Autonomic nervous system


The autonomic nervous system

The autonomic nervous system is responsible for all the body reactions independent from our will. We can differentiate between the sympathetic nervous system, with stimulating function and the parasympathetic nervous system, with inhibiting function.

The sympathetic and parasympathetic nervous systems operate on the opposites basis. While the sympathetic nervous system, e.g. accelerates the breath and heartbeat pace, narrows the blood vessels, increases the blood pressure, and slows down the intestinal peristalsis, the parasympathetic nervous system reacts conversely : slowing down the breath and heartbeat pace, decreasing blood pressure and accelerating the intestinal peristalsis.


The sympathetic nervous system is responsible for preparing the organism of a fight or escape. It is active under stress. Once the threat is over, this system switches off and the effects of its stimulation are neutralized by the parasympathetic nervous system. The day releases the sympathetic nervous system operation, while the night prefers the parasympathetic nervous system.

The sympathetic nervous system causes in the body:

pupil dilation


smooth muscle contraction, vasoconstriction of skeletal muscles, resulting in blood pressure increase


faster heart beat


secretion of scarce and dense saliva


effective decomposition of glycogen in the liver


goose pimples


wet and cold hands


bronchial tubes dilating


“fight or run” reaction


urination need, with simultaneous contraction of the bladder sphincter


inhibited intestinal peristalsis


tendency for deficiency in gastric juice


stimulating adrenal glands for adrenaline production


The parasympathetic nervous system is responsible for:

pupil narrowing


decreased contraction strength of the heart muscle


widening of blood vessels, and thus low blood pressure


secretion of high quantity of liquid saliva


increased insulin secretion


occasional or no goose pimples


dry and warm hands


narrowing of bronchial tubes


“rest and digest slowly” reaction


bladder contraction and emptying


intensified contractions of the digestive tract


increased secretion of gastric juice


frequent skin itching


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