Reflex arch and mechanisms of AspR, ExpR and CR and their voluntarycounterparts. Schematic illustration of the reflex arch and mechanismsof AspR, ExpR and CR and their voluntary counterparts. A- afferent roots: viatrigeminal nerve from the upper part of nasal cavity for sniffing, via n.glosso-pharyngicus from the nasopharynx for AspR, via n. laryngicus sup. fromthe larynx for ExpR and via n. vagus from tracheal-bronchial region andproprioceptive afferents for CR. E- efferent roots: to inspiratory muscles(diaphragm and external intercostals) and to expiratory muscles (abdominal andinternal intercostals) for ExpR and CR. C- central structures: “Generatorfor inspiration” in pre-Bötzinger complex for AspR, “generatorfor expiration” in NSRF- nucleus sub-retro-facialis for ExpR, and bothgenerators for CR. Breathing manoeuvres allow voluntary performance of allthree reflexes (voluntary sniffs, prompt expiration and sniff followed bystrong expiration), reproduced with permission from our review .