Final answer:
Charlie's body will respond to his breath-holding and rising carbon dioxide levels by increasing his breathing rate to normalize the levels of carbon dioxide and maintain pH balance, thus ensuring the cells' survival and proper function.
Step-by-step explanation:
When five-year-old Charlie holds his breath and his carbon dioxide levels rise, his respiratory system will respond to the situation. The body's primary drive to breathe is triggered by an accumulation of carbon dioxide, not a lack of oxygen. In response to high carbon dioxide levels, cells in the brain that monitor blood gases will trigger an increase in the breathing rate through the autonomic nervous system. This results in faster breathing, which helps to lower the carbon dioxide levels and maintain homeostasis in blood gases and pH.
The process of gas exchange occurs in the lungs, where blood changes levels of carbon dioxide and oxygen. The circulatory system then transports these gases throughout the body. If Charlie continues to hold his breath, his urge to breathe will become overwhelming due to the autonomic response to high levels of carbon dioxide, ensuring that his breathing resumes and normalizing the blood's pH level.
In essence, Charlie's respiratory system, along with his nervous and cardiovascular systems, will work together to regulate his blood gases—primarily carbon dioxide levels—and maintain a balanced pH. This is vital for the survival of cells and the proper functioning of the organism.