygen toxicity while still providing adequate oxygenation. Choices A, C, and D exceed the safe limit and can lead to hyperoxia, absorption atelectasis, and other complications in emphysema patients. Therefore, B is the correct choice to ensure optimal oxygen therapy without causing harm.

Correct Answer: A

Rationale: The correct answer is A: 21 percent. Air is composed of about 21% oxygen, 78% nitrogen, and small amounts of other gases. This composition is crucial for sustaining life on Earth. Choice B is incorrect as it represents the percentage of nitrogen in the air. Choices C and D are also incorrect as they are the approximate percentages of carbon dioxide and argon in the air, respectively. Therefore, the correct answer is A as it accurately reflects the oxygen content in the air.

Correct Answer: D

Rationale: The correct answer is D because the rate and depth of breathing are controlled by a respiratory center in the brainstem, which includes the medulla and pons. The medulla regulates the basic rhythm of breathing, while the pons helps adjust the rate and depth based on input from chemoreceptors and other factors. Choice A is incorrect because chemoreceptors in arterial walls primarily detect changes in blood pH and CO2 levels, not directly control breathing. Choice B is incorrect as baroreceptors in the diaphragm are more related to detecting stretch and pressure changes, not regulating breathing. Choice C is incorrect as the partial pressure of O2 in the atmosphere does not directly control breathing but rather influences oxygen exchange in the lungs.

Correct Answer: B

Rationale: The correct answer is B, Bucco-pharyngeal cavity. The glottis is the opening between the vocal cords in the larynx, which is located in the upper part of the respiratory tract. The bucco-pharyngeal cavity is the part of the oral cavity that leads to the pharynx, where the glottis is situated. The diaphragm is a muscle separating the thoracic and abdominal cavities, and the trachea is a tube connecting the larynx to the bronchi. Therefore, the glottis is not located in the diaphragm or trachea.

Correct Answer: D

Rationale: The correct answer is D (0.03% and 4.0%). The inspired air contains approximately 0.03% CO2, as the atmosphere has a low CO2 concentration. During expiration, the CO2 concentration in the air increases due to the removal of oxygen and the addition of CO2 from cellular respiration, resulting in an average of around 4.0% CO2 in expired air. Choices A, B, and C are incorrect because they do not accurately reflect the typical CO2 concentrations in inspired and expired air in human beings.