Sometimes, during stress or trauma, a person can start to hyperventilate. Then the person might breathe into a paper bag to avoid fainting. (10.8) b. How does breathing into a paper bag help return blood pH to normal?

Verified step by step guidance

1. Understand that hyperventilation causes a decrease in carbon dioxide (CO2) levels in the blood, leading to a condition called respiratory alkalosis, where the blood pH becomes too high (more basic).
2. Recognize that CO2 is an acidic component in the blood, as it reacts with water to form carbonic acid (H2CO3), which can dissociate into hydrogen ions (H+) and bicarbonate ions (HCO3-).
3. Breathing into a paper bag causes the person to rebreathe exhaled CO2, increasing the CO2 concentration in the blood.
4. As CO2 levels rise, the reaction CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3- shifts to the right, increasing the concentration of H+ ions, which helps lower the blood pH back to normal.
5. This process helps counteract the effects of respiratory alkalosis, stabilizing the blood pH and preventing fainting.

Key Concepts

Hyperventilation

Hyperventilation occurs when a person breathes rapidly and deeply, leading to an excessive loss of carbon dioxide (CO2) from the blood. This can result in respiratory alkalosis, where the blood pH rises above normal levels, causing symptoms like dizziness and fainting. Understanding this process is crucial for grasping why interventions like breathing into a paper bag are used.

Carbon Dioxide and Blood pH

Carbon dioxide plays a vital role in regulating blood pH. When CO2 levels drop due to hyperventilation, the blood becomes more alkaline (higher pH). Breathing into a paper bag allows the person to re-inhale CO2, which helps to restore the balance and bring the blood pH back to normal levels, alleviating symptoms of hyperventilation.

Acid-Base Balance

The acid-base balance in the body is maintained through various physiological mechanisms, including respiration and metabolism. A normal blood pH is essential for proper cellular function. Interventions like breathing into a paper bag are aimed at correcting disturbances in this balance, particularly during episodes of hyperventilation, by increasing CO2 levels and thus lowering pH back to a normal range.