We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Health

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Are the Different Parts of the Autonomic Nervous System?

By Synthia L. Rose
Updated: May 17, 2024
Views: 8,736
References
Share

Responsible for managing involuntary glands, involuntary reflexes and involuntary muscles in the body, the autonomic nervous system (ANS) is an umbrella comprised of three distinct nervous systems: the parasympathetic system, the sympathetic system, and the enteric system. All three of these nervous systems rely on special autonomic neurons that regulate essential functions by delivering signals from the brain to muscles and glands that need to operate without conscious effort. ANS nerve cells, also called motor neurons, mainly control glandular secretions, digestive system organs, heart muscles and various smooth muscles. Motor neurons often take their cue from dangers or changes in the environment, triggering the brain to release response signals.

Regulated by nerves in the spinal cord and the brain’s medulla region, the parasympathetic division of the nervous system orchestrates de-stimulation of the body. It works with digestive system organs such as the pancreas, liver and stomach as well as sensory organs such as the nose and eyes to slow the heartbeat, constrict pupils, and create a relaxed and subdued mood so that the gastrointestinal system can break down and absorb food. The effects of the parasympathetic nervous system, which also include the relaxation of the sphincter muscles, can last until food and liquids pass through the intestines and bladder for waste excretion. This part of the autonomic nervous system is often referred to as the “rest and digest” system.

Designed to stimulate the body in moments of excitement, aggression or fear, functions of the sympathetic division of the nervous system are the antithesis of the parasympathetic system. The sympathetic nervous system, controlled by neurons in the lumbar section and the thoracic section of the spinal cord, causes rapid heart rhythm, reduced digestion and elevated blood pressure. Commonly called the “flight or fight” part of the autonomic nervous system, this system relies on the release of chemicals such as norepinephrine and acetylcholine to send the body into a heightened and hyperactive state.

The enteric part of the autonomic nervous system is often called the intrinsic nervous system and exclusively caters to the digestive system where it is entirely located. Served by neurons in the membranes of the esophagus, intestines, pancreas and other gastrointestinal organs, the enteric nervous system provides assistance to digestive functions handled by the parasympathetic part of the nervous system while also providing digestive defenses for the body. Defensive digestive functions of the enteric system include triggering vomiting or diarrhea when harmful bacteria or viruses have entered the digestive tract and must be expelled. The enteric part of the autonomic nervous system also controls the amount of blood flowing to the digestive region and how abdominal muscles constrict to move food through the digestive tract.

Share
WiseGeek is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Link to Sources

Editors' Picks

Discussion Comments
Share
https://www.wisegeek.net/what-are-the-different-parts-of-the-autonomic-nervous-system.htm
Copy this link
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.