The chemoreceptor trigger zone (CTZ): * 1 point is responsible for the coordination of the sequence of motor events associated with emesis, without the function of the vomiting center upon stimulation, directly gives rise to impulses which generate anti-peristaltic waves in the upper gastrointestinal tract. refers to the diffuse distribution of intestinal receptors which respond to orally administered chemical emetics. is not required for effecting vomiting in response to psychogenic influences.