When arterial carbon dioxide rises above normal, what happens to respirations?

When arterial carbon dioxide rises above normal, what happens to respirations?

• A. Respirations decrease in rate
• B. Respirations increase in rate and depth
• C. Respirations become irregular
• D. Respirations stop

Answer: (B)

When arterial carbon dioxide rises, the body pushes ventilation higher to blow off the excess CO2. The respiratory control centers detect the lower pH in cerebrospinal fluid that results from CO2 crossing into the CSF. That chemical signal stimulates the medullary respiratory center to increase both how often you breathe (rate) and how deeply you breathe (tidal volume). The combined effect is a rise in minute ventilation, helping to restore normal CO2 levels. This is the strongest stimulus for breathing under normal conditions, more influential than oxygen levels. So the expected response is faster, deeper breathing. Slower, irregular, or stopped breathing would reflect abnormal or failing control, not the typical response to elevated CO2.

When arterial carbon dioxide rises, the body pushes ventilation higher to blow off the excess CO2. The respiratory control centers detect the lower pH in cerebrospinal fluid that results from CO2 crossing into the CSF. That chemical signal stimulates the medullary respiratory center to increase both how often you breathe (rate) and how deeply you breathe (tidal volume). The combined effect is a rise in minute ventilation, helping to restore normal CO2 levels. This is the strongest stimulus for breathing under normal conditions, more influential than oxygen levels. So the expected response is faster, deeper breathing. Slower, irregular, or stopped breathing would reflect abnormal or failing control, not the typical response to elevated CO2.