Nokea
Most oxygen in the blood is transported
- A. as gas dissolved in plasma
- B. as oxyhemoglobin
- C. as carboxyhemoglobin
- D. as bicarbonate
Correct Answer: B
Rationale: The correct answer is B: as oxyhemoglobin. Oxygen is primarily carried in the blood by binding to hemoglobin in red blood cells to form oxyhemoglobin. This allows for efficient transport of oxygen to tissues. Choice A is incorrect because only a small amount of oxygen is dissolved in plasma. Choice C is incorrect as carboxyhemoglobin refers to carbon monoxide binding to hemoglobin, not oxygen. Choice D is incorrect as the majority of carbon dioxide is transported as bicarbonate, not oxygen.
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You are evaluating and assessing a client diagnosed with chronic emphysema. The client is on oxygen at a flow rate of 5 L/min by nasal cannula. Which finding concerns you immediately?
- A. The client has fine bibasilar crackles.
- B. The client's respiratory rate is 8 breaths/minute.
- C. The client sits up and leans over the nightstand.
- D. The client has a large barrel chest.
Correct Answer: B
Rationale: The correct answer is B. A respiratory rate of 8 breaths/minute is abnormally low and indicates potential hypoventilation or respiratory depression, which is concerning in a client with chronic emphysema. Fine crackles (A) and barrel chest (D) are common findings but not immediately alarming. Sitting up and leaning forward (C) is a compensatory mechanism for easier breathing.
The partial pressure of oxygen in atmospheric air at sea level is
- A. greater than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest
- B. less than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest
- C. equal to the partial pressure of oxygen in atmospheric air at the top of Mt. Everest
- D. equal to the sum of partial pressures from carbon dioxide and nitrogen
Correct Answer: A
Rationale: The correct answer is A because the partial pressure of oxygen decreases with increasing altitude due to the decrease in atmospheric pressure. At sea level, the atmospheric pressure is higher, resulting in a higher partial pressure of oxygen compared to the top of Mt. Everest. Choice B is incorrect because the partial pressure of oxygen is not higher at higher altitudes. Choice C is incorrect because the partial pressure of oxygen is not equal at sea level and Mt. Everest. Choice D is incorrect because the question specifically asks about the partial pressure of oxygen only, not the sum of partial pressures from other gases.
Volume of air left after maximum forceful expiration in human lung is
- A. Total lung capacity
- B. Residual volume
- C. Vital capacity
- D. Tidal volume
Correct Answer: B
Rationale: The correct answer is B: Residual volume. After maximum forceful expiration, residual volume is the volume of air left in the lungs to prevent lung collapse. Total lung capacity (A) is the maximum amount of air the lungs can hold. Vital capacity (C) is the maximum amount of air that can be exhaled after a maximum inhalation. Tidal volume (D) is the volume of air moved in and out of the lungs during normal breathing, not after a forceful expiration.
Which of the following structures protects the lower respiratory system from food and fluid bolus during swallowing?
- A. larynx.
- B. epiglottis.
- C. vestibule.
- D. pharynx.
Correct Answer: B
Rationale: The correct answer is B: epiglottis. The epiglottis is a flap of tissue that covers the opening of the trachea during swallowing, preventing food and fluid from entering the lower respiratory system. This mechanism ensures that the airway remains clear and protects the lungs from aspiration. The other choices are incorrect because:
A: The larynx is involved in sound production and air passage but does not specifically protect the lower respiratory system during swallowing.
C: The vestibule is the space within the nasal cavity but does not play a direct role in protecting the lower respiratory system during swallowing.
D: The pharynx is a passageway for both food and air but does not specifically prevent food and fluid bolus from entering the lower respiratory system during swallowing.
The most important chemical regulator of respiration is
- A. oxygen
- B. carbon dioxide
- C. bicarbonate ion
- D. sodium ion
Correct Answer: B
Rationale: The correct answer is B: carbon dioxide. Carbon dioxide is the most important chemical regulator of respiration as it directly affects the respiratory rate and depth. An increase in carbon dioxide levels in the blood triggers the body to increase respiration to expel the excess carbon dioxide. Conversely, a decrease in carbon dioxide levels signals the body to decrease respiration. Oxygen (choice A) is important for cellular respiration but does not directly regulate breathing. Bicarbonate ion (choice C) and sodium ion (choice D) do not play a direct role in regulating respiration.