Controls of Breathing Page 35

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

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

Pons Smooths out transition between inspiration and expiration

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

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

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

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