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Multiple Choice
Inadequate exhalation of carbon dioxide can cause which of the following conditions?
A
Metabolic alkalosis
B
Respiratory alkalosis
C
Metabolic acidosis
D
Respiratory acidosis
Verified step by step guidance
1
Understand the relationship between carbon dioxide (CO2) and blood pH: CO2 is transported in the blood and reacts with water to form carbonic acid (H2CO3), which dissociates into hydrogen ions (H⁺) and bicarbonate ions (HCO₃⁻). This reaction is represented as: . An increase in CO2 levels leads to more H⁺ ions, lowering blood pH (acidosis).
Identify the role of exhalation in regulating CO2 levels: During normal respiration, CO2 is exhaled, preventing its accumulation in the blood. If exhalation is inadequate, CO2 builds up, shifting the equilibrium of the reaction above to produce more H⁺ ions, causing a decrease in pH.
Differentiate between respiratory and metabolic causes of pH imbalance: Respiratory conditions are related to changes in CO2 levels due to lung function, while metabolic conditions involve changes in bicarbonate (HCO₃⁻) or other metabolic factors. In this case, inadequate exhalation of CO2 directly implicates a respiratory cause.
Define respiratory acidosis: This condition occurs when CO2 accumulates in the blood due to hypoventilation (inadequate exhalation), leading to a decrease in blood pH. It is characterized by an increase in CO2 levels (hypercapnia) and a corresponding drop in pH.
Conclude that the correct answer is respiratory acidosis, as it directly results from the inadequate exhalation of CO2, leading to an increase in blood acidity.