Nursing practice questions with comprehensive rationales
NurseDive Free Nursing Practice Question
How is the majority of oxygen transported in the blood?
A. Bound to the globin portion of hemoglobin
Bound to the globin portion of hemoglobin: Oxygen binds the heme (iron) portion, not the globin protein chains
B. Dissolved in the plasma
Dissolved in the plasma: Only a small fraction (~1.5%) of O₂ is dissolved in plasma
C. Bound to the heme portion of hemoglobin
Bound to the heme portion of hemoglobin: Most O₂ (~98–99%) is carried as oxyhemoglobin bound to heme iron
D. In the form of bicarbonate and water
In the form of bicarbonate and water: Bicarbonate transport applies to CO₂, not O₂
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Full Explanation
A. Bound to the globin portion of hemoglobin: Oxygen binds the heme (iron) portion, not the globin protein chains
B. Dissolved in the plasma: Only a small fraction (~1.5%) of O₂ is dissolved in plasma
C. Bound to the heme portion of hemoglobin: Most O₂ (~98–99%) is carried as oxyhemoglobin bound to heme iron
D. In the form of bicarbonate and water: Bicarbonate transport applies to CO₂, not O₂
Similar Questions
A mother and two young children are found passed out in their apartment, where a space heater is on. Emergency medical technicians suspect carbon monoxide poisoning. Why is carbon monoxide dangerous?
A. It causes extreme depression of the respiratory rate.
It causes extreme depression of the respiratory rate: CO binds hemoglobin and impairs O₂ delivery; respiratory depression is not the primary danger
B. It drastically decreases the pH of the blood.
It drastically decreases the pH of the blood: CO poisoning does not primarily cause a dramatic blood pH drop
C. It binds to the oxygen-binding site on hemoglobin, so the O2-carrying ability of the blood is reduced.
It binds to the oxygen-binding site on hemoglobin, so the O₂-carrying ability of the blood is reduced: CO binds avidly to hemoglobin’s heme sites, displacing O₂ and reducing oxygen carriage and delivery
D. It triggers hyperventilation, causing a severe drop in PCO2 and increase in blood pH.
It triggers hyperventilation, causing a severe drop in PCO₂ and increase in blood pH: Hyperventilation is not the main mechanism of CO toxicity
Full Explanation
A. It causes extreme depression of the respiratory rate: CO binds hemoglobin and impairs O₂ delivery; respiratory depression is not the primary danger
B. It drastically decreases the pH of the blood: CO poisoning does not primarily cause a dramatic blood pH drop
C. It binds to the oxygen-binding site on hemoglobin, so the O₂-carrying ability of the blood is reduced: CO binds avidly to hemoglobin’s heme sites, displacing O₂ and reducing oxygen carriage and delivery
D. It triggers hyperventilation, causing a severe drop in PCO₂ and increase in blood pH: Hyperventilation is not the main mechanism of CO toxicity
The opening between the true vocal cords is called the
A. thryoid cartilage
Thyroid cartilage: Thyroid cartilage is a laryngeal cartilage (Adam’s apple), not the opening between the cords
B. cricoid cartilage
Cricoid cartilage: Cricoid cartilage is a ring below the thyroid cartilage, not the opening between vocal cords
C. alveoli
Alveoli: Alveoli are air sacs in the lungs, unrelated to vocal cord anatomy
D. glottis
Glottis: The glottis is the opening between the true vocal cords
Full Explanation
A. Thyroid cartilage: Thyroid cartilage is a laryngeal cartilage (Adam’s apple), not the opening between the cords
B. Cricoid cartilage: Cricoid cartilage is a ring below the thyroid cartilage, not the opening between vocal cords
C. Alveoli: Alveoli are air sacs in the lungs, unrelated to vocal cord anatomy
D. Glottis: The glottis is the opening between the true vocal cords
What causes air to move into the lungs during inspiration?
A. Muscle contraction of upper airways
Muscle contraction of upper airways: Upper airway muscle movement does not create the main pressure change driving inspiration
B. Partial pressure gradients for oxygen and carbon dioxide
Partial pressure gradients for oxygen and carbon dioxide: Partial pressure gradients drive gas diffusion across membranes, not bulk airflow into lungs
C. Pressure gradient between atmosphere and alveoli
Pressure gradient between atmosphere and alveoli: Contraction of the diaphragm/intercostals lowers intrapulmonary pressure relative to atmospheric pressure, causing air to flow in
D. Concentration gradients for oxygen and carbon dioxide
Concentration gradients for oxygen and carbon dioxide: Concentration gradients drive diffusion at the alveolar–capillary level, not the gross movement of air into the lungs
Full Explanation
A. Muscle contraction of upper airways: Upper airway muscle movement does not create the main pressure change driving inspiration
B. Partial pressure gradients for oxygen and carbon dioxide: Partial pressure gradients drive gas diffusion across membranes, not bulk airflow into lungs
C. Pressure gradient between atmosphere and alveoli: Contraction of the diaphragm/intercostals lowers intrapulmonary pressure relative to atmospheric pressure, causing air to flow in
D. Concentration gradients for oxygen and carbon dioxide: Concentration gradients drive diffusion at the alveolar–capillary level, not the gross movement of air into the lungs