Thus, the parasympathetic system can produce specific, localized responses in effector organs, such as the following: Blood vessels of the head, neck, and thoracoabdominal viscera Lacrimal and salivary glands Smooth muscle of glands and viscera (eg, liver, spleen, colon, kidneys, bladder, genitals) Muscles of the pupil Physiology of the Autonomic Nervous System The autonomic nervous system controls blood pressure (BP), heart rate, body temperature, weight, digestion, metabolism, fluid and electrolyte balance, sweating, urination, defecation, sexual response, and other processes.