1. Controls of Breathing
Page 35

2. What controls breathing?
Involuntary/passive
Respiratory center- group of neurons in the brain stem which control inspiration and expiration
Controls breathing rate and depth

3. How does the brain control respiration?
Parts of the Brain:
Medulla oblongata-
Inspiration center-
Expiration center-
Basic rhythm pattern of diaphragm
Pons-

4. Pons
Smooths out transition between inspiration and expiration

5. How are CO2 levels detected in the blood?
Chemoreceptors-
AKA-chemosensitive areas
Medulla chemoreceptors-
Sensitive to concentration changes of CO2, and pH
Too much CO2 - breathing increases to rid body of excess CO2

6. How are O2 levels detected in the blood?
Peripheral chemoreceptors-
Sensitive to low concentration of O2
Triggers the respiratory center to increase breathing rate

7. Emotions- fear and pain can increase breathing rates
If breathing is stopped, CO2 and H+ build up and O2 gets lower- body will have urge to breathe
Effects of hyperventilation- too much of an increase in breathing rate- can be dizzy or faint due to low CO2 levels, cerebral blood vessels constrict
Can be averted by breathing in paper bag which has a higher conc. Of CO2

8. Effects of hypoventilation-
can be dizzy or faint due to low O2 levels, can cause death if rate is slowed too much
Typically caused by mountain sickness or intake of sedatives, stroke