The sympathetic nervous system can increase heart rate ; make bronchial passages wider ; decrease motility ( movement ) of the large intestine ; make blood vessels narrower ; increase peristalsis in the esophagus ; cause pupil dilation , piloerection ( goose bumps ) and perspiration ( sweating ) ; and raise blood pressure . For example , the sympathetic nervous system can accelerate heart rate ; widen bronchial passages ; decrease motility ( movement ) of the large intestine ; constrict blood vessels ; increase peristalsis in the esophagus ; cause pupillary dilation , piloerection ( goose bumps ) and perspiration ( sweating ) ; and raise blood pressure .