RESPIRATORY CONTROL CENTERS



The neurons controlling respiration are located at several levels in the brain stem. The most im­portant network resides in the medulla oblongata, where respiratory rhythm originates. The pons contains an apneustic center, uninhibited activity of which results in sustained inspiratory spasm (apneusis) and a pneumotactic center, which reg­ulates respiratory timing, thus determining the relative duration of inspiration and expiration. While these brain stem centers are responsible for the automatic control of ventilation, the cerebral cortex can override them during wakefulness to permit speech and other actions requiring vol­untary control of ventilation.