Vagus Nerve

Also known as cranial nerve X, it is primary nerve of the parasympathetic nervous system that reduces heart rate, blood pressure, sweating and stimulates digestion. It also controls some mouth movements.

Reference:
Bear, M.F., Connors, B.W. & Paradiso, M.A. (2001). Neuroscience: Exploring the Brain. (2nd Edition). Baltimore, MD: Lippincott Williams & Wilkins.