Circum vallate papilla is supplied by
(A) (Glossopharyngeal nerve) (270-BDC-3 6th (626- Snell 9th)CIRCUM VALLATE PAPILLAE- are situated on the mucous membrane just anterior to the sulcus terminalus, and that their taste buds are innervated by the Ninth cranial nerve (Glossopharyingeal). It is presumed that during development the mucous membrane of he posterior third of the tongue becomes pulled anteriorly slightly, so that fibres of the ninth cranial nerve cross the succus terminals to supply these taste buds* Filiform papillae or conical papillae- they aee smallest and most numerous of he lingual papillaeTASTE PATHWAY* The taste from anterior two third of tongue except from vallate papillae is carried by chorda tympani branch of facial till the geniculate ganglion the central processes go to tractus solitarius in the medulla* The taste from posterior one third of tongue including the circumvallate papilae is carried by cranial nerve IX till the inferior ganglion. The central processes also reach the tractus solitarius* Taste from posterior most part of tongue and epiglottis travels through vagus nerve till the inferior ganglion of vagus these control processes also reach tractus solitarius* After a relay in tractus solitarius the solitary thalamic tract is formed which becomes a part of trigeminal lemniscus and reaches postero-ventro medial nucleus of thalamus of the opposite side** Area of Taste- lowest part of post central gyrusComparison of the parts of the tongue Anterior two- thirdsPosterior one - thirdPosterior most part valleculaSituationLies in mouth cavityOropharynxOropharynxStructureContains papillaeContains lymphoid tissue FunctionChewingDeglutitionDeglutitionSensory nerveLingual (post-trematic branch of 1st erch)GlossopharyngealInternal laryngeal branch of vagusSensation of tasteChorda tympani except circum-vallate papillae (pre-trematic branch of 2nd arch)Glossopharyngeal including the vallate papillaeInternal laryngeal branch of vagusDevelopment of epithelium from endodermLingual swellings of larchTuberculum impar which soon disappearsThird arch which forms large ventral part of hypobranchial eminenceFourth arch which forms small dorsal part of hypobranchial eminence* Receptors for Taste sensation are the type 3 cells of Taste buds* Third order neuron are in the posteroventral nucleus of the thalamus the axons from the third neuron project into the parietal lobe of the cerebral cortex* Taste centre in the opercular insular cortex ie in lower parts of post central gyrus
Glossopharyngeal nerve
Lingual nerve
Hypoglossal nerve
Facial nerve
Head & Neck