The Parasympathetic Nervous System

Marketing Dept., | 6 min read
Marketing Dept., | 6 min read

The parasympathetic nervous system (PNS) is a key part of our autonomic nervous system, responsible for regulating many of the body's involuntary functions. It is often referred to as the "rest and digest" system, as it helps the body conserve energy and perform essential maintenance activities. In this blog post, we will explore the role of the PNS in maintaining bodily functions, using the content from the JoVE article "The Parasympathetic Nervous System" as a reference.

What is the Parasympathetic Nervous System?

The parasympathetic nervous system is one of the two main divisions of the autonomic nervous system, the other being the sympathetic nervous system (SNS). While the SNS is responsible for the "fight or flight" response, the PNS is responsible for "rest and digest" activities. It helps to restore the body to a state of calm and promotes regular, day-to-day bodily functions.

Activation of the Parasympathetic Nervous System

The PNS is primarily activated during restful periods when the body is relaxed. The main nerve involved in this system is the vagus nerve, which extends from the brain to various organs in the body. When the PNS is activated, it triggers several physiological responses, including:

  1. Decreased Heart Rate: The heart rate slows down, reducing the amount of energy the body uses and promoting relaxation.
  2. Increased Digestive Activity: Digestive processes are enhanced, allowing the body to efficiently process food and absorb nutrients.
  3. Constriction of the Pupils: The pupils constrict to limit the amount of light entering the eyes, which is suitable for close-up vision.
  4. Stimulation of Saliva Production: Saliva production increases, aiding in the digestion of food.

Impact on the Body

The PNS helps to counterbalance the effects of the SNS, ensuring that the body can rest, digest food, and carry out maintenance functions. This balance between the PNS and SNS is crucial for overall health and well-being. If the PNS is not functioning properly, it can lead to issues such as poor digestion, high blood pressure, and chronic stress.

The parasympathetic nervous system plays a vital role in maintaining homeostasis, the body's state of balance. It allows the body to recover from stressful situations and supports growth, repair, and energy conservation. By understanding the PNS and how it works, we can better appreciate the importance of relaxation and stress management in our daily lives.


The parasympathetic nervous system is an essential part of our physiology that helps us relax, digest food, and maintain overall health. Understanding how this system works can help us better manage stress and promote a balanced lifestyle. For a more detailed look at this topic, I recommend watching the video “The Parasympathetic Nervous System” from JoVE, which offers an in-depth and visual explanation of the role of the PNS.

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