Autonomic Nervous System

The autonomic nervous system (ANS) is made up of nerves that control the automatic functions throughout the body. It is the master regulator, controlling heart rate, blood pressure, temperature, respiration, sweating, digestion, and other vital functions. These systems operate without you consciously thinking about them because the autonomic nervous system provides the nerve messaging connection between these system organs and the brain. Let’s start thinking about the path these nerves have to take from the heart or digestive system to the brain, where does everything have to pass to get to and from the brain? The neck. Everything goes through the neck.
The autonomic nervous system is made up of two subsystems: the sympathetic autonomic nervous system (SANS) and the parasympathetic autonomic nervous system (PANS). Most organs are directed by both the sympathetic and parasympathetic systems. The sympathetic autonomic nervous system is usually more of a stimulatory system, increasing heart rate and blood pressure when necessary.
Where the parasympathetic autonomic nervous system, generally slows bodily processes, such as reducing heart rate and blood pressure. There are certainly exceptions. Digestion and urination, for instance, are stimulated by the parasympathetic autonomic nervous system and slowed by the sympathetic autonomic nervous system. The sympathetic autonomic nervous system triggers emergency responses or the “fight or flight” responses to prepare for stressful situations and controls the body’s response to stress. The parasympathetic autonomic nervous system conserves energy and restores tissues for ordinary functions, helping to return the body’s equilibrium to the resting state.
(Source: Ross Hauser, MD, Caring Medical Florida)