ATI Pathophysiology Practice Exam

What does the respiratory system eliminate when there is an excess of hydrogen ions in the body?

1. Oxygen

2. Nitrogen

3. Carbon dioxide

4. Water vapor

The correct answer is: Carbon dioxide

When there is an excess of hydrogen ions in the body, the respiratory system plays a crucial role in maintaining acid-base balance by eliminating carbon dioxide. The presence of excess hydrogen ions indicates a state of acidosis, which can occur due to various conditions, including metabolic disorders or respiratory insufficiency. To counteract this acidosis, the body increases the depth and rate of respiration, which promotes the exhalation of carbon dioxide. As carbon dioxide levels decrease, the concentration of hydrogen ions in the blood also decreases, helping to restore a more neutral pH balance. This regulatory mechanism is vital for homeostasis. In this context, oxygen, nitrogen, and water vapor are not directly related to the body’s response to excess hydrogen ions. Oxygen is primarily involved in the process of cellular respiration and is not eliminated in response to changes in hydrogen ion concentrations. Nitrogen is a largely inert gas in the respiratory process and does not play a role in acid-base balance. Water vapor is produced during respiration but does not serve a significant role in correcting hydrogen ion levels. Thus, eliminating carbon dioxide effectively helps to manage acid-base disturbances in the body.