What is "parasympathetic nervous system"?

The parasympathetic nervous system, a division of the autonomic nervous system, is responsible for regulating and maintaining the body's essential functions during rest and relaxation. It acts in opposition to the sympathetic nervous system, which triggers the body's fight-or-flight response. The parasympathetic nervous system helps promote rest, digestion, and conservation of energy by slowing heart rate, increasing digestion and glandular activity, and promoting relaxation. It is involved in processes such as stimulating digestion, contracting the pupils, and promoting salivation. Through its intricate network of nerves and neurotransmitters, the parasympathetic nervous system plays a vital role in maintaining homeostasis and allowing the body to rest and recover.