Fig. 3.
Effects of respiratory arousal on upper airway dilator and respiratory pump muscles. Respiratory arousal is composed of three primary inputs: central respiratory pattern generator processing peripheral and central chemoreceptor afferents, reflex responsiveness to the magnitude of negative pressure in the airway generated by the respiratory pump muscles, and strength of the “wakefulness” drive. Inhibitory modulators are shown: anesthetics, opioids, and impaired consciousness of endogenous etiology. Blue arrows: excitatory; Red arrows: inhibitory; MNs = motor neurons.