nervous system
Americannoun
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the system of nerves and nerve centers in an animal or human, including the brain, spinal cord, nerves, and ganglia.
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a particular part of this system.
noun
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The system of neurons and tissues that regulates the actions and responses of vertebrates and many invertebrates. The nervous system of vertebrates is a complex information-processing system that consists mainly of the brain, spinal cord, and peripheral and autonomic nerves. It receives chemical information from hormones in the circulating blood and can also regulate secretions of the endocrine system by the action of neurohormones. The nervous systems of invertebrates vary from a simple network of nerves to a complex nerve network under the control of a primitive brain.
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See also autonomic nervous system central nervous system peripheral nervous system
Other Word Forms
Noun Inflected Forms
Etymology
Origin of nervous system
First recorded in 1730–40
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.
Parkinson's is a progressive disorder that affects the brain, nervous system, and muscle control.
From BBC ● Jul. 27, 2026
Tau is normally found throughout the brain and nervous system, where it helps maintain the structure of neurons and the networks they form.
From Science Daily ● Jul. 20, 2026
“Your nervous system isn’t asking for perfection,” the caption read.
From The Wall Street Journal ● Jul. 19, 2026
Cells lining blood vessels in the brain contain a transporter called GLUT1 that normally carries glucose into the central nervous system.
From Science Daily ● Jul. 17, 2026
In Germany, the effects of Marburg virus on the brain were particularly frightening, and resembled the effects of rabies: the virus somehow damaged the central nervous system and could destroy the brain, as does rabies.
From "The Hot Zone" by Richard Preston
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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.