GLOSSARY

The vagus nerve (CN X) is the tenth and longest cranial nerve, emerging from the medulla and extending through the neck and chest to the abdomen; it carries about 75 percent of the body’s parasympathetic fibres.

Functions

• Heart: slows the heart rate (via the sinoatrial node).
• Lungs: airway narrowing and mucus secretion.
• Digestive tract: increases gut motility and digestive secretions as far as about the first third of the transverse colon.
• Larynx and pharynx: voice (the recurrent laryngeal nerve) and swallowing.
• Sensory: about 80 percent of vagal fibres are sensory (afferent), carrying information from the viscera (such as satiety, blood pressure, and inflammation) to the brain.

Characteristics