PeristalsisJejunumEsophagusManometryDeglutitionGastrointestinal MotilityIleumEsophageal Motility DisordersIntestine, SmallEsophageal Sphincter, LowerPressureUreterEsophageal AchalasiaMuscle, SmoothEsophagogastric JunctionMuscle ContractionCineradiographyGuinea PigsAirEnteric Nervous SystemRespiratory System AbnormalitiesReflex, AbdominalKidney PelvisJejunal DiseasesIntestinal MucosaIntestinal AbsorptionDuodenumDeglutition DisordersUrinary Tract Physiological PhenomenaSenna ExtractJejunal NeoplasmsColonAtropineGastroesophageal RefluxMethysergideScopolamine HydrobromideDigestive System Physiological PhenomenaIntestinesCatenanesSubmucous PlexusEsophageal Sphincter, UpperPharynxHernia, HiatalPurinergic AntagonistsFundoplicationLaryngeal NervesEsophageal DiseasesReflexBornanesBarium SulfateDigestive SystemOpossums