ABSTRACT
Nausea and vomiting are controlled by the vomiting center in the medulla;21 (this chapter provides references to many ofthe primary sources for the pathophysiology of emesis), Input to the vomiting center comes from several sources. The vagus and sympathetic nerves from the gastrointestinal tract may stimulate vomiting. The vestibular apparatus sends impulses via the cerebellum. (This source is important in nausea related to inner ear disorders as well as in motion sickness.) Cortical sources are also presumably involved. Much of the emetogenicity of cancer chemotherapy appears to be related to effects on the chemoreceptor trigger zone (CTZ), an area on the upper surface of the medulla from which neurons pass into the vomiting center.
