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Parasympathetic Nervous System (PNS)
A division of the autonomic nervous system. The PNS causes slowing down of the heartbeat, lowering of blood pressure, constriction of the pupils, increased blood flow to and from the skin, and peristalsis of the gastrointestinal (GI) tract. The PNS's major function is to return the body functions to normal after they have been alerted by sympathetic simulation. The PNS works in complement with the sympathetic nervous system. When the body senses danger, the sympathetic system prepares it to deal with this danger, and the PNS reverses this system when the danger has passed. The PNS is a portion of the visceral branch of the peripheral nervous system. The main nerves of the PNS are the 10th cranial nerves, also known as the vagus ...