Parasympathetic Nerve vs. Sympathetic Nerve

Attribute	Parasympathetic Nerve	Sympathetic Nerve
Origin	Craniosacral	Thoracolumbar
Location of Ganglia	Near or within target organs	Close to spinal cord
Neurotransmitter	Acetylcholine	Acetylcholine (preganglionic) and norepinephrine (postganglionic)
Effects on Heart Rate	Decreases heart rate	Increases heart rate
Effects on Digestion	Increases digestion and peristalsis	Decreases digestion and peristalsis

Introduction

The autonomic nervous system is responsible for regulating involuntary bodily functions such as heart rate, digestion, and respiratory rate. It is divided into two main branches: the parasympathetic nervous system and the sympathetic nervous system. While both systems work together to maintain homeostasis in the body, they have distinct attributes that set them apart.

Anatomy

The parasympathetic nervous system originates from the cranial nerves and the sacral spinal cord. It is often referred to as the "rest and digest" system because it is responsible for conserving energy and promoting digestion. In contrast, the sympathetic nervous system arises from the thoracic and lumbar regions of the spinal cord. It is known as the "fight or flight" system as it prepares the body for action in response to stress or danger.

Neurotransmitters

One of the key differences between the parasympathetic and sympathetic nervous systems lies in the neurotransmitters they use to communicate with target organs. The parasympathetic system primarily releases acetylcholine, which slows down heart rate and promotes digestion. On the other hand, the sympathetic system releases norepinephrine, which increases heart rate and redirects blood flow to muscles during times of stress.

Effects on Organs

Both the parasympathetic and sympathetic nervous systems have specific effects on various organs in the body. For example, the parasympathetic system stimulates salivation, lacrimation, and digestion, while the sympathetic system inhibits these processes. Additionally, the parasympathetic system constricts the pupils and promotes bladder emptying, whereas the sympathetic system dilates the pupils and inhibits bladder emptying.

Response to Stress

When faced with a stressful situation, the sympathetic nervous system is activated to prepare the body for action. This results in an increase in heart rate, dilation of the airways, and release of glucose into the bloodstream. In contrast, the parasympathetic system works to counteract the effects of stress by slowing down heart rate, constricting airways, and promoting relaxation.

Role in the Body

While the sympathetic nervous system is crucial for survival in dangerous situations, the parasympathetic system plays a vital role in maintaining overall health and well-being. The parasympathetic system helps to conserve energy, promote digestion, and regulate bodily functions at rest. In contrast, the sympathetic system is responsible for mobilizing the body's resources to deal with stress and threats.

Balance and Homeostasis

Both the parasympathetic and sympathetic nervous systems work together to maintain a delicate balance in the body known as homeostasis. This balance is essential for optimal functioning of bodily systems and overall health. When one system is overactive or underactive, it can lead to various health problems such as hypertension, digestive issues, or anxiety disorders.

Conclusion

In conclusion, the parasympathetic and sympathetic nervous systems have distinct attributes that allow them to perform different functions in the body. While the sympathetic system prepares the body for action in response to stress, the parasympathetic system works to conserve energy and promote relaxation. Both systems are essential for maintaining homeostasis and overall health, highlighting the importance of a balanced autonomic nervous system.