Question 8
Ryan, a patient with emphysema, experiences an increase in his blood carbon dioxide levels.
Cells in his blood vessels will pick up the increased carbon dioxide and communicate to neur
(cells) in his brain stem. The neurons then send a message to Ryan's breathing muscles to
increase his breathing rate and depth (known as hyperventilation). This will allow him to exh
more carbon dioxide, lowering his blood carbon dioxide levels back to normal.
In the example above, identify the following:
Control center:
Receptor:
Variable:
Effector:
Question 9
In negative feedback mechanisms, what is the pathway between the control center and the
effector called?
2