sympathetic nervous system

noun

: the part of the autonomic nervous system that contains chiefly adrenergic fibers and tends to depress secretion, decrease the tone and contractility of smooth muscle, and increase heart rate compare parasympathetic nervous system

Examples of sympathetic nervous system in a Sentence

Recent Examples on the Web

One possible explanation, the researchers say, is that spending time in nature lowers the activity of our sympathetic nervous system, which regulates stress hormones, and taps into the parasympathetic nervous system, which promotes our calm and relaxation responses. —Andrea Petersen, WSJ, 2 Aug. 2022

In your lungs, signals from the sympathetic nervous system dilate airways and often increase your breathing rate and depth. —Arash Javanbakht, Discover Magazine, 7 Sep. 2023

Loneliness and isolation drive unbalanced activation of the sympathetic nervous system, leading to hypervigilance, or scanning the environment for threats. —Clay Marsh, Fortune Well, 15 July 2023

The sympathetic nervous system is the gas pedal that speeds up the systems involved in fight or flight. —Arash Javanbakht, Discover Magazine, 7 Sep. 2023

Dehydration also makes the sympathetic nervous system work harder, which puts stress on the body, triggering it to release hormones, like adrenaline, Dr. Pilchik says. —Erica Sweeney, Men's Health, 24 Aug. 2023

The sympathetic nervous system is part of your body's fight-or-flight response. —Cathy Cassata, Health, 29 July 2023

In other words, loneliness and isolation drive disease and shorten life spans through unbalanced activation of the sympathetic nervous system induced by the perception of threat and chronic stress. —Clay Marsh, Fortune Well, 15 July 2023

In response to a threat, lightning-fast hormonal changes activate the sympathetic nervous system. —Eleanor Morgan, refinery29.com, 13 July 2023

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Word History

First Known Use

1850, in the meaning defined above

Kids Definition

sympathetic nervous system

noun

: the part of the autonomic nervous system that is concerned especially with preparing the body to react to situations of stress or emergency, that controls expansion of the pupil of the eye and air passages, increases the heart rate, slows digestion, and narrows most blood vessels, and that is made up of nerve fibers that trigger the release of norepinephrine compare parasympathetic nervous system

Medical Definition

sympathetic nervous system

noun

: the part of the autonomic nervous system that is concerned especially with preparing the body to react to situations of stress or emergency, that contains chiefly adrenergic fibers and tends to depress secretion, decrease the tone and contractility of smooth muscle, increase heart rate, and that consists essentially of preganglionic fibers arising in the thoracic and upper lumbar parts of the spinal cord and passing through delicate white rami communicantes to ganglia located in a pair of sympathetic chains situated one on each side of the spinal column or to more peripheral ganglia or ganglionated plexuses and postganglionic fibers passing typically through gray rami communicantes to spinal nerves with which they are distributed to various end organs

called also sympathetic system

compare parasympathetic nervous system