Word parts
What it means
The "rest and digest" half 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 , working opposite the sympathetic "fight or flight" half. Its main nerve is the vagus nerveVAY-gus nervThe 10th cranial nerve, which runs from the brain stem to the chest and belly and slows the heart and helps digestion.Full entry and its chemical messenger is acetylcholine. It slows the heart, narrows the pupils and the airways, and increases saliva, bowel movement and bladder emptying. Drugs that block it (anticholinergics) cause the opposite: dry mouth, a fast heart, constipation and trouble passing urine.
Remember it
Parasympathetic = rest and digest; sympathetic = fight or flight.
At a glance
| Spanish | sistema nervioso parasimpático |
|---|---|
| Also written | PSNS |
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.
para-
A word beginning that means beside, near, beyond or abnormal.
peripheral nervous system
All the nerves outside the brain and spinal cord, which link them to the rest of the body.
vagus nerve
The 10th cranial nerve, which runs from the brain stem to the chest and belly and slows the heart and helps digestion.