What sensory functions does the glossopharyngeal nerve (CN9) provide?

The glossopharyngeal nerve, also known as cranial nerve IX, is primarily responsible for providing sensory functions from specific regions of the body. Among its key roles, this nerve facilitates sensation from the posterior one-third of the tongue, which includes taste sensation as well as general sense, such as touch, pain, and temperature. Additionally, it innervates the pharynx and contributes to the sensation of the carotid body and sinus, which are involved in regulating blood pressure and respiratory functions.

This specialization in sensory functions makes the glossopharyngeal nerve critical for both the perception of taste and the initiation of the swallowing reflex, as it receives signals related to the food and liquids entering the throat. Understanding the scope of its sensory responsibilities helps clarify its importance in both gustatory and physiological responses in the throat and tongue, which is why the identification of its role in providing sensation from the posterior tongue and pharynx stands as the correct understanding of the nerve's functions.