Gustatory function of the soft palate.

Several characteristics of the gustatory function of the soft palate principally elucidated by our own recent investigations, as well of those of others, are described. The soft palate has a gustatory function which is independent of the tongue and is innervated by the greater petrosal nerve. Taste papillae of the soft palate are morphologically similar to the fungiforme papillae which exist on the anterior part of the tongue. In individuals aged approximately 20 years, gustatory functions of the soft palate, examined by means of the electro-gustatory and filter paper disk test's are as good as those of the tongue innervated by the chorda tympani and glossopharyngeal nerve. In younger individuals, the gustatory function of the soft palate plays as important a role as that of the tongue. Gustatory thresholds of the soft palate, as well as those of other sites innervated by other taste nerves, tend to be elevated with aging, and the degree of elevation in the soft palate is much greater than that of other sites. The most sensitively perceived taste at the soft palate is a sweet taste in the majority of subjects. Taste papillae of the palate in rats become flattened and decrease in number with age. These changes are more prominent in zinc-deficient rats.