Vagus Nerve

The vagus nerve runs from the brain stem all the way through the neck and thorax, ending in the abdomen. It's the longest cranial nerve and lives up to its name which is derived from Latin meaning "wandering". It is also known as the pneumogastric nerve since it impacts both the lungs and stomach. One additional name is the cranial nerve X, as it's the tenth of twelve paired cranial nerves. The vagus nerve impacts a wide variety of functions including heart rate, gastrointestinal peristalsis, sweating, numerous muscle movements in the mouth, including speech, as well as those of the inner canal of the outer ear. It's hard to imagine one nerve doing so much.