The nervous system that kicked Justin into high gear is the sympathetic nervous system.
The autonomic nervous system can be classified into the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system. The sympathetic division of the autonomic nervous system is involved in stimulating the body for a fight-or-flight response. It is responsible for preparing the body to respond in a threatening situation. It prepares the person by stimulating the adrenal cortex for the secretion of the hormones called the norepinephrine and epinephrine.