Answer:
Release of adrenaline by the adrenal glands.
Step-by-step explanation:
Adrenaline hormone also known as epinephrine is an important part of sympathetic nervous system. It is released from adrenal medulla through a sequence of events in a situation of "fight or flight" or we can say in a life threatening situation. This hormone causes our muscles to perform vigorous activities so that body could respond accordingly. Chemically adrenaline hormone is synthesized by using "tyrosine" as a precursor which after a series of enzymatic actions gets converted into L-dopa and then dopamine then nor-adrenaline and finally into adrenaline.