During exercise, which system increases breathing rate to meet oxygen demand?

• A. Respiratory System
• B. Skeletal System
• C. Endocrine System
• D. Integumentary System

Answer: (A)

When you exercise, your tissues need more oxygen and produce more carbon dioxide, so your breathing rate increases to bring in more O2 and remove CO2. This rapid adjustment is carried out by the respiratory system. The brainstem’s respiratory centers respond to chemical signals from chemoreceptors that monitor blood CO2 and O2 levels, along with input from the body about how hard you’re exercising. In response, they send stronger signals to the diaphragm and intercostal muscles, increasing both the rate and depth of breaths.

The other systems aren’t directly responsible for changing breathing rate. The skeletal system provides the bones and the muscles that move the chest wall, but it doesn’t regulate how fast you breathe. The endocrine system can influence overall arousal and metabolism, but the immediate control of breathing rate comes from the respiratory system. The integumentary system mainly handles temperature regulation and protection of the body, not the regulation of ventilation.