What Is the Autonomic Nervous System?
The autonomic nervous system (ANS) is the portion of the nervous system that controls the function of the different organs and systems of the body. For instance, it regulates body temperature, blood pressure, heartbeat rate, and bowel and bladder tone, among many other variables. It is “autonomic” because our mind does not govern its performance; rather, it works below the level of consciousness. One striking characteristic of this system is the rapidity and intensity of the onset of its action and its dissipation. Centers located in the central nervous system (brain stem, hypothalamus, and thalamus) and in the spinal cord activate the ANS. These centers also receive input from the limbic system and other higher brain areas. This means that the ANS is the interface between mind and body functions. These connections enable the ANS to be the main component of the stress response system in charge of fight-or-flight reactions. The ANS works closely with the endocrine system (the hormonal s
