Question

does the tongue only have chemoreceptors?

Answer 1

No. The tongue has both the chemoreceptors and the mechanoreceptors. The chemoreceptors are the taste buds that are activated by different chemical structures of differentnature, individually and in combination providing the sensation of taste. These chemoreceptors are called the taste receptors and respond in CO-ordination to provide five basic types of taste. Other than this are located the mechanoreceptors on the mucosa of the tongue. These mechanoreceptors are of low sensitivity but respond sufficiently well to touch, temperature and pain. Consider having hot foods, how do the Oral cavity define that the food is hot and varies in intensity of temperature. It is the combined effect of the mechanoreceptors located in the oral mucosa including the tongue which is supplied by sensory parts of cranial nerves.