 You are hyperventilating – reducing the amount of carbon dioxide in your body.  The result/stimulus is your blood is becoming too alkaline – your pH is too high.

 Set point  Sensors  Controller  Effector

 Set point – near 7 ( )  Sensors – nerve receptor cells in arteries  Controller – brain  Effector – muscles in chest (intercostals and diagphragm)  Response – if pH is high (alkaline) then slow breathing if pH is low (acid) then speed breathing

 Nervous system – brain (controller)  Circulatory system – blood and arteries (sensor)  Muscle system – rib muscles and diaphragm (effectors)  Respiratory system – lungs (effectors)

You are breathing too fast which is causing your carbon dioxide levels to drop which is raising your blood pH. As your body leaves homeostasis a negative feedback system kicks in. Your body senses this through the receptors in your arteries (circulatory system) which then signal the controller in your brain (nervous system). The controller detects that the pH level is above the set point and needs to return your body to homeostasis. (continued)

To return your body to homeostasis and bring your blood pH level back to the set point, your brain signals the effectors. The effectors are the muscles (muscle system) around your lungs (respiratory system) which help you breathe. The effectors are signaled to decrease your breathing rate and allow the carbon dioxide levels in your blood to rise, thus lowering your blood pH and returning you to homeostasis.