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
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
"Patients with HD have a slightly more active sympathetic nervous system, which is what drives the fight or flight response, and theoretically have more norepinephrine," Schultz explains.
From Science Daily ● Dec. 2, 2024
Imai’s team discovered that those neurons send signals to the animal’s fat stores via the sympathetic nervous system, a network of nerves carrying messages from the brain throughout the body.
From Science Magazine ● May 22, 2024
The smaller arteries all over the body are supplied with vasoconstrictor and vasodilator nerve fibers from the sympathetic nervous system.
From Arteriosclerosis and Hypertension: with Chapters on Blood Pressure, 3rd Edition. by Louis Marshall Warfield
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.
