Difference Between Sympathetic and Parasympathetic Nervous System

The key difference between sympathetic and parasympathetic nervous system is that the sympathetic nervous system is responsible for controlling the body’s responses to perceived harm and the mobilizing the “fight or flight” response while the parasympathetic nervous system is responsible for controlling the homeostasis and the body’s “rest-and-digest” response.

The autonomic nervous system is a self-controlled system that comes under the peripheral nervous system. Therefore, it basically regulates the internal environment of the body by exchanging commands between the peripheral nervous system and organs in order to maintain important bodily functions. Further, there are two main divisions in the autonomic nervous system. They are; sympathetic nervous system and parasympathetic nervous system. Both systems usually act on the same organ and generate the same action potentials, yet their functions are different and oppose to each other.

CONTENTS

1. Overview and Key Difference
2. What is Sympathetic Nervous System
3. What is Parasympathetic Nervous System
4. Similarities Between Sympathetic and Parasympathetic Nervous System
5. Side by Side Comparison – Sympathetic vs Parasympathetic Nervous System in Tabular Form
6. Summary

What is Sympathetic Nervous System?

Sympathetic nervous system is one of the two parts of the autonomic nervous system. It composed of a nerve network made up of short preganglionic axons that extend to ganglia situated near thoracic and lumbar regions of the spinal cord and of long postganglionic neurons extending from ganglia to target organs. Hence, the fibres of sympathetic efferent neurons also refer as thoracolumbar outflow.

The main function of the sympathetic nervous system is to prepare the body for emergency situations and to produce rapid mobilizations to avoid the danger. In simple words, the sympathetic nervous system controls the body’s “fight or flight” responses during the threat situations.

What is Parasympathetic Nervous System?

Parasympathetic nervous system comprises of preganglionic axons that are organ-associated ganglions in the cranial and sacral regions of the spinal cord, and of short postganglionic neurons extending from ganglia to target organs. Thus, the fibres of parasympathetic efferent neurons also refer to as craniosacral outflow.

Moreover, Acetylcholine is the neurotransmitter at the terminal synapses in this nervous system. This system is responsible for maintaining the activities such as “rest- and – digest” or “feed- and- breed” that occurs when the body is at rest.

What are the Similarities Between Sympathetic and Parasympathetic Nervous System?

• Sympathetic and Parasympathetic Nervous System is parts of the autonomic nervous system.
• Also, bothy belong to the peripheral nervous system.
• And, they are responsible for involuntary responses of the body.

What is the Difference Between Sympathetic and Parasympathetic Nervous System?

Sympathetic and Parasympathetic Nervous System are two main parts of the autonomic nervous system. The difference between sympathetic and parasympathetic nervous system is that the sympathetic nervous system functions to mobilize the body’s fight-or-flight response while parasympathetic nervous system functions to control the homeostasis of the body.

The following infographic indicates more facts regarding the difference between sympathetic and parasympathetic nervous system.

Summary – Sympathetic vs Parasympathetic Nervous System

The autonomic nervous system comprises two main nervous systems that are sympathetic nervous system and parasympathetic nervous system. This system controls the functions of organs as well as controls some muscles. The sympathetic nervous system controls the body when there is a threat. In simple words, it controls the body’s “fight or flight” responses. On the other hand, the parasympathetic nervous system controls the “rest and digest” functions of the body. This is the main difference between sympathetic and parasympathetic nervous system.

Reference:

1.“Sympathetic Nervous System.” ScienceDaily, ScienceDaily. Available here  
2.“Parasympathetic Nervous System.” Wikipedia, Wikimedia Foundation, 4 Sept. 2018. Available here  

Image Courtesy:

1.”1501 Connections of the Sympathetic Nervous System”By OpenStax College – Anatomy & Physiology, Connexions Web site. , Jun 19, 2013., (CC BY 3.0) via Commons Wikimedia  
2.”The Autonomic Nervous System”By Geo-Science-International – Own work, (CC0) via Commons Wikimedia