The parasympathetic (PNS) is responsible for body maintenance and building new tissue, healing, controlling inflammation, and your immune system. This is your fun and relax system.  Keep the heart rate slow, reduce how fast you take breaths.  Digest all that food you ate.  The vagus nerve leaves your brain and travels throughout the body following the carotid artery and then the aorta.  It helps regulate most of digestive organs including the gallbladder.  It also controls the pacemaker of the heart or the sinoatrial node.  It even helps to decrease blood glucose by getting it turned into glycogen and stored in your liver.