What Is the Nervous System? Parts, Functions, and Why It’s Important

What is the Nervous System?

The nervous system is the body’s command center and consists of the brain, spinal cord, and nerves. It is broken down into two distinct systems: the central nervous system and the peripheral nervous system. The peripheral nervous system can be further divided into the somatic nervous system (voluntary) and the autonomic nervous system (involuntary). The autonomic nervous system regulates bodily processes we cannot consciously control, including heart rate, breathing, body temperature, and digestion. Because this portion of the nervous system controls our involuntary and vital functions, it is designed to respond quickly to environmental changes, ensuring the body can adapt as needed. There are three main divisions of the autonomic nervous system, each of which plays a vital role within the body.

Sympathetic Nervous System

The sympathetic nervous system is the branch of the autonomic nervous system responsible for responding to threats and mobilizing the body into action. It is responsible for initiating movement so we can respond to threats or triggers, activating the ‘fight or flight‘ response and essentially putting the body into survival mode. When our sympathetic nervous system is activated, the adrenal glands are signaled to secrete epinephrine (adrenaline), which directs energy and vital resources within the body to be diverted to vital organs (muscles, heart, brain) so that you can focus on the task (or emergency) in front of you to ensure that you can survive the situation at hand. 

If you think about driving a car, the sympathetic nervous system is the gas pedal – it increases heart rate, stops the digestive process so energy can be used for survival purposes, and dilates airways so that more air can be delivered to tissues.

Parasympathetic Nervous System

The parasympathetic nervous system is the branch responsible for calming the body. This can happen after stressful events or in emergent situations when the sympathetic nervous system is activated. In contrast to the ‘fight or flight’ response of the sympathetic nervous system, the parasympathetic nervous system is associated with the ‘rest and digest’ state and essentially works to ‘undo’ what the sympathetic nervous system has done. Thinking back to our car analogy, the parasympathetic nervous system is the brake pedal. When we are in a parasympathetic state, we may notice our saliva and hunger signals increasing, our breathing slowing and becoming gentler, and our heart rate returning to our normal resting rate. During this time, we can relax, sleep, digest our food, and excrete waste because we are existing in a space that feels safe and is not threatened.

Enteric Nervous System

The enteric nervous system is an extensive network of neurons that is located within the walls of the gastrointestinal tract. The enteric nervous system releases neurotransmitters to support all functions of the GI tract (sensory, secretory, absorptive, motor). This system also helps manage our nutrient intake, ensures that food and stool move through our intestines properly, and keeps our blood flowing to our organs as it should. It also supports and regulates our immune defense systems in the gut, helping ensure we can combat pathogens effectively.

Supporting a Healthy Nervous System

As you can see, the nervous system plays a vital role in our daily lives, and it is essential that we support it as much as possible to ensure optimal functioning. Here are a few easy ways to support your nervous system on a daily basis:

Breathwork – Deep breathing or diaphragmatic breathing is often utilized in meditation and mindfulness to help downregulate the nervous system. By taking slow, deep breaths, we stimulate the vagus nerve and signal the central nervous system to activate the parasympathetic nervous system, the ‘rest and digest’ branch. Research has shown that mindful breathing can help reduce anxiety, alter brain waves, and even promote cognitive function and memory.

Vagus Nerve Exercises – Humming, gargling, chanting, laughing, and singing are all easy actions you can incorporate into your daily routine to stimulate the vagus nerve and activate the parasympathetic nervous system, helping you feel calmer. 

Cold Water Exposure – Cold water therapy is a great way to help support the nervous system and can be especially helpful if someone needs to calm down quickly. You can splash cold water on your face, dip your hands in cold water, or place a cold compress on your face for 15-30 seconds. This cold water activates the diving reflex, which helps ‘override’ the body’s fight-or-flight mode by slowing the heart rate, redirecting blood to vital organs, and helping you feel calmer and more present.

Herbs – read on for 5 Herbs to Support Your Stress Response & Nervous System

These are just a few ways to support a healthy nervous system, but there are many more! If you are looking for more information on supporting a healthy nervous system, or want to learn more about what the nervous system is, you can visit our online classes for additional information! 

Take 10% off any one of our Nervous System Classes with this code!: blognervoussystem10

Nervous System Session 1: A Deep Dive into the Anatomy

Nervous System Session 2: Nervous System Disorders

Nervous System Session 3: How To Support The Nervous System

References:

• Murtazina A, Adameyko I. The peripheral nervous system. Development. 2023;150(9):dev201164. doi:10.1242/dev.201164
• InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. In brief: How does the nervous system work? [Updated 2023 May 4]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279390/
• Lee SH, Park DS, Song CH. The Effect of Deep and Slow Breathing on Retention and Cognitive Function in the Elderly Population. Healthcare (Basel). 2023;11(6):896. Published 2023 Mar 20. doi:10.3390/healthcare11060896