Is the reaction of "fight of flight" due to the action of the parasympathetic nervous system or the sympathetic?

The autonomic nervous system, a subdivision of the efferent peripheral nervous system, functions automatically without conscious effort. It regulates the functions of internal organs, controls glands, smooth muscle and cardiac muscle.

There are two parts of the autonomic nervous system. The sympathetic division and the parasympathetic division.

The sympathetic division prepares us for physical activity by increasing blood pressure and heartbeat rate. It increases breathing rates, and it stimulates sweating. It also causes the release of glucose from the liver as a quick source of energy. This system is called the "fight or flight system", because it prepares us to face a threat or flee quickly from it.

The Functions of Sympathetic Nervous System :

The parasympathetic division, on the other hand, stimulates digestion, urination and defecation. It also counteracts the effects of the sympathetic division by slowing down heart rate, lowering blood pressure, and slowing the breathing rate. It is also responsible for the constriction of the pupil of the eye. In contrast to the sympathetic system, this division is called the "rest and repose system".