A nerve that supplies nerve fibers to the pharynx (throat), larynx (voice box), trachea (windpipe), lungs, heart, esophagus (passage from the mouth to the stomach), and the intestinal tract; as far as the transverse part of the colon: The vagus nerve emerges from the medulla oblongata (part of the brain stem) and it is classified as a cranial nerve because it comes from that brain stem.

The vagus nerve transmits sensory information back to the brain from major organs in the body; including the ears, the tongue, the pharynx, the larynx, and much of the digestive system.

A complete interruption of the vagus nerve causes a condition in which the voice is hoarse and nasal, and the vocal cord on the affected side is immobile; resulting in difficulty in swallowing (dysphagia) and speaking (dysphonia).

The vagus nerve also stimulates the production of stomach acid and pancreatic juice; stimulates the activity of the gallbladder, and increases the rhythmic muscular contractions that move food through the digestive tract.