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Parasympathetic Nervous
System The Parasympathetic system is the branch of the Autonomic Nervous System (ANS) responsible for the body’s ability to recuperate and return to a balanced state (known as "homeostasis") after experiencing pain or stress. While the Sympathetic system is also known as the "fight or flight" response, the Parasympathetic is often called "relax and renew." The Parasympathetic functions in opposition to the Sympathetic nervous system. When the sympathetic system activates in response to some sort of stressor, the parasympathetic reacts in turn to bring the body back to a state of equilibrium. The Parasympathetic system is consistently active at a low level, but levels of activity increase when it is necessary to bring the body back to a balanced state from a state of elevated Sympathetic activity. |
| The primary Parasympathetic nerve is the vagus nerve, also known as cranial nerve X. When active, the Parasympathetic system slows down heart rate, dilates blood vessels, activates digestion, and stores energy. Unlike the Sympathetic system, the Parasympathetic response does not necessarily perform all of these functions at once, but selectively, as needed. | |
Autonomic Nervous System
The autonomic nervous system (ANS) is the part of the body’s
peripheral nervous system responsible for maintaining homeostasis,
or balance. As opposed to the sensory nervous system, which
regulates part of the body which we can control voluntarily (e.g.
muscles), the ANS regulates functions which are mainly
involuntary. Involuntary functions include heart rate, digestion,
dilation and constriction of blood vessels, and hormone secretion,
among others.
The ANS is primarily composed of two branches: the Parasympathetic
Nervous System and the Sympathetic Nervous System. The
Sympathetic and Parasympathetic branches constantly work in
opposition to one another to achieve and maintain a balanced
physiological state.
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Sympathetic Nervous
System The Sympathetic nervous system is better known as the “flight or flight” response. It is the branch of the Autonomic Nervous System (ANS) that controls the body’s reaction to physical and emotional stressors. The Sympathetic system is constantly active, but activity increases in response to stressful stimuli and decreases in response to Parasympathetic activation. When the Sympathetic is activated, adrenaline is released, heart rate increases, blood vessels constrict, sweating occurs, digestion is inhibited, and the pupils dilate. This response is useful in the short term because it aides the body in responding quickly and effectively to stress. In the long term, the Sympathetic response can become harmful. This is because the functions of Sympathetic activation put additional stress on the nervous system. If the Sympathetic system remains highly active, the Parasympathetic response will not activate and return the body to homeostasis. |
| This means the body does not get the chance to recover from stress. Chronic Sympathetic activation can cause Allostatic Load. | |
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Allostatic Load Allostasis refers to the active process by which the body responds to daily events and maintains homeostasis (allostasis literally means “achieving stability through change”). The stress response, which is controlled by the sympathetic nervous system, plays a necessary and important role in adaptation to environments. Allostatic load refers to the wear and tear on the body that results from either too much stress or inefficient management of stress. |
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This could mean the body
is: 1 - Not turning off the stress response when it is no longer needed, 2 - Not turning on an adequate response to stress in the first place, or, 3 - Getting used to the recurrence of the same stressor over and over again. Chronic stressors or an inability to restore homeostasis after a stressor take a dramatic toll on the body’s ability to recuperate and renew. The job of the parasympathetic nervous system is impaired. Over time, if it is not counteracted with the relaxation response, the body’s response can cause cumulative strain on multiple organs and tissues, causing illness and disease. The use of biofeedback training can help restore the body to a balanced state of functioning. When the body is unbalanced illness and disease may erupt with devastating effects.
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