Intro | Facial Nerve | Glossopharyngeal Nerve | Gustatory Nucleus | Papilla | Primary Gustatory Cortex | Secondary Gustatory Cortex | Taste Buds | Tongue | Vagus Nerve | Ventral Posterior Nucleus
Part 1: Image-Mapped Tutorial
Part 2: Matching Self-Test
Part 3: Multiple-Choice Self-Test
The Facial Nerve (CN VII) transmits encoded taste information away from the anterior two-thirds of the tongue in a branch called the chorda tympani. Since this cranial nerve passes through the middle ear on its way to the brain, it is sometimes damaged along with conditions affecting the ear. Middle ear damage is the most common cause of the rare condition, ageusia, or taste loss, because it tends to damage the chorda tympani of the facial nerve as well. The majority of axons in the facial nerve are each responsive to more than one taste quality, although each does tend to show a preference for one taste quality. Many facial nerve neurons also show sensitivity to temperature changes.
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The sensory portion of the VIIth cranial nerve arises from the taste buds on the anterior two-thirds of the tongue (Parent, 1996). These fibers pass through the stylomastoidi foramen (the opening or passage at the styloid and mastoid processes of the temporal bone) and synapse in the geniculate nucleus in the pons. These sensory fibers convey information about taste and proprioception.
| Reference |
Parent, A. (1996). Carpenter's human neuroanatomy (9th ed.). London: Williams & Wilkins.