If you are startled by the sound of a loud explosion, the nervous system will become dominant.

If you are startled by the sound of a loud explosion, the sympathetic nervous system will become dominant. The sympathetic nervous system is responsible for regulating not only the functioning of the visceral organs (kidneys, digestive system and circulatory system) but also all the automatic functions of the organism, such as breathing, circulation, digestion and elimination. 

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