NEURAL CONTROL OF RESPIRATORY MOVEMENTS

Publisher Summary This chapter describes neural control of respiratory movements. In both fishes and mammals, the central respiratory system generates an oscillating activity that finally leads to the alternating activation of antagonistic sets of respiratory pump muscles. In fishes, the pumping movements result in a fairly continuous flow of water through the respiratory system and over the gills. It has been shown with paralysis-, transsection- and denervation experiments that the brains of both fishes and mammals contain intrinsic oscillators that generate the respiratory rhythm. In mammals, this function is located in the pontine pneumotaxic centre that operates together with the dorsal and ventral bulbar respiratory nuclei. A second oscillator that only manifests in unanesthetized awake animals has been found in the reticular formation of the medulla. Normally, these oscillators are coupled, but when isolated, each can generate the rhythm by itself. In fishes, the medullary reticular oscillator appears to play a more dominant role although mesencephalic neurons that act on the medullary oscillator were discovered in an area of the fish brain roughly comparable to the pontine region of mammals.