sympathetic nervous system

American  

noun

1. Anatomy. the part of the autonomic nervous system consisting of nerves that arise from the thoracic and lumbar regions of the spinal cord, functioning in opposition to the parasympathetic nervous system, and producing effects such as increasing the heart rate and dilating the pupils.

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sympathetic nervous system Scientific  

/ sĭm′pə-thĕt′ĭk /

1. 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.

2. Compare parasympathetic nervous system

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Example Sentences

"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

Much, very much, is still to be learned concerning the sympathetic nervous system, and all such increase in knowledge can come in one way only, clinical observation of Osteopathic treatment.

From Philosophy of Osteopathy by Still, A. T. (Andrew Taylor)