Control of respiration

Question 1

Respiratory control center

Answer 1

Located in the medulla; generates the respiratory rhythm spontaneously but receives input from other regulators

Question 2

Carotid Peripheral Chemoreceptors

Answer 2

Located on the carotid bodies at the bifurcation of the common carotid arteries

Stimulated most strongly by decreases in arterial PO2; also sense increases in PCO2 and decreases in arterial pH

Allow rapid response to changes in CO2 and pH during sudden physical exertion; mediate ventilation changes in response to pH alterations

Question 3

Aortic Peripheral Chemoreceptors

Answer 3

Located in the aortic bodies, on the aortic arch

Stimulated by decreases in PO2 and increases in PCO2

Question 4

Central chemoreceptors

Answer 4

Located in the ventral surface of the medulla

Sensitive to PaCO2; CO2 crosses the BBB into the CSF where it combines with water and dissociates into HCO3- and protons; chemoreceptors bind the protons and stimulate breathing in response to increased CO2

Also activated during intense exercise when lactic acid is liberated, increasing the proton-mediated stimulus for ventilation