sympathetic nervous system

IPA/sɪm.pəˌθet.ɪk ˈnɜː.vəs ˌsɪs.təm/
IPA/sɪm.pəˌθet̬.ɪk ˈnɝː.vəs ˌsɪs.təm/

sympathetic nervous system — noun

1. The part of your body's automatic nervous wiring that gets you ready for action

1.nounB2
Definition

The part of your body's automatic nervous wiring that gets you ready for action when you face danger or stress — speeding up your heart, opening your airways wider, and sending extra blood to your muscles. It is often called the 'fight-or-flight' system.

Example

Jenna heard footsteps behind her, and her sympathetic nervous system made her heart pound.

triggered by perceived danger

Kenji's biology book said the sympathetic nervous system helps the body react in an emergency.

definition in context

Common collocations
  • sympathetic nervous system activates
  • sympathetic nervous system responds
  • sympathetic nervous system kicks in
  • calm the sympathetic nervous system
  • stimulate the sympathetic nervous system
  • sympathetic nervous system activity
Antonyms

Grammar Patterns

the sympathetic nervous system

Usage Note

The sympathetic nervous system works automatically — you cannot control it by will. It is one of two branches of the autonomic nervous system; the other is the parasympathetic nervous system, which controls rest and digestion. In everyday English, people often describe its effects as an 'adrenaline rush.'

Common Mistakes

I need to turn on my sympathetic nervous system before the exam.
My sympathetic nervous system activated automatically before the exam.
The SNS is involuntary; you cannot switch it on or off by choice.
The sympathetic nervous system only works when you are scared.
The sympathetic nervous system also activates during exercise, excitement, or any situation that demands alertness.
It responds to any kind of stress or high-arousal state, not just fear.

Word family

Synonym discussion

Sense: noun/1

The autonomic nervous system (ANS) is the broad network that controls automatic body functions such as heartbeat and digestion. The sympathetic nervous system is one half of the ANS, responsible for the 'fight-or-flight' response that readies the body for action. Its counterpart, the parasympathetic nervous system, does the opposite — it calms the body down and manages 'rest and digest' activities. While the ANS is the umbrella term for the whole automatic system, the sympathetic branch specifically handles high-arousal states. For example, when a car horn suddenly blares behind you, it is your sympathetic nervous system — not the entire ANS — that makes you jump and your heart race.

autonomic nervous system ↗parasympathetic nervous system ↗fight-or-flight response

Common collocations

Nouns

  • activation of
  • response of
  • activity of
  • stimulation of
  • overactivity of

Adverbs

Phrases

  • sympathetic nervous system response
  • sympathetic nervous system activity

Prepositions

  • of the sympathetic nervous system

Etymology

GreekLatinFrenchEnglish

The word 'sympathetic' comes from the Greek sympatheia, meaning 'fellow feeling' or 'acting together.' Ancient Greek physicians, especially Galen, used the idea of 'sympathy' between body parts to describe how one organ could affect another at a distance. In the 1700s and 1800s, anatomists applied this term to the chain of nerves that connected various internal organs and seemed to make them 'feel together' — hence, the sympathetic nervous system. The modern understanding of its role in the fight-or-flight response developed in the early 20th century.

First known use

1850

1850, in the meaning defined above