Vagus nerve

The vagus nerve (/ˈveɪɡəs/ VAY-gəs), historically cited as the pneumogastric nerve, is the tenth cranial nerve or CN X, and interfaces with parasympathetic control of the heart and digestive tract. The vagus nerves are paired; however, they are normally referred to in the singular. It is the longest nerve of the autonomic nervous system in the human body.