The overdrive mechanism observed during hyperventilation is due to
The ventral respiratory group contributes to the extra respiratory drive (overdrive mechanism) During quiet breathing: Expiration is a passive process and the neurons from the ventral respiratory group remain almost totally inactive during quiet respiration. Unlike the dorsal respiratory group (DRG; dorsal group of neurons), VRG (the ventral group of neurons) doesnot appear to paicipate in the basic rhythmic oscillations that control respiration. Extra-respiratory drive(overdrive mechanism) : When the reapiratory drive for increased pulmonary ventilation becomes greater than normal, for example, during exercise, respiratory signals spill over to VRG from DRG. So, VRG contributes to the extra respiratory drive (overdrive mechanism). The neurons of VRG contribute to both inspiration and expiration; especially, they are impoant in providing powerful expiratory signals to the abdominal muscles during very heavy expiration. Dorsal Respiratory group Ventral Respiratory group Location Nucleus Tractus Solitarius in medulla Nucleus Retro Ambigualis in medulla Function Inspiratory ramp signals- stimulates inspiration Inactive during quiet breathing; Active during forced expiration. Ref: Ganong&;s Review of Medical Physiology 26th edition Pgno: 645-657
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Respiratory system