PHSI 208 Lecture Notes - Lecture 7: Peripheral Chemoreceptors, Central Chemoreceptors, Carotid Body
Document Summary
During inspiration, the activity of inspiratory neurons increases steadily, apparently through a positive feedback mechanism. At the end of inspiration, the activity shuts off abruptly and expiration takes place through the recoil of elastic lung tissue. This is believed to be initiated by a pacemaker cell from the pre-botzinger complex. The positive feedback loop recruits more neurons, ( ramping ) and more inspiratory muscles. Peripheral chemoreceptors on the aortic and carotid bodies sense changes in arterial po2, pco2 and ph and adjust ventilation accordingly. Glomus cells are the carotid body oxygen sensors, and they release a neurotransmitter when. It takes a large drop in arterial po2 to trigger peripheral chemoreceptors. Glomus cells can also respond to increases in h+ (decreases in ph). They provide continuous input to the respiratory control centre. From what we know, they respond mainly to changes in pco2.
