Question

Given below are two statements : Statement I : Respiratory Acidosis is caused by retention of carbon dioxide. The \(PaCO_2\) and \(H^+\) rise. Statement II : In Respiratory alkalosis there is the fall in \(PaCO_2\) and \(H^+\). In the light of the above statements, choose the most appropriate answer from the options given below :

• A. \( \text{Both Statement I and Statement II are correct} \)
• B. \( \text{Both Statement I and Statement II are incorrect} \)
• C. \( \text{Statement I is correct but Statement II is incorrect} \)
• D. \( \text{Statement I is incorrect but Statement II is correct} \)

Hint:

\textbf{Respiratory Physiology: Acid-Base Balance.} Remember the relationship between carbon dioxide, carbonic acid, and hydrogen ions in the blood. Changes in ventilation directly affect \(PaCO_2\), which in turn influences blood pH. \(CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + HCO_3^-\).

Answer 1

The Correct Option is A

Let's analyze each statement concerning respiratory acid-base disorders: Statement I: Respiratory Acidosis is caused by retention of carbon dioxide. The \(PaCO_2\) and \(H^+\) rise. Respiratory acidosis occurs when there is hypoventilation, leading to the retention of carbon dioxide (\(CO_2\)) in the blood. Carbon dioxide reacts with water to form carbonic acid (\(H_2CO_3\)), which then dissociates into hydrogen ions (\(H^+\)) and bicarbonate ions (\(HCO_3^-\)). The increase in \(H^+\) ions lowers the blood pH, causing acidosis. Therefore, in respiratory acidosis, the partial pressure of arterial carbon dioxide (\(PaCO_2\)) rises, and consequently, the concentration of \(H^+\) ions also rises. Statement I is correct. Statement II: In Respiratory alkalosis there is the fall in \(PaCO_2\) and \(H^+\). Respiratory alkalosis occurs when there is hyperventilation, leading to an excessive elimination of carbon dioxide (\(CO_2\)) from the blood. This decreases the concentration of carbonic acid (\(H_2CO_3\)) and subsequently the concentration of hydrogen ions (\(H^+\)), leading to an increase in blood pH (alkalosis). Therefore, in respiratory alkalosis, the partial pressure of arterial carbon dioxide (\(PaCO_2\)) falls, and consequently, the concentration of \(H^+\) ions also falls. Statement II is correct. Since both statements accurately describe the changes in \(PaCO_2\) and \(H^+\) in respiratory acidosis and alkalosis, respectively, both statements are correct.