Circumvallate papillae of tongue are supplied by which nerve?
**Core Concept**
The **tongue** has various types of papillae, including circumvallate papillae, which are involved in the sensation of **taste**. The **nervous supply** to these papillae is crucial for the transmission of taste sensations. The **glossopharyngeal nerve** is one of the cranial nerves responsible for **swallowing** and **taste**.
**Why the Correct Answer is Right**
The **glossopharyngeal nerve (IX)** is responsible for the sensory innervation of the **circumvallate papillae**, which are located at the base of the tongue. This nerve transmits **taste sensations** from the posterior one-third of the tongue, including the circumvallate papillae, to the **brain**. The **taste buds** on the circumvallate papillae contain **receptor cells** that respond to different **taste modalities**.
**Why Each Wrong Option is Incorrect**
**Option A:** The **facial nerve (VII)** is responsible for taste sensation from the anterior two-thirds of the tongue, not the posterior one-third.
**Option B:** The **hypoglossal nerve (XII)** is a motor nerve that supplies the muscles of the tongue, not involved in taste sensation.
**Option D:** The **vagus nerve (X)** is involved in various functions, including swallowing and sensation from the pharynx, but not specifically taste from the circumvallate papillae.
**Clinical Pearl / High-Yield Fact**
Remember that the **glossopharyngeal nerve** is responsible for the **gag reflex** and **swallowing**, in addition to **taste** sensation from the posterior tongue.
**Correct Answer:** Correct Answer: C. Glossopharyngeal nerve.