Word parts
What it means
One of two divisions of the autonomic nervous systemaw-tuh-NOM-ik NUR-vus SIS-tumThe part of the nervous system that controls body functions without conscious thought, such as heart rate, breathing and digestion.auto- selfnom/o law, control-ic relating toFull entry . It slows the heart, narrows the pupils, increases saliva and digestion, and helps empty the bladder and bowels. Much of it runs through the vagus nerve, and its main chemical messenger is acetylcholine. The sympathetic division does the opposite, preparing the body for "fight or flight."
Remember it
Parasympathetic: rest and digest. Sympathetic: fight or flight.
Easy to confuse with
sympathetic nervous system
The branch of the autonomic nervous system that gets the body ready for stress or danger ("fight or flight").
Related terms
autonomic nervous system
The part of the nervous system that controls body functions without conscious thought, such as heart rate, breathing and digestion.
anticholinergic
A drug or effect that blocks acetylcholine, a nerve messenger, in parts of the nervous system.
acetylcholine
A chemical messenger that nerves release to signal muscles, glands and other nerves.
sympathetic nervous system
The branch of the autonomic nervous system that gets the body ready for stress or danger ("fight or flight").
vagus nerve
The 10th cranial nerve, which runs from the brain stem to the chest and belly and slows the heart and helps digestion.