The tenth cranial nerve, the vagus nerve is the only cranial nerve that leaves the confines of the skull and meanders throughout the body. The word vagus, derived from the latin word vagrant, or wanderer, wanders throughout the body.
That's why we feel it in our stomach when we are upset emotionally. The vagus innervates the stomach, the gut, the liver, the heart also. Emotion begins in the mind, and is transferred to the body via the many branches of cranial nerve X, the vagus.