sympathetic nervous system
Americannoun
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The part of the autonomic nervous system that tends to act in opposition to the parasympathetic nervous system, as by speeding up the heartbeat and causing contraction of the blood vessels. It regulates the function of the sweat glands and stimulates the secretion of glucose in the liver. The sympathetic nervous system is activated especially under conditions of stress.
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Compare parasympathetic nervous system
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"In one experiment, we use a neurotoxin to disable the sympathetic nervous system," Nigri says.
From Science Daily ● Feb. 15, 2026
It did this by boosting the activity of the sympathetic nervous system and stimulating thermogenesis in adipose tissue, leading the tissue to consume more energy in the form of heat.
From Science Daily ● Dec. 6, 2025
A cold plunge can even result in a brief euphoric feeling as your body switches from the parasympathetic to sympathetic nervous system.
From The Wall Street Journal ● Nov. 7, 2025
When the body hyperventilates, the sympathetic nervous system is activated, triggering the body’s “fight or flight” response.
From Salon ● Apr. 23, 2025
Depression and emotion may so effect the sympathetic nervous system as to cause a lowered circulatory activity.
From Applied Psychology for Nurses by Porter, Mary F.
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
