How Does the Body "Know" to Increase Heart and Breathing

question 47

Multiple Choice

How does the body "know" to increase heart and breathing rates when you are active?

• A) Carbonic acid is produced by decreasing oxygen levels in the blood, and when the brain sensors sense the lower pH, increased rates are triggered.
• B) Carbonic acid is produced when carbon dioxide dissolves in the blood, and when the brain sensors sense the lower pH, increased rates are triggered.
• C) When the brain senses increased fatigue in an area of the body, it triggers increased rates.
• D) The increased activity just naturally results in increased rates because the two things are correlated.
• E) The hypothalamus senses low oxygen levels as blood passes through sensors there, and increased rates are triggered.