What is the Difference Between Sympathetic and Parasympathetic Nervous System?

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The sympathetic and parasympathetic nervous systems are two parts of the autonomic nervous system, which controls involuntary functions within the body. They both control the same parts of the body and general functions but have opposing effects.

The sympathetic nervous system (SNS) is responsible for preparing the body for the "fight or flight" response during stressful or dangerous situations. Its effects include increasing heart rate, breathing ability, eyesight, and slowing down processes like digestion. The SNS is activated when the body is stressed, in danger, or physically active.

On the other hand, the parasympathetic nervous system (PSNS) inhibits the body from overworking and restores it to a calm and composed state. It controls the body's response during times of rest and is responsible for functions like digestion, relaxation, and repair. The parasympathetic nervous system is dominant during quiet, resting conditions.

In summary, the major differences between the sympathetic and parasympathetic nervous systems are:

  • Sympathetic nervous system prepares the body for "fight or flight" response, while the parasympathetic nervous system restores the body to a calm state.
  • Sympathetic nervous system increases heart rate, respiration, and blood flow to muscles, while the parasympathetic nervous system decreases them and promotes digestion and relaxation.
  • Sympathetic nervous system is activated during stress, danger, or physical activity, while the parasympathetic nervous system is dominant during rest and relaxation.

Comparative Table: Sympathetic vs Parasympathetic Nervous System

The sympathetic and parasympathetic nervous systems are two main divisions of the autonomic nervous system (ANS), which is responsible for the involuntary functions of the human body. They have different functions and effects on various organ systems. Here is a table summarizing their differences:

Feature Sympathetic Nervous System Parasympathetic Nervous System
Function Controls the body's response during perceived threat, preparing the body for "fight or flight". Controls homeostasis and the body's rest-and-digest response.
Origin Thoracic and lumbar regions of the spinal cord. Sacral region of the spinal cord, medulla, and cranial nerves 3, 7, 9, and 10.
Cardiovascular System (heart rate) Increases heart rate and contraction. Decreases heart rate.
Pulmonary System (lungs) Dilates bronchial tubes. Constricts bronchial tubes.
Musculoskeletal System Contracts muscles. Relaxes muscles.
Pupils Dilates. Constricts.

In summary, the sympathetic nervous system prepares the body for action in response to perceived threats, while the parasympathetic nervous system helps the body recover and maintain homeostasis.