Answer:
sympathetic nervous system
Step-by-step explanation:
The sympathetic nervous system is the part of the autonomic nervous system that is activated when the body is faced with acute stress or when the body perceives a threat. When the body perceives a threat or is faced with stress, the sympathetic nervous is called into action by initiating series of responses that are referred to as "fight or flight" responses. These responses involves physiological changes that are initiated to put the body in full alert to enable it deal with the stressor or threat as hormone such as norepinephrine is released into the blood stream.
"Fight or flight" responses include increased heart rate, increased perspiration, increased blood sugar level, increased blood pressure, dilation of pupil etc.