Chemical Control of Respiration Central Chemoreceptors Peripheral Chemoreceptors

Stimulation of inspiratory area by the signals from the chemosensitive area

Location of the peripheral Chemoreceptors

Effect of Increased arterial Pco2 on ventilation Brain ECF Pco2 (When arterial CO2 + H2O Pco2 Brain ECF >70 – 80 H2CO3 mm Hg) H + HCO3 Brain ECF H Weakly+ Medullary Peripheral Respiratory Central Chemoreceptors Center Chemoreceptors Ventilation Arterial PCO2 ( ) Ca + + +

Peripheral Chemoreceptors Situated in aortic and carotid bodies Respond to Decreases in arterial PO2 Increases in arterial PCO2 Decreases in arterial pH

Effect of threateningly low arterial Po2 on ventilation Arterial Po2 < 60 mm Hg Emergency Life-Saving mechanism Peripheral Medullary Central Chemoreceptors Respiratory Chemoreceptors Center Ventilation Arterial Po2 Relieves + - - No effect on +